Enable ICF on Linux - #129762

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jkotas merged 7 commits into
dotnet:mainfrom
MichalPetryka:patch-64
Jul 3, 2026
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Enable ICF on Linux#129762
jkotas merged 7 commits into
dotnet:mainfrom
MichalPetryka:patch-64

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@MichalPetryka

@MichalPetrykaMichalPetryka commented Jun 23, 2026•
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CI is green and it saves on average 2% in size.

@MichalPetryka
Try enabling ICF on Linux
80202e3
Opening to see CI results and size diffs
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MichalPetryka commented Jun 24, 2026

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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.

Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.

Also, it seems like NativeAOT doesn't use the flags from here.

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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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am11 commented Jun 24, 2026

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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.

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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.

My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.

@am11am11 added area-Infrastructure-coreclr Only use for closed issues and removed area-NativeAOT-coreclr labels Jun 24, 2026
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Do you see any size difference before/after on linux?

$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;

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Do you see any size difference before/after on linux?

$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;

I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.

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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
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1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
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27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
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17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
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28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
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4836465648437168+72512+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so.dbg
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
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714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL

@MichalPetryka

MichalPetryka commented Jun 24, 2026

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@am11 Can you show the total without .dbg files?

Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?

am11
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Comment threadeng/native/configurecompiler.cmake Outdated
@MichalPetryka@am11
Update eng/native/configurecompiler.cmake
c33eafe
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?

| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |

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MichalPetryka marked this pull request as ready for review June 24, 2026 09:22
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captured befroe.md and after.md with this:

echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}

then asked AI to compute deltas (which used python script).

@MichalPetrykaMichalPetryka changed the title Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026
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/azp run runtime-coreclr outerloop, runtime-extra-platforms

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Failures all unrelated, either non Linux or networking errors.

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@jkotas Do you know who'd be the right person to review this?

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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object
(including a pointer to an object and a subobject at its beginning) or function, ...".

We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.

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Thanks!

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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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Enable ICF on Linux - #129762
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Enable ICF on Linux#129762
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CI is green and it saves on average 2% in size.
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Try enabling ICF on Linux
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so.dbg
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so.dbg
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so
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16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so.dbg
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
4659357646598952+5376+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so.dbg
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
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28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x64_arm64.so
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20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
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6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
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714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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Enable ICF on Linux (#129762)
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It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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, 'i');
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})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Enable ICF on Linux - #129762
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CI is green and it saves on average 2% in size.
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Try enabling ICF on Linux
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Opening to see CI results and size diffs
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so.dbg
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so.dbg
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so.dbg
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so.dbg
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
4659357646598952+5376+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so.dbg
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so
4836465648437168+72512+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so.dbg
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so
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714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
c33eafe
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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, 'i');
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}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Enable ICF on Linux - #129762
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jkotas merged 7 commits into
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MichalPetryka:patch-64
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Enable ICF on Linux#129762
jkotas merged 7 commits into
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Jun 23, 2026•

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CI is green and it saves on average 2% in size.
@MichalPetryka
Try enabling ICF on Linux
80202e3
Opening to see CI results and size diffs
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@MichalPetryka
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so.dbg
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so.dbg
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so.dbg
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so.dbg
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
4659357646598952+5376+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so.dbg
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so
4836465648437168+72512+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so.dbg
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so
1595335215953352+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/R2RDump/libcoredistools.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
c33eafe
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Enable ICF on Linux - #129762
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Enable ICF on Linux#129762
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CI is green and it saves on average 2% in size.
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Try enabling ICF on Linux
80202e3
Opening to see CI results and size diffs
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Comment threadeng/native/configurecompiler.cmake
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Update eng/native/configurecompiler.cmake
d6cf672
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
@MichalPetryka
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so.dbg
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so.dbg
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so.dbg
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so.dbg
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
4659357646598952+5376+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so.dbg
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so
4836465648437168+72512+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so.dbg
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so
1595335215953352+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/R2RDump/libcoredistools.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Enable ICF on Linux - #129762
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CI is green and it saves on average 2% in size.
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Try enabling ICF on Linux
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Opening to see CI results and size diffs
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
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27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
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17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
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41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
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6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
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4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
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39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
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28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
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27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
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28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Enable ICF on Linux - #129762
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jkotas merged 7 commits into
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MichalPetryka:patch-64
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Enable ICF on Linux#129762
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CI is green and it saves on average 2% in size.
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Try enabling ICF on Linux
80202e3
Opening to see CI results and size diffs
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Update eng/native/configurecompiler.cmake
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Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
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28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
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4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
@MichalPetryka
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
c33eafe
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Jun 26, 2026

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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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@MichalPetryka@am11
@jkotas@eiriktsarpalis
Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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@jkotasjkotasjkotas approved these changes
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@MichalPetryka@am11@AndyAyersMS@jkotas@teo-tsirpanis

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Enable ICF on Linux - #129762
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jkotas merged 7 commits into
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MichalPetryka:patch-64
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Enable ICF on Linux#129762
jkotas merged 7 commits into
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@MichalPetryka
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Jun 23, 2026•

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CI is green and it saves on average 2% in size.
@MichalPetryka
Try enabling ICF on Linux
80202e3
Opening to see CI results and size diffs
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@am11 Since I think you worked in this area the most, what do you think about this? It seems that the GCC build job failed cause ld does not support the flag.
Do the official builds use lld instead? If not, it probably doesn't make sense to do any checking for linker here.
Also, it seems like NativeAOT doesn't use the flags from here.
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Comment threadeng/native/configurecompiler.cmake
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Update eng/native/configurecompiler.cmake
d6cf672
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
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@MichalStrehovsky, experimented with it earlier. We may need changes from #87045.
My intent here was to only enable it for native code in the runtime, I'd leave the handling of NAOT outputs to @MichalStrehovsky.
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
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Do you see any size difference before/after on linux?
$ ./build.sh clr+libs -c Release
$ find artifacts/bin/coreclr/linux.x64.Release -name '*.so*' -exec du -sh {} \;
I currently do not have a Linux machine on hand to test it, that's why I wanted to see how it impacts rt-sz.
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Before (bytes)After (bytes)Diff (bytes)Diff %Path
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordaccore.so.dbg
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so.dbg
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrjit.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so.dbg
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libclrgc.so
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclr.so.dbg
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/sharedFramework/libcoreclrtraceptprovider.so.dbg
14257201295560-130160-9.13%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so
4659357646598952+5376+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so.dbg
17657121723664-42048-2.38%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so
42528644284640+31776+0.75%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so.dbg
41905364189608-928-0.02%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2-published/libclrjit_universal_wasm_arm64.so
35424483529920-12528-0.35%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so
4836465648437168+72512+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm64_arm64.so.dbg
6414818464237208+89024+0.14%artifacts/bin/coreclr/linux.arm64.Release/libmscordaccore.so.dbg
319464318312-1152-0.36%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so
648744540616-108128-16.67%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so
40859284140104+54176+1.33%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so.dbg
4672465646794416+69760+0.15%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so.dbg
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so
756904745544-11360-1.50%artifacts/bin/coreclr/linux.arm64.Release/libclrgcexp.so
1950434419491816-12528-0.06%artifacts/bin/coreclr/linux.arm64.Release/libclrjit.so.dbg
39717443970592-1152-0.03%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-simple.so.dbg
1366076013661672+912+0.01%artifacts/bin/coreclr/linux.arm64.Release/libmscordbi.so.dbg
58196565801704-17952-0.31%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so.dbg
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_unix_x64_arm64.so
3833342438348496+15072+0.04%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_arm_arm64.so.dbg
4654174446547728+5984+0.01%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_win_x86_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/crossgen2/libclrjit_universal_wasm_arm64.so
352648351720-928-0.26%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-counter.so
53078965216440-91456-1.72%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so
1595335215953352+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/R2RDump/libcoredistools.so
714296696344-17952-2.51%artifacts/bin/coreclr/linux.arm64.Release/libclrgc.so
382832349072-33760-8.82%artifacts/bin/coreclr/linux.arm64.Release/libsuperpmi-shim-collector.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so
278832278752-80-0.03%artifacts/bin/coreclr/linux.arm64.Release/libjitinterface_arm64.so.dbg
125775536125815144+39608+0.03%artifacts/bin/coreclr/linux.arm64.Release/libcoreclr.so.dbg
316056316056+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++abi.so.1
14692801469280+0+0.00%artifacts/bin/coreclr/linux.arm64.Release/SuperFileCheck/runtimes/linux-arm64/native/libc++.so.1
16367281594136-42592-2.60%artifacts/bin/coreclr/linux.arm64.Release/libcoreclrtraceptprovider.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/crossgen2/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/arm64/ilc/libclrjit_universal_wasm_arm64.so
3887396838950512+76544+0.20%artifacts/bin/coreclr/linux.arm64.Release/libclrjit_universal_wasm_arm64.so.dbg
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc-published/libclrjit_universal_wasm_arm64.so
28048242746264-58560-2.09%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm64_arm64.so
27625762703024-59552-2.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x86_arm64.so
21170882066624-50464-2.38%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_arm_arm64.so
4939249312-80-0.16%artifacts/bin/coreclr/linux.arm64.Release/ilc/libjitinterface_arm64.so
28492242789064-60160-2.11%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_win_x64_arm64.so
28707842809472-61312-2.14%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_unix_x64_arm64.so
20276881973160-54528-2.69%artifacts/bin/coreclr/linux.arm64.Release/ilc/libclrjit_universal_wasm_arm64.so
106664103208-3456-3.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so
36258163622568-3248-0.09%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so.dbg
4208842088+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so.dbg
1406414064+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Ports.Native.so
574672573520-1152-0.20%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so.dbg
13692161365968-3248-0.24%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.IO.Compression.Native.so
238032238032+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so.dbg
395408391952-3456-0.87%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Native.so.dbg
237544236392-1152-0.48%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Security.Cryptography.Native.OpenSsl.so
6483264832+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Globalization.Native.so
4234442344+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so.dbg
1528015280+0+0.00%artifacts/bin/native/net11.0-linux-Release-arm64/libSystem.Net.Security.Native.so
909602336906807088-2795248-0.31%TOTAL
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@am11 Can you show the total without .dbg files?
Also, it seems like emscripten doesn't support icf even with lld, what's the proper condition for excluding that?
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Update eng/native/configurecompiler.cmake
c33eafe
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
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@am11 Can you show the total without .dbg files?
| 157295704 | 154012152 | -3283552 | -2.09% | TOTAL |
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captured befroe.md and after.md with this:
echo "| Size (human) | Size (bytes) | Path |"; find artifacts/bin/coreclr/linux.arm64.Release artifacts/bin/native/net11.0-linux-Release-arm64 -name '*.so*' | xargs -I{} bash -c 'echo "| $(du -sh "$0" | cut -f1) | $(du -sb "$0" | cut -f1) | $0 |"' {}
then asked AI to compute deltas (which used python script).
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Try enabling ICF on LinuxEnable ICF on LinuxJun 24, 2026

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/azp run runtime-coreclr outerloop, runtime-extra-platforms
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Failures all unrelated, either non Linux or networking errors.
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@jkotas Do you know who'd be the right person to review this?
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This change is not risk-free. --icf=all violates the C/C++ spec guarantees about pointer equality. E.g. from the C23 spec: "Two pointers compare equal if and only if both are null pointers, both are pointers to the same object

(including a pointer to an object and a subobject at its beginning) or function, ...".
We have the equivalent option enabled on Windows, and copilot is not able to find any dependencies on the pointer equality behavior in non-Windows code, so the risk should be acceptable.
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Thanks!
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@MichalPetryka@am11
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Enable ICF on Linux (#129762)
2a91ff6
It saves on average 2% in size.
---------
Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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