JIT: Accelerate floating->long casts on x86 - #125180

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saucecontrol:lng2flt6
Apr 29, 2026
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JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
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saucecontrol:lng2flt6

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@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
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@dotnet/jit-contrib this is ready for review

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Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

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tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
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JIT: Accelerate floating->long casts on x86 - #125180

Merged
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrol

@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
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@dotnet/jit-contrib this is ready for review

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
@tannergooding
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@tannergooding
tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
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JIT: Accelerate floating->long casts on x86 - #125180

Merged
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrol

@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
CopilotAI review requested due to automatic review settings March 4, 2026 19:31
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@dotnet/jit-contrib this is ready for review

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

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src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
@tannergoodingtannergooding added the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 21, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 00:47
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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

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tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
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@tannergooding
tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms"); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
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JIT: Accelerate floating->long casts on x86 - #125180

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tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrol

@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
CopilotAI review requested due to automatic review settings March 4, 2026 19:31
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@dotnet/jit-contrib this is ready for review

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
@tannergoodingtannergooding added the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 21, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 00:47
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Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated

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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

@tannergooding
tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
@tannergooding
tannergooding enabled auto-merge (squash) April 29, 2026 05:30
@tannergooding
tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
135 of 137 checks passed
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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" + '
Skip to content

JIT: Accelerate floating->long casts on x86 - #125180

Merged
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrol

@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
CopilotAI review requested due to automatic review settings March 4, 2026 19:31
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saucecontrol commented Mar 4, 2026

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@dotnet/jit-contrib this is ready for review

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

CopilotAI review requested due to automatic review settings April 16, 2026 19:48

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
@tannergoodingtannergooding added the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 21, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 00:47
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Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated

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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

@tannergooding
tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
@tannergooding
tannergooding enabled auto-merge (squash) April 29, 2026 05:30
@tannergooding
tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
135 of 137 checks passed
@saucecontrol
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JIT: Accelerate floating->long casts on x86 - #125180

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dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
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@dotnet/jit-contrib this is ready for review

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

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src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

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tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
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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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JIT: Accelerate floating->long casts on x86 - #125180

Merged
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6
Apr 29, 2026
Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
CopilotAI review requested due to automatic review settings March 4, 2026 19:31
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saucecontrol commented Mar 4, 2026

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@dotnet/jit-contrib this is ready for review

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
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@EgorBo, please review this community PR.

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
CopilotAI review requested due to automatic review settings April 20, 2026 04:36

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
@tannergoodingtannergooding added the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 21, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 00:47
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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

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tannergooding requested a review from kgApril 22, 2026 17:30
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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
@tannergooding
tannergooding enabled auto-merge (squash) April 29, 2026 05:30
@tannergooding
tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
135 of 137 checks passed
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, '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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JIT: Accelerate floating->long casts on x86 - #125180

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dotnet:mainfrom
saucecontrol:lng2flt6
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Merged

JIT: Accelerate floating->long casts on x86#125180
tannergooding merged 11 commits into
dotnet:mainfrom
saucecontrol:lng2flt6

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@saucecontrolsaucecontrol commented Mar 4, 2026

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This adds floating->long/ulong cast codegen for AVX-512 and AVX10.2 on x86. With this, all non-overflow casts are now hardware accelerated. This is the last bit pulled from #116805.

Typical Diff (double->long AVX-512):

- sub esp, 8- vzeroupper - vmovsd xmm0, qword ptr [esp+0x0C]- sub esp, 8- ; npt arg push 0- ; npt arg push 1- vmovsd qword ptr [esp], xmm0- call CORINFO_HELP_DBL2LNG- ; gcr arg pop 2+ vmovsd xmm0, qword ptr [esp+0x04]+ vcmpordsd k1, xmm0, xmm0+ vcmpge_oqsd k2, xmm0, qword ptr [@RWD00]+ vcvttpd2qq xmm0 {k1}{z}, xmm0+ vpblendmq xmm0 {k2}, xmm0, qword ptr [@RWD08] {1to2}+ vmovd eax, xmm0+ vpextrd edx, xmm0, 1- add esp, 8
ret 8
+RWD00 dq	43E0000000000000h+RWD08 dq	7FFFFFFFFFFFFFFFh-; Total bytes of code 31+; Total bytes of code 53

Full Diffs

Breakdown of the double->long asm:

; load the scalar doublevmovsd xmm0, qword ptr [esp+0x04]; set the low bit of k1 if the scalar value is not NaNvcmpordsd k1,xmm0,xmm0; set the low bit of k2 if the input was greater than or equal to 2^63 (nearest double greater than long.MaxValue)vcmpge_oqsd k2,xmm0, qword ptr [@RWD00]; convert, using k1 mask bit. if the mask bit is not set (meaning we have a NaN), set the value to zerovcvttpd2qqxmm0 {k1}{z},xmm0; if the low bit of k2 is set (meaning overflow), set the value to long.MaxValue, otherwise take the conversion resultvpblendmqxmm0 {k2},xmm0, qword ptr [@RWD08] {1to2}; extract the two 32-bit halves of the long resultvmovd eax,xmm0vpextrd edx,xmm0,1

CopilotAI review requested due to automatic review settings March 4, 2026 15:43
@dotnet-policy-servicedotnet-policy-serviceBot added the community-contribution Indicates that the PR has been added by a community member label Mar 4, 2026
@github-actionsgithub-actionsBot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Mar 4, 2026

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Pull request overview

This PR extends x86 JIT codegen to hardware-accelerate non-overflow floating→long/ulong casts using AVX-512 and AVX10.2, completing the remaining cast-acceleration work pulled from #116805.

Changes:

  • Teach cast helper selection to allow floating↔long casts to stay intrinsic-based on x86 when AVX-512 is available.
  • Add/extend x86 long decomposition logic to generate AVX-512/AVX10.2 sequences for floating→long/ulong and long→floating casts.
  • Introduce a new AVX-512 scalar compare-mask intrinsic and wire it up for immediate bounds + containment.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file
FileDescription
src/coreclr/jit/lowerxarch.cppRefactors vector constant construction and adds containment support for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsicxarch.cppAdds immediate upper-bound handling for the new AVX-512 scalar compare-mask intrinsic.
src/coreclr/jit/hwintrinsiclistxarch.hIntroduces AVX512.CompareScalarMask as a new intrinsic mapping to vcmpss/vcmpsd with IMM.
src/coreclr/jit/flowgraph.cppUpdates helper-requirement logic so x86 floating↔long casts can avoid helper calls when AVX-512 is available.
src/coreclr/jit/decomposelongs.cppImplements the AVX-512/AVX10.2-based lowering/decomposition sequences for floating↔long/ulong on x86.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
CopilotAI review requested due to automatic review settings March 4, 2026 16:08

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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@saucecontrol
saucecontrol marked this pull request as ready for review March 4, 2026 19:31
CopilotAI review requested due to automatic review settings March 4, 2026 19:31
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saucecontrol commented Mar 4, 2026

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@dotnet/jit-contrib this is ready for review

diffs

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp
@JulieLeeMSFT

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@EgorBo, please review this community PR.

CopilotAI review requested due to automatic review settings April 16, 2026 19:48

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/flowgraph.cpp:1347

  • fgCastRequiresHelper on x86 currently only exempts long<->floating casts when InstructionSet_AVX512 is enabled. This PR adds long/floating cast acceleration that can use AVX10.2 (InstructionSet_AVX10v2) as well (e.g., DecomposeLongs::DecomposeCast checks compOpportunisticallyDependsOn(InstructionSet_AVX10v2)). If AVX10v2 is enabled while AVX512 is disabled/unavailable, morphing may still force a helper call and bypass the new codegen. Consider updating the x86 condition to treat AVX10v2 as sufficient (e.g., require helper only when neither AVX512 nor AVX10v2 is available).
#if defined(TARGET_X86) || defined(TARGET_ARM)
if ((varTypeIsLong(fromType) && varTypeIsFloating(toType)) ||
(varTypeIsFloating(fromType) && varTypeIsLong(toType)))
{
#if defined(TARGET_X86)
return !compOpportunisticallyDependsOn(InstructionSet_AVX512);
#else

Comment threadsrc/coreclr/jit/hwintrinsiclistxarch.h Outdated
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 16, 2026 19:55
CopilotAI review requested due to automatic review settings April 20, 2026 04:36

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Comment threadsrc/coreclr/jit/gentree.cpp
Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated
@tannergoodingtannergooding added the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 21, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 00:47
@dotnet-policy-servicedotnet-policy-serviceBot removed the needs-author-action An issue or pull request that requires more info or actions from the author. label Apr 22, 2026

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

Comment threadsrc/coreclr/jit/decomposelongs.cpp Outdated

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CC. @dotnet/jit-contrib, @EgorBo, @kg for secondary review on the community PR

@tannergooding
tannergooding requested a review from kgApril 22, 2026 17:30
@saucecontrol

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Pushed a change to simplify the IR. No change to the codegen.

kg
kg approved these changes Apr 29, 2026
@tannergooding
tannergooding enabled auto-merge (squash) April 29, 2026 05:30
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tannergooding merged commit d1163e5 into dotnet:mainApr 29, 2026
135 of 137 checks passed
@saucecontrol
saucecontrol deleted the lng2flt6 branch April 29, 2026 16:51
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@saucecontrol@JulieLeeMSFT@kg@tannergooding