Add regression tests for ilc --help instruction set help text - #125735

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Add regression tests for ilc --help instruction set help text#125735
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Description

ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.

Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:

  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt

This section details on the original issue you should resolve

<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>
<issue_description>### Description

Hello,

Description

When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.

1. Massive duplicates in the per-architecture lists

Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...
(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)

The same problem exists in the x86 section.

This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.

2. Predefined CPU groups that are no longer supported are still listed

The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:
x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...

According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .

Users who copy-paste from --help will get compile "Unrecognized instruction set" errors

Image

Reproduction Steps

  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section

Expected behavior

  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.

Actual behavior

Noisy output with dozens of repeated values + outdated predefined groups.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

Thank you for improving the developer experience of NativeAOT!</issue_description>

Comments on the Issue (you are @copilot in this section)

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CopilotAIand others added 2 commits March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI changed the title [WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI requested a review from jtschusterMarch 18, 2026 17:29
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jtschuster commented Mar 18, 2026

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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026
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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
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}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Add regression tests for ilc --help instruction set help text - #125735
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Add regression tests for ilc --help instruction set help text#125735
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copilot/fix-ilc-help-output-duplicates
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
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CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI
requested a review
from jtschusterMarch 18, 2026 17:29
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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Add regression tests for ilc --help instruction set help text - #125735
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Add regression tests for ilc --help instruction set help text#125735
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CopilotAI
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
📍 Connect Copilot coding agent with Jira, Azure Boards or Linear to delegate work to Copilot in one click without leaving your project management tool.
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Tagging subscribers to this area: @dotnet/runtime-infrastructure

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CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI
requested a review
from jtschusterMarch 18, 2026 17:29
@jtschuster
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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


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@jtschuster

, '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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Add regression tests for ilc --help instruction set help text - #125735
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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
📍 Connect Copilot coding agent with Jira, Azure Boards or Linear to delegate work to Copilot in one click without leaving your project management tool.
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Mar 18, 2026

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Tagging subscribers to this area: @dotnet/runtime-infrastructure

See info in area-owners.md if you want to be subscribed.
CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI
requested a review
from jtschusterMarch 18, 2026 17:29
@jtschuster
jtschuster
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Mar 18, 2026

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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


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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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Add regression tests for ilc --help instruction set help text - #125735
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Add regression tests for ilc --help instruction set help text#125735
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
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added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


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@jtschuster

, '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('^' + ".*" + '

Skip to content
Add regression tests for ilc --help instruction set help text - #125735
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jtschuster with Copilot wants to merge 3 commits into
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copilot/fix-ilc-help-output-duplicates
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Add regression tests for ilc --help instruction set help text#125735
jtschuster with Copilot wants to merge 3 commits into
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
📍 Connect Copilot coding agent with Jira, Azure Boards or Linear to delegate work to Copilot in one click without leaving your project management tool.
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Tagging subscribers to this area: @dotnet/runtime-infrastructure

See info in area-owners.md if you want to be subscribed.
CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI
requested a review
from jtschusterMarch 18, 2026 17:29
@jtschuster
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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

Open


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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


2 participants

@jtschuster

, '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('^' + ".*" + '

Skip to content
Add regression tests for ilc --help instruction set help text - #125735
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jtschuster with Copilot wants to merge 3 commits into
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copilot/fix-ilc-help-output-duplicates
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Add regression tests for ilc --help instruction set help text#125735
jtschuster with Copilot wants to merge 3 commits into
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copilot/fix-ilc-help-output-duplicates
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CopilotAI
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
Comments on the Issue (you are @copilot in this section)
📍 Connect Copilot coding agent with Jira, Azure Boards or Linear to delegate work to Copilot in one click without leaving your project management tool.
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Mar 18, 2026

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Tagging subscribers to this area: @dotnet/runtime-infrastructure

See info in area-owners.md if you want to be subscribed.
CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
CopilotAI
changed the title
[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
CopilotAI
requested a review
from jtschusterMarch 18, 2026 17:29
@jtschuster
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Mar 18, 2026

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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

Open


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@jkotas
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May 22, 2026 17:03
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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


2 participants

@jtschuster

, '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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Add regression tests for ilc --help instruction set help text - #125735
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jtschuster with Copilot wants to merge 3 commits into
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copilot/fix-ilc-help-output-duplicates
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Add regression tests for ilc --help instruction set help text#125735
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Mar 18, 2026•

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Description
ilc --help output for --instruction-set had two issues: massive duplicates in per-architecture instruction set lists (e.g., base, base, base, avx2, avx2, avx2, ...) and listing the removed x86-64 predefined CPU group that produces "Unrecognized instruction set" errors when used.
Both issues are already fixed in main — duplicates by DistinctBy (PR #119368), and x86-64 removal from InstructionSetDesc.txt. This PR adds regression tests to prevent recurrence:
  • HelpTextShowsNoDuplicateInstructionSetNames — simulates the exact DistinctBy + Specifiable logic from PrintExtendedHelp and asserts uniqueness per architecture
  • AllSpecifiableNamesAppearInHelpText — verifies DistinctBy ordering doesn't shadow specifiable names behind non-specifiable entries with the same key
  • AllCpuGroupNamesResolveToValidInstructionSets — exercises InstructionSetSupportBuilder.AddSupportedInstructionSet for every predefined CPU group to catch stale/broken group definitions
  • AllCpuGroupNamesAreUnique / NoPredefinedGroupNamedX86Dash64WithoutVersion — guards against re-introducing removed or duplicate group names
Original prompt
This section details on the original issue you should resolve
<issue_title>ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups</issue_title>

<issue_description>### Description
Hello,
Description
When running ilc --help (from package runtime.win-x64.Microsoft.DotNet.ILCompiler10.0.5, the latest stable at the moment), the output for the --instruction-set option is malformed.
1. Massive duplicates in the per-architecture lists
Current output (x64 section excerpt):
x64: base, base, base, sse4.2, sse4.2, sse4.2, sse4.2, sse4.2, avx, avx2, avx2, avx2, avx2, avx2, avx2, avx2, avx512, avx512, ...

(and many more repeated values for avx2, avx512*, aes, gfni, avxvnniint, etc.)
The same problem exists in the x86 section.
This looks like the help text is generated by concatenating several internal arrays/lists without proper deduplication or formatting.
2. Predefined CPU groups that are no longer supported are still listed
The help still mentions:
The following CPU names are predefined groups of instruction sets and can be used in --instruction-set too:

x86-64, x86-64-v2, x86-64-v3, x86-64-v4, armv8-a, armv8.1-a, ...
According to recent changes in .NET 10 / NativeAOT, the old x86-64* / x86-64-v* aliases have been removed or renamed .
Users who copy-paste from --help will get compile "Unrecognized instruction set" errors
Image
Reproduction Steps
  1. Download runtime.win-x64.Microsoft.DotNet.ILCompiler 10.0.5
  2. Run: ilc --help
  3. Scroll to the --instruction-set section
Expected behavior
  • Clean, deduplicated list of supported instruction sets per architecture.
  • Only currently supported predefined CPU groups should be listed.
  • The help text should be readable and accurate.
Actual behavior
Noisy output with dozens of repeated values + outdated predefined groups.
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
Thank you for improving the developer experience of NativeAOT!</issue_description>
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Mar 18, 2026

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CopilotAIand others
added 2 commits
March 18, 2026 17:21
@jtschuster
Add regression tests for instruction set help text (no duplicates, va…
e750d93
…lid CPU groups)
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
@jtschuster
Address code review: strengthen SetEquals assertion, use case-insensi…
8bdb1ee
…tive comparison
Co-authored-by: jtschuster <36744439+jtschuster@users.noreply.github.com>
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[WIP] Fix duplicate entries in ilc --help instruction set outputAdd regression tests for ilc --help instruction set help textMar 18, 2026
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from jtschusterMarch 18, 2026 17:29
@jtschuster
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Mar 18, 2026

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Not sure this warrants additional tests if it's already fixed main.

This was referenced Mar 18, 2026

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ilc --help for --instruction-set contains many duplicates and lists removed/outdated predefined CPU groups


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