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Tracking Issue for x87_target_feature #150261

Open
Open
Tracking Issue for x87_target_feature#150261
Labels
A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

Description

@RalfJung
RalfJung
opened on Dec 22, 2025

This is a tracking issue for x87_target_feature, the x87 target feature on x86.

See #44839 for discussion from before this feature got its own tracking issue.

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
Discussion comments will get marked as off-topic or deleted.
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.

Steps

Unresolved Questions

none at the moment

Implementation history

Metadata

Metadata

Assignees

No one assigned

    Labels

    A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions

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Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
      Skip to content
      Tracking Issue for x87_target_feature #150261
      Open
      Open
      Tracking Issue for x87_target_feature#150261
      Labels
      A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
      Description
      @RalfJung
      RalfJung
      opened on Dec 22, 2025
      This is a tracking issue for x87_target_feature, the x87 target feature on x86.
      See #44839 for discussion from before this feature got its own tracking issue.
      About tracking issues
      Tracking issues are used to record the overall progress of implementation.
      
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
      
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
      
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
      
Discussion comments will get marked as off-topic or deleted.
      
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
      Steps
      Unresolved Questions
      none at the moment
      Implementation history
      Metadata
      Metadata
      Assignees
      No one assigned
        Labels
        A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
        Type
        No type
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
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(function(){
try {
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var __re = new RegExp('^' + ".*" + '
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
          Skip to content
          Tracking Issue for x87_target_feature #150261
          Open
          Open
          Tracking Issue for x87_target_feature#150261
          Labels
          A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
          Description
          @RalfJung
          RalfJung
          opened on Dec 22, 2025
          This is a tracking issue for x87_target_feature, the x87 target feature on x86.
          See #44839 for discussion from before this feature got its own tracking issue.
          About tracking issues
          Tracking issues are used to record the overall progress of implementation.
          
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
          
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
          
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
          
Discussion comments will get marked as off-topic or deleted.
          
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
          Steps
          Unresolved Questions
          none at the moment
          Implementation history
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
            Type
            No type
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
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var ref = document.referrer;
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Array.from(node.childNodes).forEach(highlight);
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observer.observe(document.body, { childList: true, subtree: true });
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} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
              Skip to content
              Tracking Issue for x87_target_feature #150261
              Open
              Open
              Tracking Issue for x87_target_feature#150261
              Labels
              A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
              Description
              @RalfJung
              RalfJung
              opened on Dec 22, 2025
              This is a tracking issue for x87_target_feature, the x87 target feature on x86.
              See #44839 for discussion from before this feature got its own tracking issue.
              About tracking issues
              Tracking issues are used to record the overall progress of implementation.
              
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
              
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
              
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
              
Discussion comments will get marked as off-topic or deleted.
              
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
              Steps
              Unresolved Questions
              none at the moment
              Implementation history
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                Type
                No type
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
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(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
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var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
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});
}
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observer.observe(document.body, { childList: true, subtree: true });
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(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
                  Skip to content
                  Tracking Issue for x87_target_feature #150261
                  Open
                  Open
                  Tracking Issue for x87_target_feature#150261
                  Labels
                  A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                  Description
                  @RalfJung
                  RalfJung
                  opened on Dec 22, 2025
                  This is a tracking issue for x87_target_feature, the x87 target feature on x86.
                  See #44839 for discussion from before this feature got its own tracking issue.
                  About tracking issues
                  Tracking issues are used to record the overall progress of implementation.
                  
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
                  
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
                  
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
                  
Discussion comments will get marked as off-topic or deleted.
                  
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
                  Steps
                  Unresolved Questions
                  none at the moment
                  Implementation history
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                    Type
                    No type
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
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function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
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lastUrl = location.href;
setTimeout(tryTheater, 500);
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})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
                      Skip to content
                      Tracking Issue for x87_target_feature #150261
                      Open
                      Open
                      Tracking Issue for x87_target_feature#150261
                      Labels
                      A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                      Description
                      @RalfJung
                      RalfJung
                      opened on Dec 22, 2025
                      This is a tracking issue for x87_target_feature, the x87 target feature on x86.
                      See #44839 for discussion from before this feature got its own tracking issue.
                      About tracking issues
                      Tracking issues are used to record the overall progress of implementation.
                      
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
                      
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
                      
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
                      
Discussion comments will get marked as off-topic or deleted.
                      
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
                      Steps
                      Unresolved Questions
                      none at the moment
                      Implementation history
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                        Type
                        No type
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
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(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
                          Skip to content
                          Tracking Issue for x87_target_feature #150261
                          Open
                          Open
                          Tracking Issue for x87_target_feature#150261
                          Labels
                          A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                          Description
                          @RalfJung
                          RalfJung
                          opened on Dec 22, 2025
                          This is a tracking issue for x87_target_feature, the x87 target feature on x86.
                          See #44839 for discussion from before this feature got its own tracking issue.
                          About tracking issues
                          Tracking issues are used to record the overall progress of implementation.
                          
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
                          
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
                          
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
                          
Discussion comments will get marked as off-topic or deleted.
                          
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
                          Steps
                          Unresolved Questions
                          none at the moment
                          Implementation history
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                            Type
                            No type
                            Projects
                            No projects
                              Milestone
                              No milestone
                              Relationships
                              None yet
                              Development
                              No branches or pull requests
                              Issue actions
                              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
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var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
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/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
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filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
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::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
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::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
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var style = document.getElementById('universal-dark-mode-style');
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}
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document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
Tracking Issue for x87_target_feature · Issue #150261 · rust-lang/rust · GitHub
                              Skip to content
                              Tracking Issue for x87_target_feature #150261
                              Open
                              Open
                              Tracking Issue for x87_target_feature#150261
                              Labels
                              A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                              Description
                              @RalfJung
                              RalfJung
                              opened on Dec 22, 2025
                              This is a tracking issue for x87_target_feature, the x87 target feature on x86.
                              See #44839 for discussion from before this feature got its own tracking issue.
                              About tracking issues
                              Tracking issues are used to record the overall progress of implementation.
                              
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
                              
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
                              
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.
                              
Discussion comments will get marked as off-topic or deleted.
                              
Repeated discussions on the tracking issue may lead to the tracking issue getting locked.
                              Steps
                              Unresolved Questions
                              none at the moment
                              Implementation history
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                A-target-featureArea: Enabling/disabling target features like AVX, Neon, etc.C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
                                Type
                                No type
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions