JIT: Remove BBF_RUN_RARELY#118147
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amanasifkhalid merged 7 commits intodotnet:mainfrom Jul 29, 2025
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Pull Request Overview
This PR removes the BBF_RUN_RARELY flag from the JIT compiler and replaces its functionality by comparing the block's execution weight to BB_ZERO_WEIGHT. This simplifies the codebase by eliminating redundant flag management while maintaining the same logical behavior for identifying rarely-run blocks.
Key changes:
- Remove
BBF_RUN_RARELYflag definition and all its usages - Update
isRunRarely()method to checkbbWeight == BB_ZERO_WEIGHTinstead of the flag - Remove flag maintenance code that synchronized
BBF_RUN_RARELYwith zero weights - Introduce
bbSetRunRarely()method calls where appropriate
Reviewed Changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| src/coreclr/jit/block.h | Removes BBF_RUN_RARELY flag definition, updates isRunRarely() implementation, removes flag synchronization in weight-setting methods |
| src/coreclr/jit/optimizer.cpp | Removes BBF_RUN_RARELY flag removal/setting code in weight management functions |
| src/coreclr/jit/importer.cpp | Replaces explicit weight and flag setting with bbSetRunRarely() call and removes flag copying |
| src/coreclr/jit/fgprofile.cpp | Removes flag synchronization when setting block weights |
| src/coreclr/jit/fgopt.cpp | Updates profile weight checks to use method calls instead of flag checks, removes flag setting |
| src/coreclr/jit/fginline.cpp | Removes BBF_RUN_RARELY exclusion when copying block flags |
| src/coreclr/jit/fgdiagnostic.cpp | Removes BBF_RUN_RARELY from debug output and validation |
| src/coreclr/jit/block.cpp | Removes BBF_RUN_RARELY from debug flag display |
| src/coreclr/jit/async.cpp | Replaces weight inheritance with direct bbSetRunRarely() call |
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Co-authored-by: Copilot <[email protected]>
…alid/runtime into remove-bbf-run-rarely
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@dotnet/jit-contrib PTAL. No diffs. Thanks! |
EgorBo
approved these changes
Jul 29, 2025
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Since every block is expected to have an execution count, compare this count to
BB_ZERO_WEIGHTto determine if the block is rarely-run rather than maintaining a flag to indicate it. Fixes #48778.