JIT: Reset last-use flag for live defs in liveness #121553
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We would leave `GTF_VAR_DEATH` set if it had already been set on the node from a previous run of liveness.
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Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch |
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jakobbotsch
November 12, 2025 15:15
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Pull Request Overview
This PR fixes issue #121552 by ensuring the GTF_VAR_DEATH flag is properly reset during liveness analysis when it may run multiple times. The fix addresses a case where the flag could remain set from a previous liveness analysis run, leading to incorrect behavior.
Key Changes:
- Added code to clear
GTF_VAR_DEATHflag infgComputeLifeTrackedLocalDefwhen a variable is determined to be live - This mirrors the existing pattern already present in the companion function
fgComputeLifeTrackedLocalUse
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PTAL @dotnet/jit-contrib. We have this kind of flag clearing in other places in liveness, but looks like this place missed it. |
AndyAyersMS
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Nov 12, 2025
This was referenced Nov 12, 2025
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/ba-g Timeouts |
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We would leave
GTF_VAR_DEATHset if it had already been set on the node from a previous run of liveness.In the issue that resulted in
TreeLifeUpdatercomputing the wrong liveness set resulting in us not saving a live local around a suspension.Fix #121552