[DebugInfo][InstrRef] Treat ORRWrr as a copy instr (#123102) #9886
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The insturction selector uses the `MachineFunction::copySalvageSSA` function to insert `DBG_PHIs` or identify a defining instruction for a copy-like instruction when finalizing Instruction References. AArch64 has the ORR instruction which is a logical OR with the variants ORRWrr which refers to a register to register variant, and ORRWrs which is a register to a shifted register variant. An ORRWrs where the shift amount is 0, and the zero register ($wzr) is used is considered a copy, for example: `$w0 = ORRWrs $wzr, killed $w3, 0` However an ORRWrr with a zero register is not considered a copy `$w0 = ORRWrr $wzr, killed $w3` This causes an issue in the livedebugvalues pass because in aarch64-isel the instruction is the ORRWrr variant, but is then changed to the ORRWrs variant before the livedebugvalues pass. This causes a mismatch between the two passes which leads to a crash in the livedebugvalues pass. This patch fixes the issue. (cherry picked from commit ee1c852)
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@swift-ci please test Linux |
adrian-prantl
approved these changes
Jan 29, 2025
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The insturction selector uses the
MachineFunction::copySalvageSSAfunction to insertDBG_PHIsor identify a defining instruction for a copy-like instruction when finalizing Instruction References.AArch64 has the ORR instruction which is a logical OR with the variants ORRWrr which refers to a register to register variant, and ORRWrs which is a register to a shifted register variant.
An ORRWrs where the shift amount is 0, and the zero register ($wzr) is used is considered a copy, for example:
$w0 = ORRWrs $wzr, killed $w3, 0However an ORRWrr with a zero register is not considered a copy
$w0 = ORRWrr $wzr, killed $w3This causes an issue in the livedebugvalues pass because in aarch64-isel the instruction is the ORRWrr variant, but is then changed to the ORRWrs variant before the livedebugvalues pass.
This causes a mismatch between the two passes which leads to a crash in the livedebugvalues pass.
This patch fixes the issue.
(cherry picked from commit ee1c852)