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[RISCV] Use tail agnostic policy for instructions with tied defs if the use operand is IMPLICIT_DEF.
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Authored by craig.topper on Jan 12 2021, 4:46 PM.

Details

Summary

The vcompress intrinsic is defined such that it requires a tail
undisturbed policy. This patch makes it so we can use the tail
agnostic policy if the user has passed vundefined to the dest
operand.

We need to do something similar for masked policy, but we need
annotation of which instructions use the mask policy first.

Not sure if this is sufficient for scheduling or if we'll need to
select different pseudos that don't have a tied def.

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Event Timeline

craig.topper created this revision.Jan 12 2021, 4:46 PM
craig.topper requested review of this revision.Jan 12 2021, 4:47 PM
Herald added a project: Restricted Project. · View Herald TranscriptJan 12 2021, 4:47 PM
Herald added a subscriber: MaskRay. · View Herald Transcript
evandro accepted this revision.Jan 15 2021, 6:32 PM
This revision is now accepted and ready to land.Jan 15 2021, 6:32 PM