[PATCH] D64393: [AMDGPU] Fix DPP combiner check for exec modification

[Valery Pykhtin via Phabricator via llvm-commits]

vpykhtin added a comment.
Herald added a subscriber: kerbowa.

I've found the case when execMayBeModifiedBeforeAnyUse randomly leads to a coredump, which is hard to debug. Most likely it's because an instruction beyond the end of a basic block is accessed. This means that the first loop calculates some instructions twice and I was wrong assuming use_nodbg_instructions doesn't repeat them. In fact there is no code in MachineRegisterInfo::verifyUseList that ensures that uses belonging to one instruction should be sequent in the use list nor the traces of such ordering can be found in MachineRegisterInfo::addRegOperandToUseList. I'm going to fix this code.


Repository:
  rL LLVM

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https://reviews.llvm.org/D64393