[PATCH] D153838: [MCP] Optimize copies from undef
Pierre van Houtryve via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 27 22:55:40 PDT 2023
Pierre-vh marked 2 inline comments as done.
Pierre-vh added inline comments.
================
Comment at: llvm/lib/CodeGen/MachineCopyPropagation.cpp:486-487
+ if (!CopyOperands->Source->isUndef()) {
+ PrevCopy->getOperand(PrevCopyOperands->Source->getOperandNo())
+ .setIsUndef(false);
+ }
----------------
arsenm wrote:
> Pierre-vh wrote:
> > foad wrote:
> > > Doesn't `PrevCopyOperands->Source->setIsUndef(false)` work?
> > The reference to the MachineOperand is const, unfortunately
> You can change that?
It's `struct DestSourcePair`, it's sometimes initialized from `const MachineInstr` so I can't just remove the const qualifier there.
An alternative may be to create a copy of that struct and name it `MutableDestSourcePair`, and use it where relevant.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D153838/new/
https://reviews.llvm.org/D153838
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