[PATCH] D98659: [MachineCopyPropagation] Do more backward copy propagations

[yshui via Phabricator via llvm-commits]

yshui added inline comments.


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Comment at: llvm/lib/CodeGen/MachineCopyPropagation.cpp:283-284
 
-  MachineInstr *findAvailBackwardCopy(MachineInstr &I, MCRegister Reg,
-                                      const TargetRegisterInfo &TRI) {
+  std::pair<MachineInstr *, SmallVector<MachineInstr *>>
+  findAvailBackwardCopy(MachineInstr &I, MCRegister Reg,
+                        const TargetRegisterInfo &TRI) {
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jmorse wrote:
> Performance nit -- is it safe to return a `SmallVector *` in the pair? That avoids needless copying and potential allocations.
I don't see a problem with this. Will update.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D98659/new/

https://reviews.llvm.org/D98659