[PATCH] D150855: MachineCombiner: consider all uses in getLatency()

[Sergei Barannikov via Phabricator via llvm-commits]

barannikov88 added inline comments.


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Comment at: llvm/lib/CodeGen/MachineCombiner.cpp:286
+            NewRoot, NewRoot->findRegisterDefOperandIdx(MO.getReg()), &UseInstr,
+            MO.getOperandNo());
+      } else {
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barannikov88 wrote:
> barannikov88 wrote:
> > This now gets the operand number of the defining instruction. We need the operand number of the using instruction here; it is likely to be different.
> > Please consider using `use_nodbg_operands`. You can get the UseInstr from it by calling `UseMO.getParent()`.
> > 
> (FWIW `NewRoot->findRegisterDefOperandIdx(MO.getReg())` could probably also be simplified to `MO.getOperandNo()`, but I'm sure. Perhaps there was a reason for not doing so. This is not a change request.)
> 
~~but I'm sure~~
but I'm not sure


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  https://reviews.llvm.org/D150855/new/

https://reviews.llvm.org/D150855