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

[Sergei Barannikov via Phabricator via llvm-commits]

barannikov88 added a comment.

In D150855#4352644 <https://reviews.llvm.org/D150855#4352644>, @artagnon wrote:

> There are no test changes, but Embench shows a minor improvement in one test.

Can this test be reduced and added to the review? I'm afraid this can't proceed without test coverage.



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Comment at: llvm/lib/CodeGen/MachineCombiner.cpp:286
+            NewRoot, NewRoot->findRegisterDefOperandIdx(MO.getReg()), &UseInstr,
+            MO.getOperandNo());
+      } else {
----------------
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()`.



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

https://reviews.llvm.org/D150855