[PATCH] D42402: [GISel]: Eliminate redundant copies b/w VRegs of same regclass at the end of InstructionSelection

[Quentin Colombet via Phabricator via llvm-commits]

qcolombet added a comment.

Sounds like a good thing to do.

One comment inline.



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Comment at: lib/CodeGen/GlobalISel/InstructionSelect.cpp:194
+    }
+  }
+
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Instead of having another pass through the IR for this, could we do it while we do the ISel loop?

Meaning, if the register banks match, push the RC to the def and let constraint operand create a new copy if need be.
I would expect this to be more efficient in term of compile time, but we would need to check.


https://reviews.llvm.org/D42402