[PATCH] D107476: [ARM] Define ComplexPatternFuncMutatesDAG

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added inline comments.


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Comment at: llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp:83
+  /// canExtractShiftFromMul perform mul to shift mutations.
+  bool ComplexPatternFuncMutatesDAG() const override {
+    return true;
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Nice find. Bit of an "obscure" hook, doesn't seem to be documented very well. But I guess it will eventually call `canExtractShiftFromMul`, perhaps you can clarify that a little bit in the comment.


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Comment at: llvm/test/CodeGen/ARM/shifter_operand.ll:520
+  %indvar.next25.3 = add i32 %indvar24, 4
+  br label %for.cond2.preheader
+
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You already mentioned the test case being a bit big, but do we need a loop? I guess you do, but that's unclear to me.

If it can't be reduced, can you precommit the test? Then we can see the diff here.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D107476/new/

https://reviews.llvm.org/D107476