[PATCH] D43349: [InstCombine] Make SimplifyDemandedUseBits handle PhiNode

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp:473
 
+      if (SimplifyDemandedBits(I, 0, DemandedMaskIn, Known, Depth + 1))
+        return I;
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This seems unrelated or at least unexplained.


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Comment at: lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp:479
       if (cast<LShrOperator>(I)->isExact())
         DemandedMaskIn.setLowBits(ShiftAmt);
 
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DemandedMaskIn isn't used after this.


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Comment at: lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp:517
 
+      if (SimplifyDemandedBits(I, 0, DemandedMaskIn, Known, Depth + 1))
+        return I;
----------------
This as well?


https://reviews.llvm.org/D43349