[PATCH] D36395: [InstCombine] narrow rotate left/right patterns to eliminate zext/trunc (PR34046)

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: lib/Transforms/InstCombine/InstCombineCasts.cpp:484
+  Type *DestTy = Trunc.getType();
+  unsigned NarrowWidth = DestTy->getScalarSizeInBits();
+  if (NarrowWidth != *BitWidthC)
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Since we don't support vectors here. Should this be getIntegerBitWidth()?


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Comment at: lib/Transforms/InstCombine/InstCombineCasts.cpp:485
+  unsigned NarrowWidth = DestTy->getScalarSizeInBits();
+  if (NarrowWidth != *BitWidthC)
+    return nullptr;
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Could you have used m_SpecificInt in the matchers above? to avoid this separate check?


https://reviews.llvm.org/D36395