[PATCH] D62544: [InstCombine] Optimize always overflowing signed saturating add/sub

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp:2073-2074
+        unsigned BitWidth = Ty->getScalarSizeInBits();
+        APInt Min = SI->isSigned() ? APInt::getSignedMinValue(BitWidth)
+                                   : APInt::getMinValue(BitWidth);
+        return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Min));
----------------
Can you use `APSInt::getMinValue(BitWidth, !SI->isSigned())` instead?


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp:2079-2080
+        unsigned BitWidth = Ty->getScalarSizeInBits();
+        APInt Max = SI->isSigned() ? APInt::getSignedMaxValue(BitWidth)
+                                   : APInt::getMaxValue(BitWidth);
+        return replaceInstUsesWith(*SI, ConstantInt::get(Ty, Max));
----------------
Same


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62544/new/

https://reviews.llvm.org/D62544