[llvm] 340ae45 - [InstCombine] use isKnownNonNegative() for readability; NFCI

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2022-10-16T10:59:56-04:00
New Revision: 340ae45be06ae663e73edbee3f942f5dcd13c58e

URL: https://github.com/llvm/llvm-project/commit/340ae45be06ae663e73edbee3f942f5dcd13c58e
DIFF: https://github.com/llvm/llvm-project/commit/340ae45be06ae663e73edbee3f942f5dcd13c58e.diff

LOG: [InstCombine] use isKnownNonNegative() for readability; NFCI

This should be functionally equivalent - both calls are thin
wrappers around computeKnownBits(). We'll probably want to use
known-bits directly in follow-up patches because that could
determine "exact" for example (see issue #58348).

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index cc90ded72f585..b98e6736ccf94 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -1332,12 +1332,9 @@ Instruction *InstCombinerImpl::visitSDiv(BinaryOperator &I) {
                               ConstantInt::getAllOnesValue(Ty));
   }
 
-  // If the sign bits of both operands are zero (i.e. we can prove they are
-  // unsigned inputs), turn this into a udiv.
-  APInt Mask(APInt::getSignMask(Ty->getScalarSizeInBits()));
-  if (MaskedValueIsZero(Op0, Mask, 0, &I)) {
-    if (MaskedValueIsZero(Op1, Mask, 0, &I)) {
-      // X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
+  if (isKnownNonNegative(Op0, DL, 0, &AC, &I, &DT)) {
+    // If both operands are unsigned, turn this into a udiv.
+    if (isKnownNonNegative(Op1, DL, 0, &AC, &I, &DT)) {
       auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
       BO->setIsExact(I.isExact());
       return BO;