diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/pr34349.ll | 27 |
2 files changed, 28 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index 39d1dfe27a0..cda2ce6c91c 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -426,7 +426,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, return I->getOperand(1); // Otherwise just compute the known bits of the result. - bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoUnsignedWrap(); + bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); Known = KnownBits::computeForAddSub(I->getOpcode() == Instruction::Add, NSW, LHSKnown, RHSKnown); break; diff --git a/llvm/test/Transforms/InstCombine/pr34349.ll b/llvm/test/Transforms/InstCombine/pr34349.ll new file mode 100644 index 00000000000..b88f77a4c86 --- /dev/null +++ b/llvm/test/Transforms/InstCombine/pr34349.ll @@ -0,0 +1,27 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +;RUN: opt -instcombine -S %s | FileCheck %s + +define i8 @fast_div_201(i8 %p) { +; CHECK-LABEL: @fast_div_201( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[V3:%.*]] = zext i8 [[P:%.*]] to i16 +; CHECK-NEXT: [[V4:%.*]] = mul nuw nsw i16 [[V3]], 71 +; CHECK-NEXT: [[V5:%.*]] = lshr i16 [[V4]], 8 +; CHECK-NEXT: [[V6:%.*]] = trunc i16 [[V5]] to i8 +; CHECK-NEXT: [[V7:%.*]] = sub i8 [[P]], [[V6]] +; CHECK-NEXT: [[V8:%.*]] = lshr i8 [[V7]], 1 +; CHECK-NEXT: [[V13:%.*]] = add nuw i8 [[V8]], [[V6]] +; CHECK-NEXT: [[V14:%.*]] = lshr i8 [[V13]], 7 +; CHECK-NEXT: ret i8 [[V14]] +; +entry: + %v3 = zext i8 %p to i16 + %v4 = mul i16 %v3, 71 + %v5 = lshr i16 %v4, 8 + %v6 = trunc i16 %v5 to i8 + %v7 = sub i8 %p, %v6 + %v8 = lshr i8 %v7, 1 + %v13 = add i8 %v6, %v8 + %v14 = lshr i8 %v13, 7 + ret i8 %v14 +} |
