diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -2670,9 +2670,9 @@ return isKnownNonZero(I->getOperand(0), Depth, Q); case Instruction::Shl: { - // shl nuw can't remove any non-zero bits. + // shl nsw/nuw can't remove any non-zero bits. const OverflowingBinaryOperator *BO = cast(V); - if (Q.IIQ.hasNoUnsignedWrap(BO)) + if (Q.IIQ.hasNoUnsignedWrap(BO) || Q.IIQ.hasNoSignedWrap(BO)) return isKnownNonZero(I->getOperand(0), Depth, Q); // shl X, Y != 0 if X is odd. Note that the value of the shift is undefined diff --git a/llvm/test/Analysis/ValueTracking/known-non-zero.ll b/llvm/test/Analysis/ValueTracking/known-non-zero.ll --- a/llvm/test/Analysis/ValueTracking/known-non-zero.ll +++ b/llvm/test/Analysis/ValueTracking/known-non-zero.ll @@ -227,9 +227,7 @@ ; CHECK-LABEL: @shl_non_zero_nsw( ; CHECK-NEXT: [[NZ:%.*]] = icmp ne i8 [[S:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[NZ]]) -; CHECK-NEXT: [[V:%.*]] = shl nsw i8 [[S]], [[CNT:%.*]] -; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[V]], 0 -; CHECK-NEXT: ret i1 [[R]] +; CHECK-NEXT: ret i1 false ; %nz = icmp ne i8 %s, 0 call void @llvm.assume(i1 %nz)