diff options
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/shift.ll | 24 |
2 files changed, 11 insertions, 19 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 4a80558dd1b..c15f649e9c4 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1162,7 +1162,11 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0, return Constant::getNullValue(Op0->getType()); // X shift by 0 -> X - if (match(Op1, m_Zero())) + // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones + // would be poison. + Value *X; + if (match(Op1, m_Zero()) || + (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))) return Op0; // Fold undefined shifts. diff --git a/llvm/test/Transforms/InstSimplify/shift.ll b/llvm/test/Transforms/InstSimplify/shift.ll index ad572a1dbe3..d080cbc6212 100644 --- a/llvm/test/Transforms/InstSimplify/shift.ll +++ b/llvm/test/Transforms/InstSimplify/shift.ll @@ -123,9 +123,7 @@ define <3 x i8> @ashr_all_ones_vec_with_undef_elts(<3 x i8> %x, <3 x i8> %y) { define i8 @lshr_by_sext_bool(i1 %x, i8 %y) { ; CHECK-LABEL: @lshr_by_sext_bool( -; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 -; CHECK-NEXT: [[R:%.*]] = lshr i8 [[Y:%.*]], [[S]] -; CHECK-NEXT: ret i8 [[R]] +; CHECK-NEXT: ret i8 [[Y:%.*]] ; %s = sext i1 %x to i8 %r = lshr i8 %y, %s @@ -134,9 +132,7 @@ define i8 @lshr_by_sext_bool(i1 %x, i8 %y) { define <2 x i8> @lshr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { ; CHECK-LABEL: @lshr_by_sext_bool_vec( -; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> -; CHECK-NEXT: [[R:%.*]] = lshr <2 x i8> [[Y:%.*]], [[S]] -; CHECK-NEXT: ret <2 x i8> [[R]] +; CHECK-NEXT: ret <2 x i8> [[Y:%.*]] ; %s = sext <2 x i1> %x to <2 x i8> %r = lshr <2 x i8> %y, %s @@ -145,9 +141,7 @@ define <2 x i8> @lshr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { define i8 @ashr_by_sext_bool(i1 %x, i8 %y) { ; CHECK-LABEL: @ashr_by_sext_bool( -; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 -; CHECK-NEXT: [[R:%.*]] = ashr i8 [[Y:%.*]], [[S]] -; CHECK-NEXT: ret i8 [[R]] +; CHECK-NEXT: ret i8 [[Y:%.*]] ; %s = sext i1 %x to i8 %r = ashr i8 %y, %s @@ -156,9 +150,7 @@ define i8 @ashr_by_sext_bool(i1 %x, i8 %y) { define <2 x i8> @ashr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { ; CHECK-LABEL: @ashr_by_sext_bool_vec( -; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> -; CHECK-NEXT: [[R:%.*]] = ashr <2 x i8> [[Y:%.*]], [[S]] -; CHECK-NEXT: ret <2 x i8> [[R]] +; CHECK-NEXT: ret <2 x i8> [[Y:%.*]] ; %s = sext <2 x i1> %x to <2 x i8> %r = ashr <2 x i8> %y, %s @@ -167,9 +159,7 @@ define <2 x i8> @ashr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { define i8 @shl_by_sext_bool(i1 %x, i8 %y) { ; CHECK-LABEL: @shl_by_sext_bool( -; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 -; CHECK-NEXT: [[R:%.*]] = shl i8 [[Y:%.*]], [[S]] -; CHECK-NEXT: ret i8 [[R]] +; CHECK-NEXT: ret i8 [[Y:%.*]] ; %s = sext i1 %x to i8 %r = shl i8 %y, %s @@ -178,9 +168,7 @@ define i8 @shl_by_sext_bool(i1 %x, i8 %y) { define <2 x i8> @shl_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { ; CHECK-LABEL: @shl_by_sext_bool_vec( -; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> -; CHECK-NEXT: [[R:%.*]] = shl <2 x i8> [[Y:%.*]], [[S]] -; CHECK-NEXT: ret <2 x i8> [[R]] +; CHECK-NEXT: ret <2 x i8> [[Y:%.*]] ; %s = sext <2 x i1> %x to <2 x i8> %r = shl <2 x i8> %y, %s |
