diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -3965,6 +3965,15 @@ if (match(FalseVal, isRotate) && TrueVal == X && CmpLHS == ShAmt && Pred == ICmpInst::ICMP_EQ) return FalseVal; + + // X == 0 ? abs(X) : -abs(X) --> -abs(X) + // X == 0 ? -abs(X) : abs(X) --> abs(X) + if (match(TrueVal, m_Intrinsic(m_Value(X))) && + match(FalseVal, m_Neg(m_Intrinsic(m_Specific(X))))) + return FalseVal; + if (match(TrueVal, m_Neg(m_Intrinsic(m_Value(X)))) && + match(FalseVal, m_Intrinsic(m_Specific(X)))) + return FalseVal; } // Check for other compares that behave like bit test. diff --git a/llvm/test/Transforms/InstSimplify/abs_intrinsic.ll b/llvm/test/Transforms/InstSimplify/abs_intrinsic.ll --- a/llvm/test/Transforms/InstSimplify/abs_intrinsic.ll +++ b/llvm/test/Transforms/InstSimplify/abs_intrinsic.ll @@ -205,10 +205,7 @@ define i32 @select_abs_of_abs_eq(i32 %x) { ; CHECK-LABEL: @select_abs_of_abs_eq( ; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[X:%.*]], i1 false) -; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[ABS]] -; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[X]], 0 -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32 [[NEG]], i32 [[ABS]] -; CHECK-NEXT: ret i32 [[SEL]] +; CHECK-NEXT: ret i32 [[ABS]] ; %abs = call i32 @llvm.abs.i32(i32 %x, i1 false) %neg = sub i32 0, %abs @@ -220,10 +217,7 @@ define i32 @select_abs_of_abs_ne(i32 %x) { ; CHECK-LABEL: @select_abs_of_abs_ne( ; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[X:%.*]], i1 false) -; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[ABS]] -; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[X]], 0 -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32 [[ABS]], i32 [[NEG]] -; CHECK-NEXT: ret i32 [[SEL]] +; CHECK-NEXT: ret i32 [[ABS]] ; %abs = call i32 @llvm.abs.i32(i32 %x, i1 false) %neg = sub i32 0, %abs @@ -236,9 +230,7 @@ ; CHECK-LABEL: @select_nabs_of_abs_eq( ; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[X:%.*]], i1 false) ; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[ABS]] -; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[X]], 0 -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32 [[ABS]], i32 [[NEG]] -; CHECK-NEXT: ret i32 [[SEL]] +; CHECK-NEXT: ret i32 [[NEG]] ; %abs = call i32 @llvm.abs.i32(i32 %x, i1 false) %neg = sub i32 0, %abs @@ -251,9 +243,7 @@ ; CHECK-LABEL: @select_nabs_of_abs_ne( ; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[X:%.*]], i1 false) ; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[ABS]] -; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[X]], 0 -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32 [[NEG]], i32 [[ABS]] -; CHECK-NEXT: ret i32 [[SEL]] +; CHECK-NEXT: ret i32 [[NEG]] ; %abs = call i32 @llvm.abs.i32(i32 %x, i1 false) %neg = sub i32 0, %abs