(FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
return Op0;
- // fsub 0, (fsub -0.0, X) ==> X
+ // fsub -0.0, (fsub -0.0, X) ==> X
Value *X;
- if (match(Op0, m_AnyZero())) {
- if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
- return X;
- if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
- return X;
- }
+ if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
+ return X;
+
+ // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
+ if (FMF.noSignedZeros() && match(Op0, m_NegZero()) &&
+ match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
+ return X;
// fsub nnan x, x ==> 0.0
if (FMF.noNaNs() && Op0 == Op1)
; RUN: opt < %s -instsimplify -S | FileCheck %s
-; fsub 0, (fsub 0, X) ==> X
-; CHECK-LABEL: @fsub_0_0_x(
-define float @fsub_0_0_x(float %a) {
+; fsub -0.0, (fsub -0.0, X) ==> X
+; CHECK-LABEL: @fsub_-0_-0_x(
+define float @fsub_-0_-0_x(float %a) {
%t1 = fsub float -0.0, %a
%ret = fsub float -0.0, %t1
ret float %ret
}
+; fsub 0.0, (fsub -0.0, X) != X
+; CHECK-LABEL: @fsub_0_-0_x(
+define float @fsub_0_-0_x(float %a) {
+ %t1 = fsub float 0.0, %a
+ %ret = fsub float -0.0, %t1
+
+; CHECK-NOT: ret float %a
+ ret float %ret
+}
+
+; fsub -0.0, (fsub 0.0, X) != X
+; CHECK-LABEL: @fsub_-0_0_x(
+define float @fsub_-0_0_x(float %a) {
+ %t1 = fsub float -0.0, %a
+ %ret = fsub float 0.0, %t1
+
+; CHECK-NOT: ret float %a
+ ret float %ret
+}
+
; fsub X, 0 ==> X
; CHECK-LABEL: @fsub_x_0(
define float @fsub_x_0(float %a) {