if (!isDefaultFPEnvironment(ExBehavior, Rounding))
return nullptr;
- // fsub nnan x, x ==> 0.0
- if (FMF.noNaNs() && Op0 == Op1)
- return Constant::getNullValue(Op0->getType());
+ if (FMF.noNaNs()) {
+ // fsub nnan x, x ==> 0.0
+ if (Op0 == Op1)
+ return Constant::getNullValue(Op0->getType());
+
+ // With nnan: {+/-}Inf - X --> {+/-}Inf
+ if (match(Op0, m_Inf()))
+ return Op0;
+
+ // With nnan: X - {+/-}Inf --> {-/+}Inf
+ if (match(Op1, m_Inf()))
+ return foldConstant(Instruction::FNeg, Op1, Q);
+ }
// Y - (Y - X) --> X
// (X + Y) - Y --> X
define double @fsub_nnan_inf_op0(double %x) {
; CHECK-LABEL: @fsub_nnan_inf_op0(
-; CHECK-NEXT: [[R:%.*]] = fsub nnan double 0x7FF0000000000000, [[X:%.*]]
-; CHECK-NEXT: ret double [[R]]
+; CHECK-NEXT: ret double 0x7FF0000000000000
;
%r = fsub nnan double 0x7ff0000000000000, %x
ret double %r
}
+; flip sign
+
define double @fsub_nnan_inf_op1(double %x) {
; CHECK-LABEL: @fsub_nnan_inf_op1(
-; CHECK-NEXT: [[R:%.*]] = fsub nnan double [[X:%.*]], 0x7FF0000000000000
-; CHECK-NEXT: ret double [[R]]
+; CHECK-NEXT: ret double 0xFFF0000000000000
;
%r = fsub nnan double %x, 0x7ff0000000000000
ret double %r
define <2 x double> @fsub_nnan_neginf_op0(<2 x double> %x) {
; CHECK-LABEL: @fsub_nnan_neginf_op0(
-; CHECK-NEXT: [[R:%.*]] = fsub nnan <2 x double> <double 0xFFF0000000000000, double poison>, [[X:%.*]]
-; CHECK-NEXT: ret <2 x double> [[R]]
+; CHECK-NEXT: ret <2 x double> <double 0xFFF0000000000000, double poison>
;
%r = fsub nnan <2 x double> <double 0xfff0000000000000, double poison>, %x
ret <2 x double> %r
}
+; flip sign
+
define double @fsub_nnan_neginf_op1(double %x) {
; CHECK-LABEL: @fsub_nnan_neginf_op1(
-; CHECK-NEXT: [[R:%.*]] = fsub nnan double [[X:%.*]], 0xFFF0000000000000
-; CHECK-NEXT: ret double [[R]]
+; CHECK-NEXT: ret double 0x7FF0000000000000
;
%r = fsub nnan double %x, 0xfff0000000000000
ret double %r
}
+; negative test - requires nnan
+
define double @fsub_inf_op0(double %x) {
; CHECK-LABEL: @fsub_inf_op0(
; CHECK-NEXT: [[R:%.*]] = fsub double 0x7FF0000000000000, [[X:%.*]]
ret double %r
}
-; TODO: Should simplify to inf.
-
define double @fsub_nnan_inf_op0(double %x) {
; CHECK-LABEL: @fsub_nnan_inf_op0(
-; CHECK-NEXT: [[R:%.*]] = fsub nnan double 0x7FF0000000000000, [[X:%.*]]
-; CHECK-NEXT: ret double [[R]]
+; CHECK-NEXT: ret double 0x7FF0000000000000
;
%r = fsub nnan double 0x7ff0000000000000, %x
ret double %r