AddToWorklist(RV.getNode());
return DAG.getNode(ISD::FMUL, DL, VT, N0, RV);
}
+ } else if (N1.getOpcode() == ISD::FMUL) {
+ // Look through an FMUL. Even though this won't remove the FDIV directly,
+ // it's still worthwhile to get rid of the FSQRT if possible.
+ SDValue SqrtOp;
+ SDValue OtherOp;
+ if (N1.getOperand(0).getOpcode() == ISD::FSQRT) {
+ SqrtOp = N1.getOperand(0);
+ OtherOp = N1.getOperand(1);
+ } else if (N1.getOperand(1).getOpcode() == ISD::FSQRT) {
+ SqrtOp = N1.getOperand(1);
+ OtherOp = N1.getOperand(0);
+ }
+ if (SqrtOp.getNode()) {
+ // We found a FSQRT, so try to make this fold:
+ // x / (y * sqrt(z)) -> x * (rsqrt(z) / y)
+ if (SDValue RV = BuildRsqrtEstimate(SqrtOp.getOperand(0))) {
+ AddToWorklist(RV.getNode());
+ RV = DAG.getNode(ISD::FDIV, SDLoc(N1), VT, RV, OtherOp);
+ AddToWorklist(RV.getNode());
+ return DAG.getNode(ISD::FMUL, DL, VT, N0, RV);
+ }
+ }
}
// Fold into a reciprocal estimate and multiply instead of a real divide.
; CHECK-SAFE: blr
}
+; Recognize that this is rsqrt(a) * rcp(b) * c,
+; not 1 / ( 1 / sqrt(a)) * rcp(b) * c.
+define float @rsqrt_fmul(float %a, float %b, float %c) {
+ %x = call float @llvm.sqrt.f32(float %a)
+ %y = fmul float %x, %b
+ %z = fdiv float %c, %y
+ ret float %z
+
+; CHECK: @rsqrt_fmul
+; CHECK-DAG: frsqrtes
+; CHECK-DAG: fres
+; CHECK-DAG: fnmsubs
+; CHECK-DAG: fmuls
+; CHECK-DAG: fnmsubs
+; CHECK-DAG: fmadds
+; CHECK-DAG: fmadds
+; CHECK: fmuls
+; CHECK-NEXT: fmuls
+; CHECK-NEXT: fmuls
+; CHECK-NEXT: blr
+
+; CHECK-SAFE: @rsqrt_fmul
+; CHECK-SAFE: fsqrts
+; CHECK-SAFE: fmuls
+; CHECK-SAFE: fdivs
+; CHECK-SAFE: blr
+}
+
define <4 x float> @hoo(<4 x float> %a, <4 x float> %b) nounwind {
%x = call <4 x float> @llvm.sqrt.v4f32(<4 x float> %b)
%r = fdiv <4 x float> %a, %x