return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0,
GetNegatedExpression(N1, DAG, LegalOperations));
+ // If 'unsafe math' is enabled, fold
+ // (fsub x, (fadd x, y)) -> (fneg y) &
+ // (fsub x, (fadd y, x)) -> (fneg y)
+ if (DAG.getTarget().Options.UnsafeFPMath) {
+ if (N1.getOpcode() == ISD::FADD) {
+ SDValue N10 = N1->getOperand(0);
+ SDValue N11 = N1->getOperand(1);
+
+ if (N10 == N0 && isNegatibleForFree(N11, LegalOperations, TLI,
+ &DAG.getTarget().Options))
+ return GetNegatedExpression(N11, DAG, LegalOperations);
+ else if (N11 == N0 && isNegatibleForFree(N10, LegalOperations, TLI,
+ &DAG.getTarget().Options))
+ return GetNegatedExpression(N10, DAG, LegalOperations);
+ }
+ }
+
return SDValue();
}