Remove UnsafeFPMath in visitFADDForFMACombine

Author: paperchalice

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -16914,8 +16914,7 @@ SDValue DAGCombiner::visitFADDForFMACombine(SDNode *N) {
   // fadd (G, (fma A, B, (fma (C, D, (fmul (E, F)))))) -->
   // fma A, B, (fma C, D, fma (E, F, G)).
   // This requires reassociation because it changes the order of operations.
-  bool CanReassociate =
-      Options.UnsafeFPMath || N->getFlags().hasAllowReassociation();
+  bool CanReassociate = N->getFlags().hasAllowReassociation();
   if (CanReassociate) {
     SDValue FMA, E;
     if (isFusedOp(N0) && N0.hasOneUse()) {
@@ -18087,8 +18086,7 @@ template <class MatchContextClass> SDValue DAGCombiner::visitFMA(SDNode *N) {
       return matcher.getNode(ISD::FMA, DL, VT, NegN0, NegN1, N2);
   }
 
-  // FIXME: use fast math flags instead of Options.UnsafeFPMath
-  // TODO: Finally migrate away from global TargetOptions.
+  // FIXME: Finally migrate away from global TargetOptions.
   if (Options.AllowFPOpFusion == FPOpFusion::Fast ||
       (Options.NoNaNsFPMath && Options.NoInfsFPMath) ||
       (N->getFlags().hasNoNaNs() && N->getFlags().hasNoInfs())) {
@@ -18112,8 +18110,7 @@ template <class MatchContextClass> SDValue DAGCombiner::visitFMA(SDNode *N) {
      !DAG.isConstantFPBuildVectorOrConstantFP(N1))
     return matcher.getNode(ISD::FMA, DL, VT, N1, N0, N2);
 
-  bool CanReassociate =
-      Options.UnsafeFPMath || N->getFlags().hasAllowReassociation();
+  bool CanReassociate = N->getFlags().hasAllowReassociation();
   if (CanReassociate) {
     // (fma x, c1, (fmul x, c2)) -> (fmul x, c1+c2)
     if (matcher.match(N2, ISD::FMUL) && N0 == N2.getOperand(0) &&

llvm/test/CodeGen/NVPTX/fma-assoc.ll

@@ -20,10 +20,10 @@ define ptx_device float @t1_f32(float %x, float %y, float %z,
 ; CHECK-UNSAFE-NEXT:    st.param.b32 [func_retval0], %r7;
 ; CHECK-UNSAFE-NEXT:    ret;
                                 float %u, float %v) {
-  %a = fmul float %x, %y
-  %b = fmul float %u, %v
-  %c = fadd float %a, %b
-  %d = fadd float %c, %z
+  %a = fmul reassoc float %x, %y
+  %b = fmul reassoc float %u, %v
+  %c = fadd reassoc float %a, %b
+  %d = fadd reassoc float %c, %z
   ret float %d
 }
 
@@ -43,10 +43,10 @@ define ptx_device double @t1_f64(double %x, double %y, double %z,
 ; CHECK-UNSAFE-NEXT:    st.param.b64 [func_retval0], %rd7;
 ; CHECK-UNSAFE-NEXT:    ret;
                                  double %u, double %v) {
-  %a = fmul double %x, %y
-  %b = fmul double %u, %v
-  %c = fadd double %a, %b
-  %d = fadd double %c, %z
+  %a = fmul reassoc double %x, %y
+  %b = fmul reassoc double %u, %v
+  %c = fadd reassoc double %a, %b
+  %d = fadd reassoc double %c, %z
   ret double %d
 }