Index: lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4818,7 +4818,7 @@
     case ISD::FMUL:
     case ISD::FDIV:
     case ISD::FREM:
-      if (getTarget().Options.UnsafeFPMath)
+      if (getTarget().Options.UnsafeFPMath || Flags.isFast())
         return N2;
       break;
     case ISD::MUL:
Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2769,6 +2769,10 @@
     Flags.setVectorReduction(true);
     LLVM_DEBUG(dbgs() << "Detected a reduction operation:" << I << "\n");
   }
+  // need Flags for Selection DAG decisions here
+  if (auto *FPMO = dyn_cast<FPMathOperator>(&I)) {
+    Flags.copyFMF(*FPMO);
+  }
 
   SDValue Op1 = getValue(I.getOperand(0));
   SDValue Op2 = getValue(I.getOperand(1));
Index: test/CodeGen/X86/fp-undef.ll
===================================================================
--- test/CodeGen/X86/fp-undef.ll
+++ test/CodeGen/X86/fp-undef.ll
@@ -6,28 +6,18 @@
 ; adding something here, you should probably add it there too.
 
 define float @fadd_undef_op0(float %x) {
-; STRICT-LABEL: fadd_undef_op0:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op0:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd float undef, %x
+; ANY-LABEL: fadd_undef_op0:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast float undef, %x
   ret float %r
 }
 
 define float @fadd_undef_op1(float %x) {
-; STRICT-LABEL: fadd_undef_op1:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op1:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd float %x, undef
+; ANY-LABEL: fadd_undef_op1:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast float %x, undef
   ret float %r
 }
 
@@ -35,46 +25,31 @@
 ; ANY-LABEL: fsub_undef_op0:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = fsub float undef, %x
+  %r = fsub fast float undef, %x
   ret float %r
 }
 
 define float @fsub_undef_op1(float %x) {
-; STRICT-LABEL: fsub_undef_op1:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    subss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fsub_undef_op1:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fsub float %x, undef
+; ANY-LABEL: fsub_undef_op1:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fsub fast float %x, undef
   ret float %r
 }
 
 define float @fmul_undef_op0(float %x) {
-; STRICT-LABEL: fmul_undef_op0:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op0:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul float undef, %x
+; ANY-LABEL: fmul_undef_op0:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast float undef, %x
   ret float %r
 }
 
 define float @fmul_undef_op1(float %x) {
-; STRICT-LABEL: fmul_undef_op1:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op1:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul float %x, undef
+; ANY-LABEL: fmul_undef_op1:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast float %x, undef
   ret float %r
 }
 
@@ -82,20 +57,15 @@
 ; ANY-LABEL: fdiv_undef_op0:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = fdiv float undef, %x
+  %r = fdiv fast float undef, %x
   ret float %r
 }
 
 define float @fdiv_undef_op1(float %x) {
-; STRICT-LABEL: fdiv_undef_op1:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    divss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fdiv_undef_op1:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fdiv float %x, undef
+; ANY-LABEL: fdiv_undef_op1:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fdiv fast float %x, undef
   ret float %r
 }
 
@@ -103,19 +73,15 @@
 ; ANY-LABEL: frem_undef_op0:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = frem float undef, %x
+  %r = frem fast float undef, %x
   ret float %r
 }
 
 define float @frem_undef_op1(float %x) {
-; STRICT-LABEL: frem_undef_op1:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    jmp fmodf # TAILCALL
-;
-; UNSAFE-LABEL: frem_undef_op1:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = frem float %x, undef
+; ANY-LABEL: frem_undef_op1:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = frem fast float %x, undef
   ret float %r
 }
 
@@ -135,14 +101,9 @@
 }
 
 define float @fadd_undef_op1_fast(float %x) {
-; STRICT-LABEL: fadd_undef_op1_fast:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op1_fast:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fadd_undef_op1_fast:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fadd fast float %x, undef
   ret float %r
 }
@@ -182,14 +143,9 @@
 }
 
 define float @fmul_undef_op1_fast(float %x) {
-; STRICT-LABEL: fmul_undef_op1_fast:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op1_fast:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fmul_undef_op1_fast:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fmul fast float %x, undef
   ret float %r
 }
@@ -224,13 +180,9 @@
 }
 
 define float @frem_undef_op1_fast(float %x) {
-; STRICT-LABEL: frem_undef_op1_fast:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    jmp fmodf # TAILCALL
-;
-; UNSAFE-LABEL: frem_undef_op1_fast:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: frem_undef_op1_fast:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = frem fast float %x, undef
   ret float %r
 }
@@ -238,15 +190,10 @@
 ; Constant folding - undef undef.
 
 define double @fadd_undef_undef(double %x) {
-; STRICT-LABEL: fadd_undef_undef:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addsd %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_undef:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd double undef, undef
+; ANY-LABEL: fadd_undef_undef:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast double undef, undef
   ret double %r
 }
 
@@ -254,20 +201,15 @@
 ; ANY-LABEL: fsub_undef_undef:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = fsub double undef, undef
+  %r = fsub fast double undef, undef
   ret double %r
 }
 
 define double @fmul_undef_undef(double %x) {
-; STRICT-LABEL: fmul_undef_undef:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulsd %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_undef:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul double undef, undef
+; ANY-LABEL: fmul_undef_undef:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast double undef, undef
   ret double %r
 }
 
@@ -275,7 +217,7 @@
 ; ANY-LABEL: fdiv_undef_undef:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = fdiv double undef, undef
+  %r = fdiv fast double undef, undef
   ret double %r
 }
 
@@ -283,7 +225,7 @@
 ; ANY-LABEL: frem_undef_undef:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = frem double undef, undef
+  %r = frem fast double undef, undef
   ret double %r
 }
 
@@ -303,15 +245,10 @@
 }
 
 define float @fadd_undef_op1_constant(float %x) {
-; STRICT-LABEL: fadd_undef_op1_constant:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addss {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op1_constant:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd float 2.0, undef
+; ANY-LABEL: fadd_undef_op1_constant:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast float 2.0, undef
   ret float %r
 }
 
@@ -324,16 +261,10 @@
 }
 
 define float @fsub_undef_op1_constant(float %x) {
-; STRICT-LABEL: fsub_undef_op1_constant:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; STRICT-NEXT:    subss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fsub_undef_op1_constant:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fsub float 4.0, undef
+; ANY-LABEL: fsub_undef_op1_constant:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fsub fast float 4.0, undef
   ret float %r
 }
 
@@ -351,15 +282,10 @@
 }
 
 define float @fmul_undef_op1_constant(float %x) {
-; STRICT-LABEL: fmul_undef_op1_constant:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulss {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op1_constant:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul float 6.0, undef
+; ANY-LABEL: fmul_undef_op1_constant:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast float 6.0, undef
   ret float %r
 }
 
@@ -372,16 +298,10 @@
 }
 
 define float @fdiv_undef_op1_constant(float %x) {
-; STRICT-LABEL: fdiv_undef_op1_constant:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; STRICT-NEXT:    divss %xmm0, %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fdiv_undef_op1_constant:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fdiv float 8.0, undef
+; ANY-LABEL: fdiv_undef_op1_constant:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fdiv fast float 8.0, undef
   ret float %r
 }
 
@@ -394,42 +314,27 @@
 }
 
 define float @frem_undef_op1_constant(float %x) {
-; STRICT-LABEL: frem_undef_op1_constant:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; STRICT-NEXT:    jmp fmodf # TAILCALL
-;
-; UNSAFE-LABEL: frem_undef_op1_constant:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = frem float 10.0, undef
+; ANY-LABEL: frem_undef_op1_constant:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = frem fast float 10.0, undef
   ret float %r
 }
 
 ; Constant folding - special constants: NaN.
 
 define double @fadd_undef_op0_constant_nan(double %x) {
-; STRICT-LABEL: fadd_undef_op0_constant_nan:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op0_constant_nan:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd double undef, 0x7FF8000000000000
+; ANY-LABEL: fadd_undef_op0_constant_nan:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast double undef, 0x7FF8000000000000
   ret double %r
 }
 
 define double @fadd_undef_op1_fast_constant_nan(double %x) {
-; STRICT-LABEL: fadd_undef_op1_fast_constant_nan:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op1_fast_constant_nan:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fadd_undef_op1_fast_constant_nan:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fadd fast double 0xFFF0000000000001, undef
   ret double %r
 }
@@ -457,27 +362,17 @@
 }
 
 define double @fmul_undef_op0_constant_nan(double %x) {
-; STRICT-LABEL: fmul_undef_op0_constant_nan:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op0_constant_nan:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul double undef, 0x7FF8000000000100
+; ANY-LABEL: fmul_undef_op0_constant_nan:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast double undef, 0x7FF8000000000100
   ret double %r
 }
 
 define double @fmul_undef_op1_fast_constant_nan(double %x) {
-; STRICT-LABEL: fmul_undef_op1_fast_constant_nan:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op1_fast_constant_nan:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fmul_undef_op1_fast_constant_nan:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fmul fast double 0xFFF0000000000101, undef
   ret double %r
 }
@@ -508,19 +403,14 @@
 ; ANY-LABEL: frem_undef_op0_constant_nan:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = frem double undef, 0x7FF8000000001000
+  %r = frem fast double undef, 0x7FF8000000001000
   ret double %r
 }
 
 define double @frem_undef_op1_fast_constant_nan(double %x) {
-; STRICT-LABEL: frem_undef_op1_fast_constant_nan:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    movsd {{.*#+}} xmm0 = mem[0],zero
-; STRICT-NEXT:    jmp fmod # TAILCALL
-;
-; UNSAFE-LABEL: frem_undef_op1_fast_constant_nan:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: frem_undef_op1_fast_constant_nan:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = frem fast double 0xFFF0000000001001, undef
   ret double %r
 }
@@ -528,27 +418,17 @@
 ; Constant folding - special constants: Inf.
 
 define double @fadd_undef_op0_constant_inf(double %x) {
-; STRICT-LABEL: fadd_undef_op0_constant_inf:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op0_constant_inf:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fadd double undef, 0x7FF0000000000000
+; ANY-LABEL: fadd_undef_op0_constant_inf:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fadd fast double undef, 0x7FF0000000000000
   ret double %r
 }
 
 define double @fadd_undef_op1_fast_constant_inf(double %x) {
-; STRICT-LABEL: fadd_undef_op1_fast_constant_inf:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    addsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fadd_undef_op1_fast_constant_inf:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fadd_undef_op1_fast_constant_inf:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fadd fast double 0xFFF0000000000000, undef
   ret double %r
 }
@@ -557,7 +437,7 @@
 ; ANY-LABEL: fsub_undef_op0_constant_inf:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = fsub double undef, 0xFFF0000000000000
+  %r = fsub fast double undef, 0xFFF0000000000000
   ret double %r
 }
 
@@ -576,27 +456,17 @@
 }
 
 define double @fmul_undef_op0_constant_inf(double %x) {
-; STRICT-LABEL: fmul_undef_op0_constant_inf:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op0_constant_inf:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
-  %r = fmul double undef, 0x7FF0000000000000
+; ANY-LABEL: fmul_undef_op0_constant_inf:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
+  %r = fmul fast double undef, 0x7FF0000000000000
   ret double %r
 }
 
 define double @fmul_undef_op1_fast_constant_inf(double %x) {
-; STRICT-LABEL: fmul_undef_op1_fast_constant_inf:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    mulsd {{.*}}(%rip), %xmm0
-; STRICT-NEXT:    retq
-;
-; UNSAFE-LABEL: fmul_undef_op1_fast_constant_inf:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: fmul_undef_op1_fast_constant_inf:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = fmul fast double 0xFFF0000000000000, undef
   ret double %r
 }
@@ -627,19 +497,14 @@
 ; ANY-LABEL: frem_undef_op0_constant_inf:
 ; ANY:       # %bb.0:
 ; ANY-NEXT:    retq
-  %r = frem double undef, 0x7FF0000000000000
+  %r = frem fast double undef, 0x7FF0000000000000
   ret double %r
 }
 
 define double @frem_undef_op1_fast_constant_inf(double %x) {
-; STRICT-LABEL: frem_undef_op1_fast_constant_inf:
-; STRICT:       # %bb.0:
-; STRICT-NEXT:    movsd {{.*#+}} xmm0 = mem[0],zero
-; STRICT-NEXT:    jmp fmod # TAILCALL
-;
-; UNSAFE-LABEL: frem_undef_op1_fast_constant_inf:
-; UNSAFE:       # %bb.0:
-; UNSAFE-NEXT:    retq
+; ANY-LABEL: frem_undef_op1_fast_constant_inf:
+; ANY:       # %bb.0:
+; ANY-NEXT:    retq
   %r = frem fast double 0xFFF0000000000000, undef
   ret double %r
 }