Index: lib/Transforms/InstCombine/InstCombineAddSub.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -511,7 +511,7 @@
 }
 
 Value *FAddCombine::simplify(Instruction *I) {
-  assert(I->isFast() && "Expected 'fast' instruction");
+  assert(I->hasAllowReassoc() && "Expected 'reassoc' instruction");
 
   // Currently we are not able to handle vector type.
   if (I->getType()->isVectorTy())
@@ -1378,7 +1378,7 @@
   if (Value *V = SimplifySelectsFeedingBinaryOp(I, LHS, RHS))
     return replaceInstUsesWith(I, V);
 
-  if (I.isFast()) {
+  if (I.hasAllowReassoc()) {
     if (Value *V = FAddCombine(Builder).simplify(&I))
       return replaceInstUsesWith(I, V);
   }
@@ -1747,7 +1747,7 @@
   if (Value *V = SimplifySelectsFeedingBinaryOp(I, Op0, Op1))
     return replaceInstUsesWith(I, V);
 
-  if (I.isFast()) {
+  if (I.hasAllowReassoc()) {
     if (Value *V = FAddCombine(Builder).simplify(&I))
       return replaceInstUsesWith(I, V);
   }
Index: test/Transforms/Reassociate/fast-MissedTree.ll
===================================================================
--- test/Transforms/Reassociate/fast-MissedTree.ll
+++ test/Transforms/Reassociate/fast-MissedTree.ll
@@ -15,9 +15,7 @@
 
 define float @test1_reassoc(float %A, float %B) {
 ; CHECK-LABEL: @test1_reassoc(
-; CHECK-NEXT:    [[W:%.*]] = fadd reassoc float %B, -5.000000e+00
-; CHECK-NEXT:    [[Y:%.*]] = fadd reassoc float %A, 5.000000e+00
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[Y]], [[W]]
+; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float %A, %B
 ; CHECK-NEXT:    ret float [[Z]]
 ;
   %W = fadd reassoc float %B, -5.0
Index: test/Transforms/Reassociate/fast-SubReassociate.ll
===================================================================
--- test/Transforms/Reassociate/fast-SubReassociate.ll
+++ test/Transforms/Reassociate/fast-SubReassociate.ll
@@ -32,10 +32,7 @@
 
 define float @test2_reassoc(float %A, float %B) {
 ; CHECK-LABEL: @test2_reassoc(
-; CHECK-NEXT:    [[W:%.*]] = fadd reassoc float %B, 5.000000e+00
-; CHECK-NEXT:    [[X:%.*]] = fadd reassoc float %A, -7.000000e+00
-; CHECK-NEXT:    [[Y:%.*]] = fsub reassoc float [[X]], [[W]]
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[Y]], 1.200000e+01
+; CHECK-NEXT:    [[Z:%.*]] = fsub reassoc float %A, %B
 ; CHECK-NEXT:    ret float [[Z]]
 ;
   %W = fadd reassoc float %B, 5.000000e+00
Index: test/Transforms/Reassociate/fast-basictest.ll
===================================================================
--- test/Transforms/Reassociate/fast-basictest.ll
+++ test/Transforms/Reassociate/fast-basictest.ll
@@ -14,9 +14,8 @@
 
 define float @test1_reassoc(float %arg) {
 ; CHECK-LABEL: @test1_reassoc(
-; CHECK-NEXT:    [[T1:%.*]] = fsub reassoc float -1.200000e+01, [[ARG:%.*]]
-; CHECK-NEXT:    [[T2:%.*]] = fadd reassoc float [[T1]], 1.200000e+01
-; CHECK-NEXT:    ret float [[T2]]
+; CHECK-NEXT:    [[ARG_NEG:%.*]] = fsub reassoc float 0.000000e+00, [[ARG:%.*]]
+; CHECK-NEXT:    ret float [[ARG_NEG]]
 ;
   %t1 = fsub reassoc float -1.200000e+01, %arg
   %t2 = fadd reassoc float %t1, 1.200000e+01
@@ -212,9 +211,8 @@
 
 define float @test9_reassoc(float %X) {
 ; CHECK-LABEL: @test9_reassoc(
-; CHECK-NEXT:    [[Y:%.*]] = fmul reassoc float [[X:%.*]], 4.700000e+01
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[Y]], [[Y]]
-; CHECK-NEXT:    ret float [[Z]]
+; CHECK-NEXT:    [[FACTOR:%.*]] = fmul reassoc float [[X:%.*]], 9.400000e+01
+; CHECK-NEXT:    ret float [[FACTOR]]
 ;
   %Y = fmul reassoc float %X, 4.700000e+01
   %Z = fadd reassoc float %Y, %Y
@@ -233,9 +231,8 @@
 
 define float @test10_reassoc(float %X) {
 ; CHECK-LABEL: @test10_reassoc(
-; CHECK-NEXT:    [[Y:%.*]] = fadd reassoc float [[X:%.*]], [[X]]
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[Y]], [[X]]
-; CHECK-NEXT:    ret float [[Z]]
+; CHECK-NEXT:    [[FACTOR:%.*]] = fmul reassoc float [[X:%.*]], 3.000000e+00
+; CHECK-NEXT:    ret float [[FACTOR]]
 ;
   %Y = fadd reassoc float %X ,%X
   %Z = fadd reassoc float %Y, %X
@@ -255,10 +252,8 @@
 
 define float @test11_reassoc(float %W) {
 ; CHECK-LABEL: @test11_reassoc(
-; CHECK-NEXT:    [[X:%.*]] = fmul reassoc float [[W:%.*]], 1.270000e+02
-; CHECK-NEXT:    [[Y:%.*]] = fadd reassoc float [[X]], [[X]]
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[X]], [[Y]]
-; CHECK-NEXT:    ret float [[Z]]
+; CHECK-NEXT:    [[FACTOR:%.*]] = fmul reassoc float [[W:%.*]], 3.810000e+02
+; CHECK-NEXT:    ret float [[FACTOR]]
 ;
   %X = fmul reassoc float %W, 127.0
   %Y = fadd reassoc float %X ,%X
@@ -282,11 +277,8 @@
 
 define float @test12_reassoc(float %X) {
 ; CHECK-LABEL: @test12_reassoc(
-; CHECK-NEXT:    [[A:%.*]] = fsub reassoc float 1.000000e+00, [[X:%.*]]
-; CHECK-NEXT:    [[B:%.*]] = fsub reassoc float 2.000000e+00, [[X]]
-; CHECK-NEXT:    [[C:%.*]] = fsub reassoc float 3.000000e+00, [[X]]
-; CHECK-NEXT:    [[Y:%.*]] = fadd reassoc float [[A]], [[B]]
-; CHECK-NEXT:    [[Z:%.*]] = fadd reassoc float [[C]], [[Y]]
+; CHECK-NEXT:    [[FACTOR:%.*]] = fmul reassoc float [[X:%.*]], 3.000000e+00
+; CHECK-NEXT:    [[Z:%.*]] = fsub reassoc float 6.000000e+00, [[FACTOR]]
 ; CHECK-NEXT:    ret float [[Z]]
 ;
   %A = fsub reassoc float 1.000000e+00, %X
@@ -339,10 +331,9 @@
 
 define float @test14_reassoc(float %X1, float %X2) {
 ; CHECK-LABEL: @test14_reassoc(
-; CHECK-NEXT:    [[B:%.*]] = fmul reassoc float [[X1:%.*]], 4.700000e+01
-; CHECK-NEXT:    [[C:%.*]] = fmul reassoc float [[X2:%.*]], 4.700000e+01
-; CHECK-NEXT:    [[D1:%.*]] = fsub reassoc float [[B]], [[C]]
-; CHECK-NEXT:    ret float [[D1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = fsub reassoc float [[X1:%.*]], [[X2:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = fmul reassoc float [[TMP1]], 4.700000e+01
+; CHECK-NEXT:    ret float [[TMP2]]
 ;
   %B = fmul reassoc float %X1, 47.   ; X1*47
   %C = fmul reassoc float %X2, -47.  ; X2*-47
@@ -385,11 +376,8 @@
 
 define float @test16_reassoc(float %b, float %a) {
 ; CHECK-LABEL: @test16_reassoc(
-; CHECK-NEXT:    [[TMP1:%.*]] = fadd reassoc float [[A:%.*]], 1.234000e+03
-; CHECK-NEXT:    [[TMP2:%.*]] = fadd reassoc float [[TMP1]], [[B:%.*]]
-; CHECK-NEXT:    [[TMP3:%.*]] = fsub reassoc float 0.000000e+00, [[A]]
-; CHECK-NEXT:    [[TMP4:%.*]] = fadd reassoc float [[TMP3]], [[TMP2]]
-; CHECK-NEXT:    ret float [[TMP4]]
+; CHECK-NEXT:    [[TMP1:%.*]] = fadd reassoc float [[B:%.*]], 1.234000e+03
+; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %1 = fadd reassoc float %a, 1234.0
   %2 = fadd reassoc float %b, %1