diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -519,13 +519,6 @@
   unsigned NextTmpIdx = 0;
   FAddend TmpResult[3];
 
-  // Points to the constant addend of the resulting simplified expression.
-  // If the resulting expr has constant-addend, this constant-addend is
-  // desirable to reside at the top of the resulting expression tree. Placing
-  // constant close to supper-expr(s) will potentially reveal some optimization
-  // opportunities in super-expr(s).
-  const FAddend *ConstAdd = nullptr;
-
   // Simplified addends are placed <SimpVect>.
   AddendVect SimpVect;
 
@@ -541,6 +534,14 @@
     }
 
     Value *Val = ThisAddend->getSymVal();
+
+    // If the resulting expr has constant-addend, this constant-addend is
+    // desirable to reside at the top of the resulting expression tree. Placing
+    // constant close to super-expr(s) will potentially reveal some
+    // optimization opportunities in super-expr(s). Here we do not implement
+    // this logic intentionally and rely on SimplifyAssociativeOrCommutative
+    // call later.
+
     unsigned StartIdx = SimpVect.size();
     SimpVect.push_back(ThisAddend);
 
@@ -569,14 +570,8 @@
 
       // Pop all addends being folded and push the resulting folded addend.
       SimpVect.resize(StartIdx);
-      if (Val) {
-        if (!R.isZero()) {
-          SimpVect.push_back(&R);
-        }
-      } else {
-        // Don't push constant addend at this time. It will be the last element
-        // of <SimpVect>.
-        ConstAdd = &R;
+      if (!R.isZero()) {
+        SimpVect.push_back(&R);
       }
     }
   }
@@ -584,9 +579,6 @@
   assert((NextTmpIdx <= array_lengthof(TmpResult) + 1) &&
          "out-of-bound access");
 
-  if (ConstAdd)
-    SimpVect.push_back(ConstAdd);
-
   Value *Result;
   if (!SimpVect.empty())
     Result = createNaryFAdd(SimpVect, InstrQuota);
diff --git a/llvm/test/Transforms/Reassociate/fast-basictest.ll b/llvm/test/Transforms/Reassociate/fast-basictest.ll
--- a/llvm/test/Transforms/Reassociate/fast-basictest.ll
+++ b/llvm/test/Transforms/Reassociate/fast-basictest.ll
@@ -353,8 +353,8 @@
 ; Check again with 'reassoc' and 'nsz' ('nsz' not technically required).
 define float @test12_reassoc_nsz(float %X) {
 ; CHECK-LABEL: @test12_reassoc_nsz(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul reassoc nsz float [[X:%.*]], 3.000000e+00
-; CHECK-NEXT:    [[TMP2:%.*]] = fsub reassoc nsz float 6.000000e+00, [[TMP1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = fmul reassoc nsz float [[X:%.*]], -3.000000e+00
+; CHECK-NEXT:    [[TMP2:%.*]] = fadd reassoc nsz float [[TMP1]], 6.000000e+00
 ; CHECK-NEXT:    ret float [[TMP2]]
 ;
   %A = fsub reassoc nsz float 1.000000e+00, %X