[turbofan] Do not produce 2 ops for Int32AddWithOverflow.

src/compiler/ia32/instruction-selector-ia32.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
@@ skipping 1311 matching lines @@
   FlagsContinuation cont =
       FlagsContinuation::ForSet(kUnsignedLessThanOrEqual, node);
   VisitWordCompare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
   if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
     FlagsContinuation cont = FlagsContinuation::ForSet(kOverflow, ovf);
     return VisitBinop(this, node, kIA32Add, &cont);
+  } else {

[Benedikt Meurer, 2016/03/03 17:48:08]

This doesn't seem to be necessary, since there's a return above. Please keep
this version with the return for consistency with the rest of the file.

[Mircea Trofin, 2016/03/03 21:50:13]

Ugh... true. Haven't noticed the return.

+    FlagsContinuation cont;
+    VisitBinop(this, node, kIA32Add, &cont);
   }
-  FlagsContinuation cont;
-  VisitBinop(this, node, kIA32Add, &cont);
 }
 
 
 void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
   if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
     FlagsContinuation cont = FlagsContinuation::ForSet(kOverflow, ovf);
     return VisitBinop(this, node, kIA32Sub, &cont);
   }
   FlagsContinuation cont;
   VisitBinop(this, node, kIA32Sub, &cont);
@@ skipping 99 matching lines @@
              MachineOperatorBuilder::kFloat64RoundTruncate |
              MachineOperatorBuilder::kFloat32RoundTiesEven |
              MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8