Add Uint32AddWithOverflow and Uint32SubWithOverflow machine operators.

src/compiler/instruction-selector-impl.h

 // 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.
 
 #ifndef V8_COMPILER_INSTRUCTION_SELECTOR_IMPL_H_
 #define V8_COMPILER_INSTRUCTION_SELECTOR_IMPL_H_
 
 #include "src/compiler/instruction.h"
 #include "src/compiler/instruction-selector.h"
 #include "src/compiler/linkage.h"
@@ skipping 252 matching lines @@
   void Negate() {
     DCHECK(!IsNone());
     condition_ = static_cast<FlagsCondition>(condition_ ^ 1);
   }
 
   void Commute() {
     DCHECK(!IsNone());
     switch (condition_) {
       case kEqual:
       case kNotEqual:
-      case kOverflow:
-      case kNotOverflow:
         return;
       case kSignedLessThan:
         condition_ = kSignedGreaterThan;
         return;
       case kSignedGreaterThanOrEqual:
         condition_ = kSignedLessThanOrEqual;
         return;
       case kSignedLessThanOrEqual:
         condition_ = kSignedGreaterThanOrEqual;
         return;
@@ skipping 20 matching lines @@
         return;
       case kUnorderedGreaterThanOrEqual:
         condition_ = kUnorderedLessThanOrEqual;
         return;
       case kUnorderedLessThanOrEqual:
         condition_ = kUnorderedGreaterThanOrEqual;
         return;
       case kUnorderedGreaterThan:
         condition_ = kUnorderedLessThan;
         return;
+      case kOverflow:
+      case kNotOverflow:
+        // We cannot commute these.
+        break;
     }
     UNREACHABLE();
   }
 
   void OverwriteAndNegateIfEqual(FlagsCondition condition) {
     bool negate = condition_ == kEqual;
     condition_ = condition;
     if (negate) Negate();
   }
 
@@ skipping 37 matching lines @@
   int control_count() { return descriptor->CanLazilyDeoptimize() ? 2 : 0; }
 
   int fixed_and_control_count() { return fixed_count + control_count(); }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_SELECTOR_IMPL_H_