Fix approximation of CanDeoptimize() and other small store elimination fixes.

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 845 matching lines @@
     case HValue::kArgumentsLength:
     case HValue::kArgumentsObject:
     case HValue::kBoundsCheckBaseIndexInformation:
     case HValue::kCapturedObject:
     case HValue::kClampToUint8:
     case HValue::kConstant:
     case HValue::kContext:
     case HValue::kDateField:
     case HValue::kDebugBreak:
     case HValue::kDeclareGlobals:
-    case HValue::kDiv:
     case HValue::kDummyUse:
     case HValue::kEnterInlined:
     case HValue::kEnvironmentMarker:
     case HValue::kForInCacheArray:
     case HValue::kForInPrepareMap:
     case HValue::kFunctionLiteral:
     case HValue::kGetCachedArrayIndex:
     case HValue::kGoto:
     case HValue::kInnerAllocatedObject:
     case HValue::kInstanceOf:
     case HValue::kInstanceOfKnownGlobal:
     case HValue::kInvokeFunction:
     case HValue::kLeaveInlined:
     case HValue::kLoadContextSlot:
     case HValue::kLoadFieldByIndex:
     case HValue::kLoadFunctionPrototype:
     case HValue::kLoadGlobalCell:
     case HValue::kLoadGlobalGeneric:
     case HValue::kLoadKeyed:
     case HValue::kLoadKeyedGeneric:
     case HValue::kLoadNamedField:
     case HValue::kLoadNamedGeneric:
     case HValue::kLoadRoot:
     case HValue::kMapEnumLength:
     case HValue::kMathFloorOfDiv:
     case HValue::kMathMinMax:
-    case HValue::kMod:
     case HValue::kMul:
     case HValue::kOsrEntry:
     case HValue::kParameter:
     case HValue::kPower:
     case HValue::kPushArgument:
     case HValue::kRor:
     case HValue::kSar:
     case HValue::kSeqStringGetChar:
     case HValue::kSeqStringSetChar:
     case HValue::kShl:
@@ skipping 26 matching lines @@
     case HValue::kChange:
     case HValue::kCompareGeneric:
       // These instructions might deoptimize if they are not primitive.
       if (!HasPrimitiveRepresentation(this)) return true;
       for (int i = 0; i < OperandCount(); i++) {
         HValue* input = OperandAt(i);
         if (!HasPrimitiveRepresentation(input)) return true;
       }
       return false;
     default:
+      // TODO(titzer): kDiv and kMod can deoptimize under some circumstances.
       return true;
   }
 }
 
 
 void HDummyUse::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
 }
 
 
@@ skipping 3744 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal