Prevent deopt when assigning double values to typed arrays

src/arm/lithium-arm.cc

 // Copyright 2011 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 840 matching lines @@
   if (right_value->IsConstant()) {
     HConstant* constant = HConstant::cast(right_value);
     right = chunk_->DefineConstantOperand(constant);
     constant_value = constant->Integer32Value() & 0x1f;
   } else {
     right = UseRegister(right_value);
   }
 
   // Shift operations can only deoptimize if we do a logical shift
   // by 0 and the result cannot be truncated to int32.
-  bool can_deopt = (op == Token::SHR && constant_value == 0);
-  if (can_deopt) {
-    bool can_truncate = true;
-    for (int i = 0; i < instr->uses()->length(); i++) {
-      if (!instr->uses()->at(i)->CheckFlag(HValue::kTruncatingToInt32)) {
-        can_truncate = false;
-        break;
-      }
-    }
-    can_deopt = !can_truncate;
-  }
+  bool can_deopt = op == Token::SHR &&
+      constant_value == 0 &&
+      !instr->representation().Equals(Representation::TruncatedInteger32());
 
   LInstruction* result =
       DefineSameAsFirst(new LShiftI(op, left, right, can_deopt));
   if (can_deopt) AssignEnvironment(result);
   return result;
 }
 
 
 LInstruction* LChunkBuilder::DoArithmeticD(Token::Value op,
                                            HArithmeticBinaryOperation* instr) {
@@ skipping 1250 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLeaveInlined(HLeaveInlined* instr) {
   HEnvironment* outer = current_block_->last_environment()->outer();
   current_block_->UpdateEnvironment(outer);
   return NULL;
 }
 
 
 } }  // namespace v8::internal