Allow uint32 value on optimized frames if they are consumed by safe operations.

src/arm/lithium-arm.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 695 matching lines @@
   LOperand* right = NULL;
   int constant_value = 0;
   if (right_value->IsConstant()) {
     HConstant* constant = HConstant::cast(right_value);
     right = chunk_->DefineConstantOperand(constant);
     constant_value = constant->Integer32Value() & 0x1f;
   } else {
     right = UseRegisterAtStart(right_value);
   }
 
-  // Shift operations can only deoptimize if we do a logical shift
-  // by 0 and the result cannot be truncated to int32.
-  bool may_deopt = (op == Token::SHR && constant_value == 0);
   bool does_deopt = false;
-  if (may_deopt) {
-    for (HUseIterator it(instr->uses()); !it.Done(); it.Advance()) {
-      if (!it.value()->CheckFlag(HValue::kTruncatingToInt32)) {
-        does_deopt = true;
-        break;
+
+  if (FLAG_opt_safe_uint32_operations) {
+    does_deopt = !instr->CheckFlag(HInstruction::kUint32);
+  } else {
+    // Shift operations can only deoptimize if we do a logical shift
+    // by 0 and the result cannot be truncated to int32.
+    bool may_deopt = (op == Token::SHR && constant_value == 0);
+    if (may_deopt) {
+      for (HUseIterator it(instr->uses()); !it.Done(); it.Advance()) {
+        if (!it.value()->CheckFlag(HValue::kTruncatingToInt32)) {
+          does_deopt = true;
+          break;
+        }
       }
     }
   }
 
   LInstruction* result =
       DefineAsRegister(new(zone()) LShiftI(op, left, right, does_deopt));
   return does_deopt ? AssignEnvironment(result) : result;
 }
 
 
@@ skipping 138 matching lines @@
 
     HValue* value = hydrogen_env->values()->at(i);
     LOperand* op = NULL;
     if (value->IsArgumentsObject()) {
       op = NULL;
     } else if (value->IsPushArgument()) {
       op = new(zone()) LArgument(argument_index++);
     } else {
       op = UseAny(value);
     }
-    result->AddValue(op, value->representation());
+    result->AddValue(op,
+                     value->representation(),
+                     value->CheckFlag(HInstruction::kUint32));
   }
 
   if (hydrogen_env->frame_type() == JS_FUNCTION) {
     *argument_index_accumulator = argument_index;
   }
 
   return result;
 }
 
 
@@ skipping 748 matching lines @@
       LOperand* value = UseRegister(instr->value());
       LOperand* temp1 = TempRegister();
       LOperand* temp2 = instr->CanTruncateToInt32() ? TempRegister() : NULL;
       LDoubleToI* res = new(zone()) LDoubleToI(value, temp1, temp2);
       return AssignEnvironment(DefineAsRegister(res));
     }
   } else if (from.IsInteger32()) {
     if (to.IsTagged()) {
       HValue* val = instr->value();
       LOperand* value = UseRegisterAtStart(val);
-      if (val->HasRange() && val->range()->IsInSmiRange()) {
+      if (val->CheckFlag(HInstruction::kUint32)) {
+        LNumberTagU* result = new(zone()) LNumberTagU(value);
+        return AssignEnvironment(AssignPointerMap(DefineSameAsFirst(result)));
+      } else if (val->HasRange() && val->range()->IsInSmiRange()) {
         return DefineAsRegister(new(zone()) LSmiTag(value));
       } else {
         LNumberTagI* result = new(zone()) LNumberTagI(value);
         return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
       }
     } else {
       ASSERT(to.IsDouble());
-      LOperand* value = Use(instr->value());
-      return DefineAsRegister(new(zone()) LInteger32ToDouble(value));
+      if (instr->value()->CheckFlag(HInstruction::kUint32)) {
+        return DefineAsRegister(
+            new(zone()) LUint32ToDouble(UseRegister(instr->value())));
+      } else {
+        return DefineAsRegister(
+            new(zone()) LInteger32ToDouble(Use(instr->value())));
+      }
     }
   }
   UNREACHABLE();
   return NULL;
 }
 
 
 LInstruction* LChunkBuilder::DoCheckNonSmi(HCheckNonSmi* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   return AssignEnvironment(new(zone()) LCheckNonSmi(value));
@@ skipping 627 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal