Lithium: avoid registers for constants when possible.

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 534 matching lines @@
 }
 
 
 LOperand* LChunkBuilder::UseRegisterOrConstantAtStart(HValue* value) {
   return value->IsConstant()
       ? chunk_->DefineConstantOperand(HConstant::cast(value))
       : UseRegisterAtStart(value);
 }
 
 
+LOperand* LChunkBuilder::UseConstant(HValue* value) {
+  return chunk_->DefineConstantOperand(HConstant::cast(value));
+}
+
+
 LOperand* LChunkBuilder::UseAny(HValue* value) {
   return value->IsConstant()
       ? chunk_->DefineConstantOperand(HConstant::cast(value))
       :  Use(value, new(zone()) LUnallocated(LUnallocated::ANY));
 }
 
 
 LOperand* LChunkBuilder::Use(HValue* value, LUnallocated* operand) {
   if (value->EmitAtUses()) {
     HInstruction* instr = HInstruction::cast(value);
@@ skipping 1806 matching lines @@
 LInstruction* LChunkBuilder::DoAllocateObject(HAllocateObject* instr) {
   info()->MarkAsDeferredCalling();
   LAllocateObject* result =
       new(zone()) LAllocateObject(TempRegister(), TempRegister());
   return AssignPointerMap(DefineAsRegister(result));
 }
 
 
 LInstruction* LChunkBuilder::DoAllocate(HAllocate* instr) {
   info()->MarkAsDeferredCalling();
-  LOperand* size = UseTempRegister(instr->size());
+  LOperand* size = instr->size()->IsConstant()
+      ? UseConstant(instr->size())
+      : UseTempRegister(instr->size());
   LOperand* temp1 = TempRegister();
   LOperand* temp2 = TempRegister();
   LAllocate* result = new(zone()) LAllocate(size, temp1, temp2);
   return AssignPointerMap(DefineAsRegister(result));
 }
 
 
 LInstruction* LChunkBuilder::DoArrayLiteral(HArrayLiteral* instr) {
   return MarkAsCall(DefineFixed(new(zone()) LArrayLiteral, r0), instr);
 }
@@ skipping 222 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