Never call MacroAssembler::Allocate() with incorrect size.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5314 matching lines @@
     DCHECK(!instr->hydrogen()->IsOldDataSpaceAllocation());
     DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
     flags = static_cast<AllocationFlags>(flags | PRETENURE_OLD_POINTER_SPACE);
   } else if (instr->hydrogen()->IsOldDataSpaceAllocation()) {
     DCHECK(!instr->hydrogen()->IsNewSpaceAllocation());
     flags = static_cast<AllocationFlags>(flags | PRETENURE_OLD_DATA_SPACE);
   }
 
   if (instr->size()->IsConstantOperand()) {
     int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
-    if (size <= Page::kMaxRegularHeapObjectSize) {
+    if (static_cast<uint32_t>(size) <=
+        static_cast<uint32_t>(Page::kMaxRegularHeapObjectSize)) {
       __ Allocate(size, result, temp, no_reg, deferred->entry(), flags);
     } else {
       __ jmp(deferred->entry());
     }
   } else {
     Register size = ToRegister(instr->size());
     __ Allocate(size, result, temp, no_reg, deferred->entry(), flags);
   }
 
   __ bind(deferred->exit());
@@ skipping 534 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64