Change store buffer overflow check to not rely on the store buffer being (2*Size) aligned.

src/mips64/macro-assembler-mips64.cc

 // Copyright 2012 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 <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_MIPS64
 
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
@@ skipping 467 matching lines @@
       ExternalReference::store_buffer_top(isolate());
   li(t8, Operand(store_buffer));
   ld(scratch, MemOperand(t8));
   // Store pointer to buffer and increment buffer top.
   sd(address, MemOperand(scratch));
   Daddu(scratch, scratch, kPointerSize);
   // Write back new top of buffer.
   sd(scratch, MemOperand(t8));
   // Call stub on end of buffer.
   // Check for end of buffer.
-  And(t8, scratch, Operand(StoreBuffer::kStoreBufferOverflowBit));
+  And(t8, scratch, Operand(StoreBuffer::kStoreBufferMask));
   DCHECK(!scratch.is(t8));
   if (and_then == kFallThroughAtEnd) {
-    Branch(&done, eq, t8, Operand(zero_reg));
+    Branch(&done, ne, t8, Operand(zero_reg));
   } else {
     DCHECK(and_then == kReturnAtEnd);
-    Ret(eq, t8, Operand(zero_reg));
+    Ret(ne, t8, Operand(zero_reg));
   }
   push(ra);
   StoreBufferOverflowStub store_buffer_overflow(isolate(), fp_mode);
   CallStub(&store_buffer_overflow);
   pop(ra);
   bind(&done);
   if (and_then == kReturnAtEnd) {
     Ret();
   }
 }
@@ skipping 6374 matching lines @@
   if (mag.shift > 0) sra(result, result, mag.shift);
   srl(at, dividend, 31);
   Addu(result, result, Operand(at));
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64