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

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index b1c16f2357891f567363bd287f8d2da95b9f7e9e..f9fd8d6a4017838c90e5b00f795a25d44edc3be5 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -204,15 +204,15 @@ void MacroAssembler::RememberedSetHelper(
   mov(Operand::StaticVariable(store_buffer), scratch);
   // Call stub on end of buffer.
   // Check for end of buffer.
-  test(scratch, Immediate(StoreBuffer::kStoreBufferOverflowBit));
+  test(scratch, Immediate(StoreBuffer::kStoreBufferMask));
   if (and_then == kReturnAtEnd) {
     Label buffer_overflowed;
-    j(not_equal, &buffer_overflowed, Label::kNear);
+    j(equal, &buffer_overflowed, Label::kNear);
     ret(0);
     bind(&buffer_overflowed);
   } else {
     DCHECK(and_then == kFallThroughAtEnd);
-    j(equal, &done, Label::kNear);
+    j(not_equal, &done, Label::kNear);
   }
   StoreBufferOverflowStub store_buffer_overflow(isolate(), save_fp);
   CallStub(&store_buffer_overflow);