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

src/mips64/macro-assembler-mips64.cc

Index: src/mips64/macro-assembler-mips64.cc
diff --git a/src/mips64/macro-assembler-mips64.cc b/src/mips64/macro-assembler-mips64.cc
index 9e49c477300a206926fa1032a4af62a8f54e4632..fb83fe9b76872c1b7ace3fb33bc41896173536b0 100644
--- a/src/mips64/macro-assembler-mips64.cc
+++ b/src/mips64/macro-assembler-mips64.cc
@@ -485,13 +485,13 @@ void MacroAssembler::RememberedSetHelper(Register object,  // For debug tests.
   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);