Merge r10380, r10381 from the bleeding_edge to the 3.7 branch.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
===================================================================
--- src/x64/code-stubs-x64.cc	(revision 10356)
+++ src/x64/code-stubs-x64.cc	(working copy)
@@ -4049,12 +4049,14 @@
     // Get return address and delta to inlined map check.
     __ movq(kScratchRegister, Operand(rsp, 0 * kPointerSize));
     __ subq(kScratchRegister, Operand(rsp, 1 * kPointerSize));
-    __ movq(Operand(kScratchRegister, kOffsetToMapCheckValue), rax);
     if (FLAG_debug_code) {
       __ movl(rdi, Immediate(kWordBeforeMapCheckValue));
       __ cmpl(Operand(kScratchRegister, kOffsetToMapCheckValue - 4), rdi);
       __ Assert(equal, "InstanceofStub unexpected call site cache (check).");
     }
+    __ movq(kScratchRegister,
+            Operand(kScratchRegister, kOffsetToMapCheckValue));
+    __ movq(Operand(kScratchRegister, 0), rax);
   }
 
   __ movq(rcx, FieldOperand(rax, Map::kPrototypeOffset));