Fix bug in r6930 and r6933

The loading the register used for the null object was to early and it could be clobbered.

TBR=karlklose@chromium.org
BUG=none
TEST=mozilla/ecma_3/Statements/regress-131348
Review URL: http://codereview.chromium.org/6578020

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6937 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/full-codegen-arm.cc

@@ -880,10 +880,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   ForIn loop_statement(this, stmt);
   increment_loop_depth();
 
-  // Load null value as it is used several times below.
-  Register null_value = r5;
-  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
-
   // Get the object to enumerate over. Both SpiderMonkey and JSC
   // ignore null and undefined in contrast to the specification; see
   // ECMA-262 section 12.6.4.
@@ -891,6 +887,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ cmp(r0, ip);
   __ b(eq, &exit);
+  Register null_value = r5;
+  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
   __ cmp(r0, null_value);
   __ b(eq, &exit);
 

src/x64/full-codegen-x64.cc

@@ -854,16 +854,14 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   ForIn loop_statement(this, stmt);
   increment_loop_depth();
 
-  // Load null value as it is used several times below.
-  Register null_value = rdi;
-  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
-
   // Get the object to enumerate over. Both SpiderMonkey and JSC
   // ignore null and undefined in contrast to the specification; see
   // ECMA-262 section 12.6.4.
   VisitForAccumulatorValue(stmt->enumerable());
   __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
   __ j(equal, &exit);
+  Register null_value = rdi;
+  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
   __ cmpq(rax, null_value);
   __ j(equal, &exit);