Addresses some performance regression in the GenericBinaryOpStub on ARM followin...

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
===================================================================
--- src/arm/code-stubs-arm.cc	(revision 6012)
+++ src/arm/code-stubs-arm.cc	(working copy)
@@ -1229,12 +1229,14 @@
   bool generate_code_to_calculate_answer = true;
 
   if (ShouldGenerateFPCode()) {
-    if (runtime_operands_type_ == BinaryOpIC::DEFAULT) {
+    // DIV has neither SmiSmi fast code nor specialized slow code.
+    // So don't try to patch a DIV Stub.
+    if ((runtime_operands_type_ == BinaryOpIC::DEFAULT) &&
+        (op_ != Token::DIV)) {
       switch (op_) {
         case Token::ADD:
         case Token::SUB:
         case Token::MUL:
-        case Token::DIV:
           GenerateTypeTransition(masm);  // Tail call.
           generate_code_to_calculate_answer = false;
           break;
@@ -1299,7 +1301,8 @@
       // HEAP_NUMBERS stub is slower than GENERIC on a pair of smis.
       // r0 is known to be a smi. If r1 is also a smi then switch to GENERIC.
       Label r1_is_not_smi;
-      if (runtime_operands_type_ == BinaryOpIC::HEAP_NUMBERS) {
+      if ((runtime_operands_type_ == BinaryOpIC::HEAP_NUMBERS) &&
+          HasSmiSmiFastPath()) {
         __ tst(r1, Operand(kSmiTagMask));
         __ b(ne, &r1_is_not_smi);
         GenerateTypeTransition(masm);  // Tail call.