Implement clearing of CompareICs.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc
index 0632ce439f3c2c91171dc70380e52b1893c9330d..6ba5fb6e2ce0ab10b01612f86a50dd5fa51e9843 100644
--- a/src/x64/ic-x64.cc
+++ b/src/x64/ic-x64.cc
@@ -1741,11 +1741,11 @@ void CompareIC::UpdateCaches(Handle<Object> x, Handle<Object> y) {
 
   // Activate inlined smi code.
   if (previous_state == UNINITIALIZED) {
-    PatchInlinedSmiCode(address());
+    PatchInlinedSmiCode(address(), ENABLE_INLINED_SMI_CHECK);
   }
 }
 
-void PatchInlinedSmiCode(Address address) {
+void PatchInlinedSmiCode(Address address, InlinedSmiCheck check) {
   // The address of the instruction following the call.
   Address test_instruction_address =
       address + Assembler::kCallTargetAddressOffset;
@@ -1766,14 +1766,18 @@ void PatchInlinedSmiCode(Address address) {
            address, test_instruction_address, delta);
   }
 
-  // Patch with a short conditional jump. There must be a
-  // short jump-if-carry/not-carry at this position.
+  // Patch with a short conditional jump. Enabling means switching from a short
+  // jump-if-carry/not-carry to jump-if-zero/not-zero, whereas disabling is the
+  // reverse operation of that.
   Address jmp_address = test_instruction_address - delta;
-  ASSERT(*jmp_address == Assembler::kJncShortOpcode ||
-         *jmp_address == Assembler::kJcShortOpcode);
-  Condition cc = *jmp_address == Assembler::kJncShortOpcode
-      ? not_zero
-      : zero;
+  ASSERT((check == ENABLE_INLINED_SMI_CHECK)
+         ? (*jmp_address == Assembler::kJncShortOpcode ||
+            *jmp_address == Assembler::kJcShortOpcode)
+         : (*jmp_address == Assembler::kJnzShortOpcode ||
+            *jmp_address == Assembler::kJzShortOpcode));
+  Condition cc = (check == ENABLE_INLINED_SMI_CHECK)
+      ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
+      : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }