Do not emit debug check in optimized IC stubs

runtime/vm/stub_code_mips.cc

Index: runtime/vm/stub_code_mips.cc
diff --git a/runtime/vm/stub_code_mips.cc b/runtime/vm/stub_code_mips.cc
index 8019cd81b36548c1ec0fa93345a4c3b3004421c8..9210b458e650035bfe93d9c23159b701ff1495b9 100644
--- a/runtime/vm/stub_code_mips.cc
+++ b/runtime/vm/stub_code_mips.cc
@@ -1443,7 +1443,8 @@ void StubCode::GenerateNArgsCheckInlineCacheStub(
     intptr_t num_args,
     const RuntimeEntry& handle_ic_miss,
     Token::Kind kind,
-    RangeCollectionMode range_collection_mode) {
+    RangeCollectionMode range_collection_mode,
+    bool optimized) {
   __ Comment("NArgsCheckInlineCacheStub");
   ASSERT(num_args > 0);
 #if defined(DEBUG)
@@ -1461,7 +1462,7 @@ void StubCode::GenerateNArgsCheckInlineCacheStub(
 
 
   Label stepping, done_stepping;
-  if (FLAG_support_debugger) {
+  if (FLAG_support_debugger && !optimized) {
     __ Comment("Check single stepping");
     __ LoadIsolate(T0);
     __ lbu(T0, Address(T0, Isolate::single_step_offset()));
@@ -1651,7 +1652,7 @@ void StubCode::GenerateNArgsCheckInlineCacheStub(
   }
 
   // Call single step callback in debugger.
-  if (FLAG_support_debugger) {
+  if (FLAG_support_debugger && !optimized) {
     __ Bind(&stepping);
     __ EnterStubFrame();
     __ addiu(SP, SP, Immediate(-2 * kWordSize));
@@ -1742,7 +1743,7 @@ void StubCode::GenerateOneArgOptimizedCheckInlineCacheStub(
   GenerateOptimizedUsageCounterIncrement(assembler);
   GenerateNArgsCheckInlineCacheStub(assembler, 1,
       kInlineCacheMissHandlerOneArgRuntimeEntry, Token::kILLEGAL,
-      kIgnoreRanges);
+      kIgnoreRanges, true /* optimized */);
 }
 
 
@@ -1751,7 +1752,7 @@ void StubCode::GenerateTwoArgsOptimizedCheckInlineCacheStub(
   GenerateOptimizedUsageCounterIncrement(assembler);
   GenerateNArgsCheckInlineCacheStub(assembler, 2,
       kInlineCacheMissHandlerTwoArgsRuntimeEntry, Token::kILLEGAL,
-      kIgnoreRanges);
+      kIgnoreRanges, true /* optimized */);
 }