Do not emit debug check in optimized IC stubs

runtime/vm/stub_code_arm.cc

Index: runtime/vm/stub_code_arm.cc
diff --git a/runtime/vm/stub_code_arm.cc b/runtime/vm/stub_code_arm.cc
index afe30f72a4e073ec76bb6b5409f4da1b60938478..08a6d0e556e632b14e56977868ea7abc101a27a6 100644
--- a/runtime/vm/stub_code_arm.cc
+++ b/runtime/vm/stub_code_arm.cc
@@ -1336,7 +1336,8 @@ 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) {
   ASSERT(num_args > 0);
 #if defined(DEBUG)
   { Label ok;
@@ -1353,7 +1354,7 @@ void StubCode::GenerateNArgsCheckInlineCacheStub(
 #endif  // DEBUG
 
   Label stepping, done_stepping;
-  if (FLAG_support_debugger) {
+  if (FLAG_support_debugger && !optimized) {
     __ Comment("Check single stepping");
     __ LoadIsolate(R6);
     __ ldrb(R6, Address(R6, Isolate::single_step_offset()));
@@ -1507,7 +1508,7 @@ void StubCode::GenerateNArgsCheckInlineCacheStub(
     __ bx(R2);
   }
 
-  if (FLAG_support_debugger) {
+  if (FLAG_support_debugger && !optimized) {
     __ Bind(&stepping);
     __ EnterStubFrame();
     __ Push(R5);  // Preserve IC data.
@@ -1600,7 +1601,7 @@ void StubCode::GenerateOneArgOptimizedCheckInlineCacheStub(
   GenerateOptimizedUsageCounterIncrement(assembler);
   GenerateNArgsCheckInlineCacheStub(assembler, 1,
       kInlineCacheMissHandlerOneArgRuntimeEntry, Token::kILLEGAL,
-      kIgnoreRanges);
+      kIgnoreRanges, true /* optimized */);
 }
 
 
@@ -1609,7 +1610,7 @@ void StubCode::GenerateTwoArgsOptimizedCheckInlineCacheStub(
   GenerateOptimizedUsageCounterIncrement(assembler);
   GenerateNArgsCheckInlineCacheStub(assembler, 2,
       kInlineCacheMissHandlerTwoArgsRuntimeEntry, Token::kILLEGAL,
-      kIgnoreRanges);
+      kIgnoreRanges, true /* optimized */);
 }