Added flag --inline_smi_string_hashcode and --inline_smi_string_hashcode_ratio to decide when/if sh…

runtime/vm/flow_graph_compiler_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1312 matching lines @@
   const Array& arguments_descriptor =
       Array::ZoneHandle(zone(), ic_data.arguments_descriptor());
   ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
   const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(zone(),
       MegamorphicCacheTable::Lookup(isolate(), name, arguments_descriptor));
 
   __ Comment("MegamorphicCall");
   // Load receiver into T0,
   __ lw(T0, Address(SP, (argument_count - 1) * kWordSize));
   Label done;
-  if (name.raw() == Symbols::hashCode().raw()) {
-    Label try_onebytestring, megamorphic_call;
+  if (ShouldInlineSmiStringHashCode(ic_data)) {
+    Label megamorphic_call;
     __ Comment("Inlined get:hashCode for Smi and OneByteString");
+    __ mov(V0, T0);  // Move Smi hashcode to V0.
     __ andi(CMPRES1, T0, Immediate(kSmiTagMask));
-    __ bne(CMPRES1, ZR, &try_onebytestring);  // Not Smi.
-    __ mov(V0, T0);
-    __ b(&done);
+    __ beq(CMPRES1, ZR, &done);  // Is Smi.

[zra, 2016/04/27 16:28:17]

The mov can go in the branch delay slot:

__ beq(CMPRES1, ZR, &done);
__ delay_slot()->mov(V0, T0);

[srdjan, 2016/04/27 18:10:22]

Done.

 
-    __ Bind(&try_onebytestring);
     __ LoadClassId(CMPRES1, T0);  // Class ID check.
     __ BranchNotEqual(
         CMPRES1, Immediate(kOneByteStringCid), &megamorphic_call);
 
     __ lw(V0, FieldAddress(T0, String::hash_offset()));
     __ bne(V0, ZR, &done);
 
     __ Bind(&megamorphic_call);
     __ Comment("Slow case: megamorphic call");
   }
@@ skipping 610 matching lines @@
   __ AddImmediate(SP, kDoubleSize);
 }
 
 
 #undef __
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS