With --noopt run unoptimized code through optimizer, more optimizations can be done later.

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
diff --git a/runtime/vm/flow_graph_optimizer.cc b/runtime/vm/flow_graph_optimizer.cc
index ee53c720bc33e2349c786fe03aa3ced02a6bd3c2..8dc704804c721a7acc95e39be83101eb1f8ded9b 100644
--- a/runtime/vm/flow_graph_optimizer.cc
+++ b/runtime/vm/flow_graph_optimizer.cc
@@ -6,6 +6,7 @@
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
+#include "vm/compiler.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
@@ -87,6 +88,34 @@ void FlowGraphOptimizer::ApplyICData() {
 }
 
 
+void FlowGraphOptimizer::PopulateWithICData() {
+  ASSERT(current_iterator_ == NULL);
+  for (intptr_t i = 0; i < block_order_.length(); ++i) {
+    BlockEntryInstr* entry = block_order_[i];
+    ForwardInstructionIterator it(entry);
+    current_iterator_ = &it;

[Florian Schneider, 2015/05/21 14:51:05]

I don't think you need to use the current_iterator_ here since no instructions
are added/removed during iteration.

[srdjan, 2015/05/21 17:27:07]

Done.

+    for (; !it.Done(); it.Advance()) {
+      Instruction* instr = it.Current();
+      if (instr->IsInstanceCall()) {
+        InstanceCallInstr* call = instr->AsInstanceCall();
+        if (!call->HasICData()) {
+          const Array& arguments_descriptor =
+              Array::Handle(zone(),
+                  ArgumentsDescriptor::New(call->ArgumentCount(),
+                                           call->argument_names()));
+          const ICData& ic_data = ICData::ZoneHandle(zone(), ICData::New(
+              function(), call->function_name(),
+              arguments_descriptor, call->deopt_id(),
+              call->checked_argument_count()));
+          call->set_ic_data(&ic_data);
+        }
+      }
+    }
+    current_iterator_ = NULL;
+  }
+}
+
+
 // Optimize instance calls using cid.  This is called after optimizer
 // converted instance calls to instructions. Any remaining
 // instance calls are either megamorphic calls, cannot be optimized or
@@ -162,12 +191,14 @@ bool FlowGraphOptimizer::TryCreateICData(InstanceCallInstr* call) {
       Token::IsBinaryOperator(op_kind)) {
     // Guess cid: if one of the inputs is a number assume that the other
     // is a number of same type.
-    const intptr_t cid_0 = class_ids[0];
-    const intptr_t cid_1 = class_ids[1];
-    if ((cid_0 == kDynamicCid) && (IsNumberCid(cid_1))) {
-      class_ids[0] = cid_1;
-    } else if (IsNumberCid(cid_0) && (cid_1 == kDynamicCid)) {
-      class_ids[1] = cid_0;
+    if (Compiler::guess_other_cid()) {
+      const intptr_t cid_0 = class_ids[0];
+      const intptr_t cid_1 = class_ids[1];
+      if ((cid_0 == kDynamicCid) && (IsNumberCid(cid_1))) {
+        class_ids[0] = cid_1;
+      } else if (IsNumberCid(cid_0) && (cid_1 == kDynamicCid)) {
+        class_ids[1] = cid_0;
+      }
     }
   }
 
@@ -4169,6 +4200,15 @@ void FlowGraphOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
   }
 
   const Token::Kind op_kind = instr->token_kind();
+  if (Compiler::always_optimize()) {
+    // TODO(srdjan): Investigate other attempts, as they are not allowed to
+    // deoptimize.
+    if ((op_kind == Token::kGET) && TryInlineInstanceGetter(instr)) {

[Florian Schneider, 2015/05/21 14:51:05]

How do we guarantee that TryInline... does not introduce a check?

Maybe introduce a separate inline-pass (e.g. TryInlineGetterWithoutCheck)
for always-optimize that does not emit check instructions at all. Ideally it
would share most code with TryInlineInstanceGetter.

[srdjan, 2015/05/21 17:27:07]

Every check adds a deopt stub in case of failure; there is an assert making sure
that we do not emit deopt stubs when 'always_optimize'. It is probably safer to
add ass suggested   TryInlineGetterWithoutCheck. I am actually reusing the
method 'TryInlineGetterWithoutCheck' and passing an argument 'allow_check'.

+      return;
+    }
+    return;
+  }
+
   // Type test is special as it always gets converted into inlined code.
   if (Token::IsTypeTestOperator(op_kind)) {
     ReplaceWithInstanceOf(instr);