Implement SmiToInt and DoubleToInt.

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 13385)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -887,7 +887,7 @@
   ASSERT(call->HasICData());
   const ICData& ic_data = *call->ic_data();
   if ((ic_data.NumberOfChecks() == 0) || !ic_data.HasOneTarget()) {
-    // No type feedback collected.
+    // No type feedback collected or multiple targets found.
     return false;
   }
   Function& target = Function::Handle();
@@ -914,6 +914,31 @@
     return true;
   }
 
+  if ((recognized_kind == MethodRecognizer::kIntegerToInteger) &&
+      (class_ids[0] == kSmiCid)) {
+    // TODO(srdjan): implement also for BigInt and Mint.
+    InsertBefore(call,
+                 new CheckSmiInstr(call->ArgumentAt(0)->value()->Copy(),
+                                   call->deopt_id()),
+                 call->env(),
+                 Definition::kEffect);
+    IntegerToIntegerInstr* int2int_instr =
+        new IntegerToIntegerInstr(call->ArgumentAt(0)->value(), call, kSmiCid);
+    call->ReplaceWith(int2int_instr, current_iterator());

[Florian Schneider, 2012/10/09 11:13:58]

Since IntegerToInteger itself is a nop, I think you can avoid having an extra IL
instruction for Integer.toInt. Just do a CheckSmi/ClassCheck and then replace
all uses of the call with the input:

call->ReplaceUsesWith(call->ArgumentAt(0)->value());

[srdjan, 2012/10/09 21:23:04]

Done.

+    RemovePushArguments(call);
+    return true;
+  }
+
+  if ((recognized_kind == MethodRecognizer::kDoubleToInteger) &&
+      (class_ids[0] == kDoubleCid)) {
+    AddCheckClass(call, call->ArgumentAt(0)->value()->Copy());
+    DoubleToIntegerInstr* d2int_instr = new DoubleToIntegerInstr(call);
+    call->ReplaceWith(d2int_instr, current_iterator());
+    // Pushed arguments are not removed because DoubleToInt is implemented
+    // as a call.
+    return true;
+  }
+
   if (recognized_kind == MethodRecognizer::kStringBaseIsEmpty) {
     if (!ic_data.HasOneTarget()) {
       // Target is not only StringBase_get_length.
@@ -927,6 +952,8 @@
 }
 
 
+// Tries to optimize instance call by replacing it with a faster instruction
+// (e.g, binary op, field load, ..).
 void FlowGraphOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
   if (instr->HasICData() && (instr->ic_data()->NumberOfChecks() > 0)) {
     const Token::Kind op_kind = instr->token_kind();
@@ -3049,6 +3076,23 @@
 }
 
 
+void ConstantPropagator::VisitIntegerToInteger(IntegerToIntegerInstr* instr) {
+  const Object& value = instr->value()->definition()->constant_value();
+  if (IsNonConstant(value)) {
+    SetValue(instr, non_constant_);
+  } else if (IsConstant(value)) {
+    // TODO(kmillikin): Handle conversion.
+    SetValue(instr, non_constant_);
+  }
+}
+
+
+void ConstantPropagator::VisitDoubleToInteger(DoubleToIntegerInstr* instr) {
+  // TODO(kmillikin): Handle conversion.
+  SetValue(instr, non_constant_);
+}
+
+
 void ConstantPropagator::VisitConstant(ConstantInstr* instr) {
   SetValue(instr, instr->value());
 }