For instance call representing numerical comparisons (double and Smi for now) that were never visit…

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 31031)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -62,7 +62,9 @@
 }
 
 
-// Optimize instance calls using cid.
+// Optimize instance calls using cid. This is called after the optimizer which
+// converts instance calls to instructions has been run. Any remaining
+// instance calls probably do not have IC data.
 // Attempts to convert an instance call (IC call) using propagated class-ids,
 // e.g., receiver class id, guarded-cid.
 void FlowGraphOptimizer::ApplyClassIds() {
@@ -96,21 +98,53 @@
 }
 
 
+// TODO(srdjan): write tests for others.
+static bool IsNumberCid(intptr_t cid) {
+  return (cid == kSmiCid) || (cid == kDoubleCid);
+}
+
+static bool NoneIsDynamic(const GrowableArray<intptr_t>& cids) {
+  for (intptr_t i = 0; i < cids.length(); i++) {
+    if (cids[i] == kDynamicCid) {
+      return false;
+    }
+  }
+  return true;
+}
+
+
 // Attempt to build ICData for call using propagated class-ids.
 bool FlowGraphOptimizer::TryCreateICData(InstanceCallInstr* call) {
   ASSERT(call->HasICData());
   if (call->ic_data()->NumberOfChecks() > 0) {
-    // This occurs when an instance call has too many checks.
-    // TODO(srdjan): Replace IC call with megamorphic call.
+    // This occurs when an instance call has too many checks, will be
+    // converted to megamorphic calls.
     return false;
   }
+  // Empty IC data.
   GrowableArray<intptr_t> class_ids(call->ic_data()->num_args_tested());
   ASSERT(call->ic_data()->num_args_tested() <= call->ArgumentCount());
   for (intptr_t i = 0; i < call->ic_data()->num_args_tested(); i++) {
-    intptr_t cid = call->PushArgumentAt(i)->value()->Type()->ToCid();
+    const intptr_t cid = call->PushArgumentAt(i)->value()->Type()->ToCid();
     class_ids.Add(cid);
   }
-  if (class_ids[0] != kDynamicCid) {
+  // We guess that comparison and binary operations typically
+  // have both arguments of the same cid. If only one argument's cid is known,
+  // assume the other argument has the same cid.
+  const Token::Kind op_kind = call->token_kind();
+  if (Token::IsRelationalOperator(op_kind) ||
+      Token::IsEqualityOperator(op_kind) ||
+      Token::IsBinaryOperator(op_kind)) {
+    // If left or right is a number -> make the other a number as well.
+    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 (NoneIsDynamic(class_ids)) {
     ArgumentsDescriptor args_desc(
         Array::Handle(ArgumentsDescriptor::New(call->ArgumentCount(),
                                                call->argument_names())));
@@ -124,10 +158,7 @@
     if (function.IsNull()) {
       return false;
     }
-    // Create new ICData, do not modify the one attached to the instruction
-    // since it is attached to the assembly instruction itself.
-    // TODO(srdjan): Prevent modification of ICData object that is
-    // referenced in assembly code.
+
     ICData& ic_data = ICData::ZoneHandle(ICData::New(
         flow_graph_->parsed_function().function(),
         call->function_name(),
@@ -6906,20 +6937,17 @@
 }
 
 
-void ConstantPropagator::VisitBinaryMintOp(
-    BinaryMintOpInstr* instr) {
+void ConstantPropagator::VisitBinaryMintOp(BinaryMintOpInstr* instr) {
   HandleBinaryOp(instr, instr->op_kind(), *instr->left(), *instr->right());
 }
 
 
-void ConstantPropagator::VisitShiftMintOp(
-    ShiftMintOpInstr* instr) {
+void ConstantPropagator::VisitShiftMintOp(ShiftMintOpInstr* instr) {
   HandleBinaryOp(instr, instr->op_kind(), *instr->left(), *instr->right());
 }
 
 
-void ConstantPropagator::VisitUnaryMintOp(
-    UnaryMintOpInstr* instr) {
+void ConstantPropagator::VisitUnaryMintOp(UnaryMintOpInstr* instr) {
   // TODO(kmillikin): Handle unary operations.
   SetValue(instr, non_constant_);
 }