Improve ShouldSpecializeForDouble to handle ICs with multiple checks.

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 05707fe79a51e35209d3060aecdad3cb6a7c65bb..2bce3fe8fe0dae083ca945c2a74d137f2b6e469d 100644
--- a/runtime/vm/flow_graph_optimizer.cc
+++ b/runtime/vm/flow_graph_optimizer.cc
@@ -266,22 +266,29 @@ static bool HasOneDouble(const ICData& ic_data) {
 
 
 static bool ShouldSpecializeForDouble(const ICData& ic_data) {
-  if (ic_data.NumberOfChecks() != 1) return false;
+  if (ic_data.NumberOfChecks() < 1) return false;
   if (ic_data.num_args_tested() != 2) return false;
 
-  Function& target = Function::Handle();
-  GrowableArray<intptr_t> class_ids;
-  ic_data.GetCheckAt(0, &class_ids, &target);
-  ASSERT(class_ids.length() == 2);
+  for (intptr_t check_idx = 0;
+       check_idx < ic_data.NumberOfChecks();
+       check_idx++) {
+    Function& target = Function::Handle();
+    GrowableArray<intptr_t> class_ids;
+    ic_data.GetCheckAt(check_idx, &class_ids, &target);
+    ASSERT(class_ids.length() == 2);
 
-  const bool seen_double =
-      (class_ids[0] == kDoubleCid) || (class_ids[1] == kDoubleCid);
+    const bool seen_double =

[Florian Schneider, 2012/09/21 13:23:07]

It would be nice to have a helper that checks for at the combinations of
smi/double with least one double.

+        (class_ids[0] == kDoubleCid) || (class_ids[1] == kDoubleCid);
 
-  const bool seen_only_smi_or_double =
-      ((class_ids[0] == kDoubleCid) || (class_ids[0] == kSmiCid)) &&
-      ((class_ids[1] == kDoubleCid) || (class_ids[1] == kSmiCid));
+    const bool seen_only_smi_or_double =
+        ((class_ids[0] == kDoubleCid) || (class_ids[0] == kSmiCid)) &&
+        ((class_ids[1] == kDoubleCid) || (class_ids[1] == kSmiCid));
 
-  return seen_double && seen_only_smi_or_double;
+    if (!seen_double || !seen_only_smi_or_double) {
+      return false;
+    }
+  }
+  return true;
 }