VM: Use propagated type to improve checked smi operations in aot compiler.

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
diff --git a/runtime/vm/intermediate_language_arm64.cc b/runtime/vm/intermediate_language_arm64.cc
index cb225a2ac6b79183f2aa8962af8c23bf21bc4ba3..56d388298348c01fbc442a59ce67a599b04be714 100644
--- a/runtime/vm/intermediate_language_arm64.cc
+++ b/runtime/vm/intermediate_language_arm64.cc
@@ -2809,8 +2809,19 @@ void CheckedSmiOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register left = locs()->in(0).reg();
   Register right = locs()->in(1).reg();
   Register result = locs()->out(0).reg();
-  __ orr(result, left, Operand(right));
-  __ tsti(result, Immediate(kSmiTagMask));
+  intptr_t left_cid = this->left()->Type()->ToCid();
+  intptr_t right_cid = this->right()->Type()->ToCid();
+  bool combined_smi_check = false;
+  if (left_cid == kSmiCid) {

[rmacnak, 2016/03/22 16:46:16]

Missing same definition case.

[Florian Schneider, 2016/03/22 17:02:44]

Done here and for CheckEitherNonSmiInstr as well.

+    __ tsti(right, Immediate(kSmiTagMask));
+  } else if (right_cid == kSmiCid) {
+    __ tsti(left, Immediate(kSmiTagMask));
+  } else {
+    combined_smi_check = true;
+    __ orr(result, left, Operand(right));
+    __ tsti(result, Immediate(kSmiTagMask));
+  }
+
   __ b(slow_path->entry_label(), NE);
   switch (op_kind()) {
     case Token::kADD:
@@ -2822,7 +2833,10 @@ void CheckedSmiOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
       __ b(slow_path->entry_label(), VS);
       break;
     case Token::kBIT_OR:
-      // Operation part of combined smi check.
+      // Operation may be part of combined smi check.
+      if (!combined_smi_check) {
+        __ orr(result, left, Operand(right));
+      }
       break;
     case Token::kBIT_AND:
       __ and_(result, left, Operand(right));