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

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 2830 matching lines @@
   }
   return summary;
 }
 
 
 void CheckedSmiOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   CheckedSmiSlowPath* slow_path =
       new CheckedSmiSlowPath(this, compiler->CurrentTryIndex());
   compiler->AddSlowPathCode(slow_path);
   // Test operands if necessary.
+
+  intptr_t left_cid = left()->Type()->ToCid();
+  intptr_t right_cid = right()->Type()->ToCid();
   Register left = locs()->in(0).reg();
   Register right = locs()->in(1).reg();
+  if (this->left()->definition() == this->right()->definition()) {
+    __ testq(left, Immediate(kSmiTagMask));
+  } else if (left_cid == kSmiCid) {
+    __ testq(right, Immediate(kSmiTagMask));
+  } else if (right_cid == kSmiCid) {
+    __ testq(left, Immediate(kSmiTagMask));
+  } else {
+    __ movq(TMP, left);
+    __ orq(TMP, right);
+    __ testq(TMP, Immediate(kSmiTagMask));
+  }
+  __ j(NOT_ZERO, slow_path->entry_label());
   Register result = locs()->out(0).reg();
-  __ movq(TMP, left);
-  __ orq(TMP, right);
-  __ testq(TMP, Immediate(kSmiTagMask));
-  __ j(NOT_ZERO, slow_path->entry_label());
   switch (op_kind()) {
     case Token::kADD:
       __ movq(result, left);
       __ addq(result, right);
       __ j(OVERFLOW, slow_path->entry_label());
       break;
     case Token::kSUB:
       __ movq(result, left);
       __ subq(result, right);
       __ j(OVERFLOW, slow_path->entry_label());
@@ skipping 3639 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64