VM: Improve polymorphic check-class in optimized code.

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/dart_entry.h"
@@ skipping 5494 matching lines @@
                      Object::null_object(), PP);
     __ j(EQUAL, deopt);
     return;
   }
 
   ASSERT((unary_checks().GetReceiverClassIdAt(0) != kSmiCid) ||
          (unary_checks().NumberOfChecks() > 1));
   Register value = locs()->in(0).reg();
   Register temp = locs()->temp(0).reg();
   Label is_ok;
-  intptr_t cix = 0;
-  if (unary_checks().GetReceiverClassIdAt(cix) == kSmiCid) {
+  if (unary_checks().GetReceiverClassIdAt(0) == kSmiCid) {
     __ testq(value, Immediate(kSmiTagMask));
     __ j(ZERO, &is_ok);
-    cix++;  // Skip first check.
   } else {
     __ testq(value, Immediate(kSmiTagMask));
     __ j(ZERO, deopt);
   }
   __ LoadClassId(temp, value);
 
   if (IsDenseSwitch()) {
     ASSERT(cids_[0] < cids_[cids_.length() - 1]);
     __ subq(temp, Immediate(cids_[0]));
     __ cmpq(temp, Immediate(cids_[cids_.length() - 1] - cids_[0]));
     __ j(ABOVE, deopt);
 
     intptr_t mask = ComputeCidMask();
     if (!IsDenseMask(mask)) {
       // Only need mask if there are missing numbers in the range.
       ASSERT(cids_.length() > 2);
       Register mask_reg = locs()->temp(1).reg();
       __ movq(mask_reg, Immediate(mask));
       __ btq(mask_reg, temp);
       __ j(NOT_CARRY, deopt);
     }
   } else {
-    const intptr_t num_checks = unary_checks().NumberOfChecks();
+    GrowableArray<CidTarget> sorted_ic_data;
+    FlowGraphCompiler::SortICDataByCount(unary_checks(),
+                                         &sorted_ic_data,
+                                         /* drop_smi = */ true);
+    const intptr_t num_checks = sorted_ic_data.length();
     const bool use_near_jump = num_checks < 5;
-    for (intptr_t i = cix; i < num_checks; i++) {
-      ASSERT(unary_checks().GetReceiverClassIdAt(i) != kSmiCid);
-      __ cmpl(temp, Immediate(unary_checks().GetReceiverClassIdAt(i)));
+    for (intptr_t i = 0; i < num_checks; i++) {
+      const intptr_t cid = sorted_ic_data[i].cid;
+      __ cmpl(temp, Immediate(cid));
       if (i == (num_checks - 1)) {
         __ j(NOT_EQUAL, deopt);
       } else {
         if (use_near_jump) {
           __ j(EQUAL, &is_ok, Assembler::kNearJump);
         } else {
           __ j(EQUAL, &is_ok);
         }
       }
     }
@@ skipping 883 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64