Refactor load forwarding pass to use a Place abstraction.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 919 matching lines @@
 
 
 void JoinEntryInstr::InsertPhi(PhiInstr* phi) {
   // Lazily initialize the array of phis.
   if (phis_ == NULL) {
     phis_ = new ZoneGrowableArray<PhiInstr*>(1);
   }
   phis_->Add(phi);
 }
 
+void JoinEntryInstr::RemovePhi(PhiInstr* phi) {
+  ASSERT(phis_ != NULL);
+  intptr_t to_index = 0;
+  for (intptr_t from_index = 0; from_index < phis_->length(); ++from_index) {

[Kevin Millikin (Google), 2013/06/25 09:18:29]

Is this better than searching for the phi and replacing it with the last
element, unless it is the last element?

[Vyacheslav Egorov (Google), 2013/06/25 18:02:39]

Done.

+    PhiInstr* current = (*phis_)[from_index];
+    if (phi != current) {
+      if (to_index != from_index) {
+        (*phis_)[to_index] = current;
+      }
+      to_index++;
+    }
+  }
+  phis_->RemoveLast();
+}
 
 void JoinEntryInstr::RemoveDeadPhis(Definition* replacement) {
   if (phis_ == NULL) return;
 
   intptr_t to_index = 0;
   for (intptr_t from_index = 0; from_index < phis_->length(); ++from_index) {
     PhiInstr* phi = (*phis_)[from_index];
     if (phi != NULL) {
       if (phi->is_alive()) {
         (*phis_)[to_index++] = phi;
@@ skipping 1599 matching lines @@
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
 #undef __
 
 }  // namespace dart