VM: Support phis with pair representations.

runtime/vm/il_printer.cc

 // Copyright (c) 2012, 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/il_printer.h"
 
 #include "vm/flow_graph_range_analysis.h"
 #include "vm/intermediate_language.h"
 #include "vm/os.h"
 #include "vm/parser.h"
@@ skipping 1032 matching lines @@
     case kNoRepresentation:
       return "none";
     case kNumRepresentations:
       UNREACHABLE();
   }
   return "?";
 }
 
 
 void PhiInstr::PrintTo(BufferFormatter* f) const {
-  f->Print("v%" Pd " <- phi(", ssa_temp_index());
+  if (HasPairRepresentation()) {
+    f->Print("(v%" Pd ", v%" Pd ") <- phi(",
+             ssa_temp_index(), ssa_temp_index() + 1);
+  } else {
+    f->Print("v%" Pd " <- phi(", ssa_temp_index());
+  }
   for (intptr_t i = 0; i < inputs_.length(); ++i) {
     if (inputs_[i] != NULL) inputs_[i]->PrintTo(f);
     if (i < inputs_.length() - 1) f->Print(", ");
   }
   f->Print(")");
   if (is_alive()) {
     f->Print(" alive");
   } else {
     f->Print(" dead");
   }
@@ skipping 148 matching lines @@
 }
 
 const char* Environment::ToCString() const {
   char buffer[1024];
   BufferFormatter bf(buffer, 1024);
   PrintTo(&bf);
   return Thread::Current()->zone()->MakeCopyOfString(buffer);
 }
 
 }  // namespace dart