Fix a representation change bug in the Hydrogen graph construction.

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1795 matching lines @@
   }
 }
 
 
 void HGraph::InsertRepresentationChangeForUse(HValue* value,
                                               HValue* use,
                                               Representation to,
                                               bool is_truncating) {
   // Insert the representation change right before its use. For phi-uses we
   // insert at the end of the corresponding predecessor.
-  HBasicBlock* insert_block = use->block();
+  HInstruction* next = NULL;
   if (use->IsPhi()) {
     int index = 0;
     while (use->OperandAt(index) != value) ++index;
-    insert_block = insert_block->predecessors()->at(index);
+    next = use->block()->predecessors()->at(index)->end();
+  } else {
+    next = HInstruction::cast(use);
   }
 
-  HInstruction* next = (insert_block == use->block())
-      ? HInstruction::cast(use)
-      : insert_block->end();
-
   // For constants we try to make the representation change at compile
   // time. When a representation change is not possible without loss of
   // information we treat constants like normal instructions and insert the
   // change instructions for them.
   HInstruction* new_value = NULL;
   if (value->IsConstant()) {
     HConstant* constant = HConstant::cast(value);
     // Try to create a new copy of the constant with the new representation.
     new_value = is_truncating
         ? constant->CopyToTruncatedInt32()
@@ skipping 4141 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal