Shorten live ranges for arguments to runtime calls.

src/lithium.h

 // 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 518 matching lines @@
     return env_->values()->at(current_);
   }
 
   inline void Advance() {
     current_ = AdvanceToNext(current_ + 1);
   }
 
   inline LEnvironment* env() { return env_; }
 
  private:
+  inline bool ShouldSkip(LOperand* op) {
+    return op == NULL || op->IsConstantOperand() || op->IsArgument();

[fschneider, 2011/02/21 17:02:01]

Just wondering: Was this already a problem before to have LArgument operands in
the enumeration of environment uses not skipped?

+  }
+
   inline int AdvanceToNext(int start) {
-    while (start < limit_ &&
-           (env_->values()->at(start) == NULL ||
-            env_->values()->at(start)->IsConstantOperand())) {
+    while (start < limit_ && ShouldSkip(env_->values()->at(start))) {
       start++;
     }
     return start;
   }
 
   LEnvironment* env_;
   int limit_;
   int current_;
 };
 
@@ skipping 28 matching lines @@
   inline void AdvanceToOuter() {
     current_iterator_ = ShallowIterator(current_iterator_.env()->outer());
   }
 
   ShallowIterator current_iterator_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_H_