src/share/vm/opto/opaquenode.cpp

rev 7345 : 8054478: C2: Incorrectly compiled char[] array access crashes JVM
Summary: propagate node replacements along control flow edges to callers
Reviewed-by: dead backbranch in main loop results in erroneous array access
rev 7347 : reviews

*** 21,48 ****
   * questions.
   *
   */
  
  #include "precompiled.hpp"
  #include "opto/opaquenode.hpp"
  #include "opto/phaseX.hpp"
  
  //=============================================================================
  // Do not allow value-numbering
  uint Opaque1Node::hash() const { return NO_HASH; }
! uint Opaque1Node::cmp( const Node &n ) const {
    return (&n == this);          // Always fail except on self
  }
  
  //------------------------------Identity---------------------------------------
  // If _major_progress, then more loop optimizations follow.  Do NOT remove
  // the opaque Node until no more loop ops can happen.  Note the timing of
  // _major_progress; it's set in the major loop optimizations THEN comes the
  // call to IterGVN and any chance of hitting this code.  Hence there's no
  // phase-ordering problem with stripping Opaque1 in IGVN followed by some
  // more loop optimizations that require it.
! Node *Opaque1Node::Identity( PhaseTransform *phase ) {
    return phase->C->major_progress() ? this : in(1);
  }
  
  //=============================================================================
  // A node to prevent unwanted optimizations.  Allows constant folding.  Stops
--- 21,49 ----
   * questions.
   *
   */
  
  #include "precompiled.hpp"
+ #include "opto/loopnode.hpp"
  #include "opto/opaquenode.hpp"
  #include "opto/phaseX.hpp"
  
  //=============================================================================
  // Do not allow value-numbering
  uint Opaque1Node::hash() const { return NO_HASH; }
! uint Opaque1Node::cmp(const Node &n) const {
    return (&n == this);          // Always fail except on self
  }
  
  //------------------------------Identity---------------------------------------
  // If _major_progress, then more loop optimizations follow.  Do NOT remove
  // the opaque Node until no more loop ops can happen.  Note the timing of
  // _major_progress; it's set in the major loop optimizations THEN comes the
  // call to IterGVN and any chance of hitting this code.  Hence there's no
  // phase-ordering problem with stripping Opaque1 in IGVN followed by some
  // more loop optimizations that require it.
! Node *Opaque1Node::Identity(PhaseTransform *phase) {
    return phase->C->major_progress() ? this : in(1);
  }
  
  //=============================================================================
  // A node to prevent unwanted optimizations.  Allows constant folding.  Stops