src/share/vm/opto/connode.cpp

rev 6132 : 8031755: Type speculation should be used to optimize explicit null checks
Summary: feed profiling data about reference nullness to type speculation.
Reviewed-by:

*** 397,407 ****
  
  //------------------------------Value------------------------------------------
  // Take 'join' of input and cast-up type
  const Type *ConstraintCastNode::Value( PhaseTransform *phase ) const {
    if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
! const Type* ft = phase->type(in(1))->filter_speculative(_type);
  
  #ifdef ASSERT
    // Previous versions of this function had some special case logic,
    // which is no longer necessary.  Make sure of the required effects.
    switch (Opcode()) {
--- 397,407 ----
  
  //------------------------------Value------------------------------------------
  // Take 'join' of input and cast-up type
  const Type *ConstraintCastNode::Value( PhaseTransform *phase ) const {
    if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
!   const Type* ft = phase->type(in(1))->filter_speculative(_type);
  
  #ifdef ASSERT
    // Previous versions of this function had some special case logic,
    // which is no longer necessary.  Make sure of the required effects.
    switch (Opcode()) {
*** 491,501 ****
          : in_type;
      } else {
        result =  my_type->cast_to_ptr_type( my_type->join_ptr(in_ptr) );
      }
    }
!   return result;
  
    // JOIN NOT DONE HERE BECAUSE OF INTERFACE ISSUES.
    // FIX THIS (DO THE JOIN) WHEN UNION TYPES APPEAR!
  
    //
--- 491,511 ----
          : in_type;
      } else {
        result =  my_type->cast_to_ptr_type( my_type->join_ptr(in_ptr) );
      }
    }
! 
!   // This is the code from TypePtr::xmeet() that prevents us from
!   // having 2 ways to represent the same type. We have to replicate it
!   // here because we don't go through meet/join.
!   if (result->remove_speculative() == result->speculative()) {
!     result = result->remove_speculative();
!   }
! 
!   // Same as above: because we don't go through meet/join, remove the
!   // speculative type if we know we won't use it.
!   return result->cleanup_speculative();
  
    // JOIN NOT DONE HERE BECAUSE OF INTERFACE ISSUES.
    // FIX THIS (DO THE JOIN) WHEN UNION TYPES APPEAR!
  
    //