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Re: [tree-ssa] Out of SSA status and issues

In message <1052759521.3373.0.camel@p4>, Andrew MacLeod writes:
 >> FWIW, I dug up my changes to identify the problem variables (those
 >> occurring in abnormal PHIs) and cobbled together the two lines of
 >> code necessary to use that information to avoid copy propagating
 >> those variables during SSA renaming.
 >> 
 >> Interested in playing with it to see if it resolves your problems?
 >> 
 >Absolutely :-)

Here you go.  Feel free to check it in if it resolves the problems to
your satisfaction.


	* tree-flow.h (struct var_ann_d): New field occurs_in_abnormal_phi.
	* tree-ssa.c (MAY_COPYPROP_P): Do not allow copy propagations
	if either argument occurs in an abnormal phi.
	* tree-dfa.c (add_phi_arg): Set occurs_in_abrnomal_phi as needed.
	* tree-ssa-copyprop.c (copyprop_stmt): Do not allow copy
	propagations if either argument occurs in an abnormal phi.
	(copyprop_phi): Likewise.
	

Index: tree-flow.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-flow.h,v
retrieving revision 1.1.4.77
diff -c -3 -p -r1.1.4.77 tree-flow.h
*** tree-flow.h	8 May 2003 20:29:29 -0000	1.1.4.77
--- tree-flow.h	12 May 2003 17:18:10 -0000
*************** struct var_ann_d GTY(())
*** 93,100 ****
    /* Used when building root_var structures in tree_ssa_live.[ch].  */
    unsigned root_var_processed : 1;
  
    /* Unused bits.  */
!   unsigned unused : 24;
  
    /* An INDIRECT_REF expression representing all the dereferences of this
       pointer.  Used to store aliasing information for pointer dereferences
--- 93,103 ----
    /* Used when building root_var structures in tree_ssa_live.[ch].  */
    unsigned root_var_processed : 1;
  
+   /* Nonzero if the variable occurs in an abnormal PHI.  */
+   unsigned occurs_in_abnormal_phi : 1;
+ 
    /* Unused bits.  */
!   unsigned unused : 23;
  
    /* An INDIRECT_REF expression representing all the dereferences of this
       pointer.  Used to store aliasing information for pointer dereferences
Index: tree-ssa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa.c,v
retrieving revision 1.1.4.75
diff -c -3 -p -r1.1.4.75 tree-ssa.c
*** tree-ssa.c	8 May 2003 20:29:30 -0000	1.1.4.75
--- tree-ssa.c	12 May 2003 17:19:20 -0000
*************** static bool var_is_live			PARAMS ((tree,
*** 226,232 ****
  	   && TREE_CODE (SSA_NAME_VAR (RHS)) == INDIRECT_REF)		\
       /* FIXME.  For now, don't propagate pointers if they haven't been	\
          dereferenced (see update_indirect_ref_vuses).  */		\
!      && (!POINTER_TYPE_P (TREE_TYPE (RHS)) || indirect_ref (RHS)))
  
  
  /* Main entry point to the SSA builder.  FNDECL is the gimplified function
--- 226,234 ----
  	   && TREE_CODE (SSA_NAME_VAR (RHS)) == INDIRECT_REF)		\
       /* FIXME.  For now, don't propagate pointers if they haven't been	\
          dereferenced (see update_indirect_ref_vuses).  */		\
!      && (!POINTER_TYPE_P (TREE_TYPE (RHS)) || indirect_ref (RHS))	\
!      && ! var_ann (SSA_NAME_VAR (LHS))->occurs_in_abnormal_phi		\
!      && ! var_ann (SSA_NAME_VAR (RHS))->occurs_in_abnormal_phi)
  
  
  /* Main entry point to the SSA builder.  FNDECL is the gimplified function
Index: tree-dfa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-dfa.c,v
retrieving revision 1.1.4.111
diff -c -3 -p -r1.1.4.111 tree-dfa.c
*** tree-dfa.c	8 May 2003 20:29:29 -0000	1.1.4.111
--- tree-dfa.c	12 May 2003 17:19:22 -0000
*************** add_phi_arg (phi, def, e)
*** 937,942 ****
--- 937,951 ----
    if (i >= PHI_ARG_CAPACITY (phi))
      abort ();
  #endif
+ 
+   /* Copy propagation needs to know what object occur in abnormal
+      PHI nodes.  This is a convenient place to record such information.  */
+   if (e->flags & EDGE_ABNORMAL)
+     {
+       var_ann (def)->occurs_in_abnormal_phi = 1;
+       var_ann (PHI_RESULT (phi))->occurs_in_abnormal_phi = 1;
+     }
+ 
    PHI_ARG_DEF (phi, i) = def;
    PHI_ARG_EDGE (phi, i) = e;
    PHI_NUM_ARGS (phi)++;
Index: tree-ssa-copyprop.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa-copyprop.c,v
retrieving revision 1.1.2.1
diff -c -3 -p -r1.1.2.1 tree-ssa-copyprop.c
*** tree-ssa-copyprop.c	1 Mar 2003 00:09:07 -0000	1.1.2.1
--- tree-ssa-copyprop.c	12 May 2003 17:19:22 -0000
*************** copyprop_stmt (stmt)
*** 114,120 ****
        tree *use_p = (tree *) VARRAY_GENERIC_PTR (uses, i);
        tree orig = get_original (*use_p, &vuse);
  
!       if (orig)
  	{
  	  if (dump_file && (dump_flags & TDF_DETAILS))
  	    {
--- 114,122 ----
        tree *use_p = (tree *) VARRAY_GENERIC_PTR (uses, i);
        tree orig = get_original (*use_p, &vuse);
  
!       if (orig
! 	  && ! var_ann (SSA_NAME_VAR (*use_p))->occurs_in_abnormal_phi
! 	  && ! var_ann (SSA_NAME_VAR (orig))->occurs_in_abnormal_phi)
  	{
  	  if (dump_file && (dump_flags & TDF_DETAILS))
  	    {
*************** copyprop_phi (phi)
*** 159,165 ****
        tree arg = PHI_ARG_DEF (phi, i);
        tree orig = get_original (arg, &vuse);
  
!       if (orig)
  	{
  	  if (dump_file && dump_flags & TDF_DETAILS)
  	    {
--- 161,169 ----
        tree arg = PHI_ARG_DEF (phi, i);
        tree orig = get_original (arg, &vuse);
  
!       if (orig
! 	  && ! var_ann (SSA_NAME_VAR (arg))->occurs_in_abnormal_phi
! 	  && ! var_ann (SSA_NAME_VAR (orig))->occurs_in_abnormal_phi)
  	{
  	  if (dump_file && dump_flags & TDF_DETAILS)
  	    {
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