[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #7 from rguenth at gcc dot gnu dot org  2008-11-26 09:47 ---
Subject: Bug 37869

Author: rguenth
Date: Wed Nov 26 09:46:23 2008
New Revision: 142213

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=142213
Log:
2008-11-25  Daniel Berlin  [EMAIL PROTECTED]
Richard Guenther  [EMAIL PROTECTED]

PR tree-optimization/37869
* tree-ssa-structalias.c (struct constraint_graph): Remove
pt_used and number_incoming members.
(build_pred_graph): Do not allocate them.
(condense_visit): Do not use them.
(label_visit): Likewise.
(free_var_substitution_info): Do not free them.

Modified:
trunk/gcc/ChangeLog
trunk/gcc/tree-ssa-structalias.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #6 from rguenth at gcc dot gnu dot org  2008-11-26 09:47 ---
Fixed.


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rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
  Known to fail||4.3.2
  Known to work||4.4.0
 Resolution||FIXED
   Target Milestone|--- |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #1 from rguenth at gcc dot gnu dot org  2008-11-25 11:58 ---
Simpler testcase at -O

void
foo (unsigned long *start, unsigned long *end)
{
  unsigned long *temp = end - 1;

  while (end  start)
*end-- = *temp--;
}

blocks alias-improvements branch (causes the store and load to be deleted).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #2 from rguenth at gcc dot gnu dot org  2008-11-25 12:22 ---
On the branch I am installing the following as a stop-gap measure:

Index: tree-ssa-structalias.c
===
--- tree-ssa-structalias.c  (revision 142149)
+++ tree-ssa-structalias.c  (working copy)
@@ -230,6 +230,9 @@ struct variable_info
  variable.  This is used for C++ placement new.  */
   unsigned int no_tbaa_pruning : 1;

+  /* If found to be a non-pointer variable.  */
+  unsigned int is_nonpointer_var : 1;
+
   /* Variable id this was collapsed to due to type unsafety.  Zero if
  this variable was not collapsed.  This should be unused completely
  after build_succ_graph, or something is broken.  */
@@ -377,6 +380,7 @@ new_var_info (tree t, unsigned int id, c
   ret-is_special_var = false;
   ret-is_unknown_size_var = false;
   ret-is_full_var = false;
+  ret-is_nonpointer_var = false;
   var = t;
   if (TREE_CODE (var) == SSA_NAME)
 var = SSA_NAME_VAR (var);
@@ -2175,6 +2179,7 @@ perform_var_substitution (constraint_gra
 %s is a non-pointer variable, eliminating edges.\n,
 get_varinfo (node)-name);
  stats.nonpointer_vars++;
+ get_varinfo (i)-is_nonpointer_var = true;
  clear_edges_for_node (graph, node);
}
 }
@@ -4752,6 +4755,11 @@ find_what_p_points_to (tree p)
   if (vi-is_artificial_var)
return false;

+  /* ???  Some real variables get eliminated as non-pointers.
+Workaround this.  See PR37869.  */
+  if (vi-is_nonpointer_var)
+   return false;
+
   /* See if this is a field or a structure.  */
   if (vi-size != vi-fullsize)
{


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #3 from rguenth at gcc dot gnu dot org  2008-11-25 20:29 ---
Subject: Bug 37869

Author: rguenth
Date: Tue Nov 25 20:27:44 2008
New Revision: 142202

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=142202
Log:
2008-11-25  Richard Guenther  [EMAIL PROTECTED]

* tree-data-ref.c (dr_may_alias_p): Use the alias-oracle.

* tree-tailcall.c (tree_optimize_tail_calls_1): Also split the
edge from the entry block if we have degenerate PHI nodes in
the first basic block.

* gimple.c (gimple_set_bb): Fix off-by-one error.
* tree-cfg.c (move_block_to_fn): Likewise.

PR tree-optimization/37869
* tree-ssa-structalias.c (struct variable_info): Add
is_nonpointer_var flag.
(new_var_info): Clear it.
(perform_var_substitution): Set it.
(find_what_p_points_to): Use it.

Modified:
branches/alias-improvements/gcc/ChangeLog.alias
branches/alias-improvements/gcc/gimple.c
branches/alias-improvements/gcc/tree-cfg.c
branches/alias-improvements/gcc/tree-data-ref.c
branches/alias-improvements/gcc/tree-ssa-structalias.c
branches/alias-improvements/gcc/tree-tailcall.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #4 from rguenth at gcc dot gnu dot org  2008-11-25 21:23 ---
Testcase from comment #1 has wrong points-to sets on the trunk as well (-O).

end = NONLOCAL
temp_4 = end
end_7 = end_1
temp_8 = temp_2
end_1 = end
end_1 = end_7
temp_2 = temp_4
temp_2 = temp_8

...

end_7 is a non-pointer variable, eliminating edges.
end_7 is a non-pointer variable, eliminating edges.
end_7 is a non-pointer variable,ignoring constraint:end_7 = end_1
end_1 is a non-pointer variable,ignoring constraint:end_1 = end
end_1 is a non-pointer variable,ignoring constraint:end_1 = end_7

...

end_7 = { }
end_1 = { }

...


bb 2:
  temp_4 = end_3(D) + -4;
  goto bb 4;

bb 3:
  D.1238_6 = *temp_2;
  *end_1 = D.1238_6;
  end_7 = end_1 + -4;
  temp_8 = temp_2 + -4;

bb 4:
  # end_1 = PHI end_3(D)(2), end_7(3)
  # temp_2 = PHI temp_4(2), temp_8(3)
  if (end_1  start_5(D))
goto bb 3;
  else
goto bb 5;


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869

[Bug tree-optimization/37869] PTA results wrong for non-pointer variables

[rguenth at gcc dot gnu dot org]

--- Comment #5 from rguenth at gcc dot gnu dot org  2008-11-25 21:45 ---
Simpler testcase:

void
foo (unsigned long *end)
{
  unsigned long *temp = end - 1;

  while (1)
*end-- = *temp;
}


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37869