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Re: [vta, graphite?] propagate degenerate phi nodes into debug stmts
On Nov 19, 2009, Richard Guenther <richard.guenther@gmail.com> wrote:
> On Thu, Nov 19, 2009 at 5:27 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Nov 17, 2009, Richard Guenther <richard.guenther@gmail.com> wrote:
>>
>>> Well, just adjust degenerate_phi_result to do instead of calling
>>> operand_equal_p
>>
>>> Â else if (TREE_CODE (arg) != TREE_CODE (val)
>>> Â Â Â Â Â Â Â|| (TREE_CODE (arg) == SSA_NAME
>>> Â Â Â Â Â Â Â Â Â&& arg != val)
>>> Â Â Â Â Â Â Â|| !operand_equal_p (arg, val, 0))
>>> Â Â break;
>>
>>> that should fix it.
>>
>> Good idea.
>> Here's what I'm testing now.
> Ok if it passes testing.
Thanks, but arg could be NULL, and then TREE_CODE (val) would crash.
The fixed patch below corrects the two regressions I got testing the
patch on x86_64-linux-gnu. Save for new regressions, I'll check in the
revised version as soon as my current round of testing completes.
for gcc/ChangeLog
from Alexandre Oliva <aoliva@redhat.com>
* tree-ssa.c (find_released_ssa_name): Handle NULL wi.
(insert_debug_temp_for_var_def): Handle degenerate PHI nodes.
(insert_debug_temps_for_defs): Handle PHI nodes.
* tree-ssa-dom.c (degenerate_phi_result): Don't crash on released
SSA names.
Index: gcc/tree-ssa.c
===================================================================
--- gcc/tree-ssa.c.orig 2009-11-19 05:12:30.000000000 -0200
+++ gcc/tree-ssa.c 2009-11-19 05:12:35.000000000 -0200
@@ -279,7 +279,7 @@ find_released_ssa_name (tree *tp, int *w
{
struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
- if (wi->is_lhs)
+ if (wi && wi->is_lhs)
return NULL_TREE;
if (TREE_CODE (*tp) == SSA_NAME)
@@ -346,7 +346,13 @@ insert_debug_temp_for_var_def (gimple_st
/* If we didn't get an insertion point, and the stmt has already
been removed, we won't be able to insert the debug bind stmt, so
we'll have to drop debug information. */
- if (is_gimple_assign (def_stmt))
+ if (gimple_code (def_stmt) == GIMPLE_PHI)
+ {
+ value = degenerate_phi_result (def_stmt);
+ if (value && walk_tree (&value, find_released_ssa_name, NULL, NULL))
+ value = NULL;
+ }
+ else if (is_gimple_assign (def_stmt))
{
bool no_value = false;
@@ -408,6 +414,7 @@ insert_debug_temp_for_var_def (gimple_st
at the expense of duplication of expressions. */
if (CONSTANT_CLASS_P (value)
+ || gimple_code (def_stmt) == GIMPLE_PHI
|| (usecount == 1
&& (!gimple_assign_single_p (def_stmt)
|| is_gimple_min_invariant (value)))
@@ -478,7 +485,7 @@ insert_debug_temps_for_defs (gimple_stmt
stmt = gsi_stmt (*gsi);
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, op_iter, SSA_OP_DEF)
+ FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
{
tree var = DEF_FROM_PTR (def_p);
Index: gcc/tree-ssa-dom.c
===================================================================
--- gcc/tree-ssa-dom.c.orig 2009-11-19 05:12:30.000000000 -0200
+++ gcc/tree-ssa-dom.c 2009-11-20 04:30:10.000000000 -0200
@@ -2398,7 +2398,14 @@ degenerate_phi_result (gimple phi)
continue;
else if (!val)
val = arg;
- else if (!operand_equal_p (arg, val, 0))
+ else if (arg == val)
+ continue;
+ /* We bring in some of operand_equal_p not only to speed things
+ up, but also to avoid crashing when dereferencing the type of
+ a released SSA name. */
+ else if (!arg || TREE_CODE (val) != TREE_CODE (arg)
+ || TREE_CODE (val) == SSA_NAME
+ || !operand_equal_p (arg, val, 0))
break;
}
return (i == gimple_phi_num_args (phi) ? val : NULL);
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist Red Hat Brazil Compiler Engineer