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Re: [PATCH] Fix PR38926, ICE in PRE
On Tue, 27 Jan 2009, Richard Guenther wrote:
>
> It happens that during insertion we insert a PHI node which looks the
> same like an existing PHI node but we insert it for a different
> value-number. In this case we may not add the PHI node as expression
> to that value-number.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, Danny, does this
> look ok or do you want to track down why we have this mismatched
> value-numbers in the first place? (looks like a missed optimization to
> me)
On a second thought that whole code is bogus (I added it last year).
So I have bootstrapped and tested the following instead.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2009-01-27 Richard Guenther <rguenther@suse.de>
PR tree-optimization/38926
* tree-ssa-pre.c (add_to_value): Assert we add only expressions
with the correct value id to a value.
(do_regular_insertion): Use the value number of edoubleprime
for the value number of the expr.
Revert
2008-08-21 Richard Guenther <rguenther@suse.de>
* tree-ssa-pre.c (insert_into_preds_of_block): Before inserting
a PHI ask VN if it is already available.
* tree-ssa-sccvn.h (vn_phi_lookup): Declare.
* tree-ssa-sccvn.c (vn_phi_lookup): Export.
* gcc.c-torture/compile/pr38926.c: New testcase.
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c (revision 143699)
--- gcc/tree-ssa-pre.c (working copy)
*************** phi_trans_add (pre_expr e, pre_expr v, b
*** 552,557 ****
--- 552,560 ----
}
+ static unsigned int
+ get_expr_value_id (pre_expr);
+
/* Add expression E to the expression set of value id V. */
void
*************** add_to_value (unsigned int v, pre_expr e
*** 559,564 ****
--- 562,569 ----
{
bitmap_set_t set;
+ gcc_assert (get_expr_value_id (e) == v);
+
if (v >= VEC_length (bitmap_set_t, value_expressions))
{
VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
*************** do_regular_insertion (basic_block block,
*** 3330,3336 ****
pre_stats.constified++;
}
else
! info->valnum = PRE_EXPR_NAME (edoubleprime);
info->value_id = new_val;
}
}
--- 3340,3346 ----
pre_stats.constified++;
}
else
! info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
info->value_id = new_val;
}
}
Index: gcc/testsuite/gcc.c-torture/compile/pr38926.c
===================================================================
*** gcc/testsuite/gcc.c-torture/compile/pr38926.c (revision 0)
--- gcc/testsuite/gcc.c-torture/compile/pr38926.c (revision 0)
***************
*** 0 ****
--- 1,41 ----
+ static inline int foo (unsigned _si1)
+ {
+ if (_si1 != 0)
+ if (_si1 > 2147483647)
+ return 1;
+ return 0;
+ }
+
+ static inline unsigned bar (unsigned _left, int _right)
+ {
+ return (unsigned) _right >= 8 ? 1 : _left >> _right;
+ }
+
+ unsigned g_2;
+ unsigned g_67;
+ volatile unsigned g_162;
+
+ static inline int func_62 (unsigned p_63)
+ {
+ p_63 = g_2 & g_67;
+ if (g_2)
+ ;
+ else if (p_63)
+ return 1;
+ g_67 = bar (p_63, g_2);
+ return 0;
+ }
+
+ unsigned baz (void)
+ {
+ if (g_2)
+ for (; g_2 <= -16; g_2 = foo (g_2))
+ {
+ for (; g_162; g_162)
+ func_62 (func_62 (0));
+ if (g_67)
+ break;
+ }
+ return g_2;
+ }
+
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c (revision 143721)
--- gcc/tree-ssa-sccvn.c (working copy)
*************** static VEC(tree, heap) *shared_lookup_ph
*** 1481,1487 ****
value number if it exists in the hash table. Return NULL_TREE if
it does not exist in the hash table. */
! tree
vn_phi_lookup (gimple phi)
{
void **slot;
--- 1481,1487 ----
value number if it exists in the hash table. Return NULL_TREE if
it does not exist in the hash table. */
! static tree
vn_phi_lookup (gimple phi)
{
void **slot;
Index: gcc/tree-ssa-sccvn.h
===================================================================
*** gcc/tree-ssa-sccvn.h (revision 143721)
--- gcc/tree-ssa-sccvn.h (working copy)
*************** vn_reference_t vn_reference_insert (tree
*** 184,190 ****
vn_reference_t vn_reference_insert_pieces (VEC (tree, gc) *,
VEC (vn_reference_op_s, heap) *,
tree, unsigned int);
- tree vn_phi_lookup (gimple);
hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
int vn_nary_op_eq (const void *, const void *);
--- 184,189 ----
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c (revision 143721)
--- gcc/tree-ssa-pre.c (working copy)
*************** insert_into_preds_of_block (basic_block
*** 2975,2981 ****
pre_expr eprime;
edge_iterator ei;
tree type = get_expr_type (expr);
! tree temp, res;
gimple phi;
if (dump_file && (dump_flags & TDF_DETAILS))
--- 2975,2981 ----
pre_expr eprime;
edge_iterator ei;
tree type = get_expr_type (expr);
! tree temp;
gimple phi;
if (dump_file && (dump_flags & TDF_DETAILS))
*************** insert_into_preds_of_block (basic_block
*** 3131,3138 ****
if (TREE_CODE (type) == COMPLEX_TYPE
|| TREE_CODE (type) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (temp) = 1;
-
phi = create_phi_node (temp, block);
FOR_EACH_EDGE (pred, ei, block->preds)
{
pre_expr ae = avail[pred->src->index];
--- 3131,3142 ----
if (TREE_CODE (type) == COMPLEX_TYPE
|| TREE_CODE (type) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (temp) = 1;
phi = create_phi_node (temp, block);
+
+ gimple_set_plf (phi, NECESSARY, false);
+ VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
+ VN_INFO (gimple_phi_result (phi))->value_id = val;
+ VEC_safe_push (gimple, heap, inserted_exprs, phi);
FOR_EACH_EDGE (pred, ei, block->preds)
{
pre_expr ae = avail[pred->src->index];
*************** insert_into_preds_of_block (basic_block
*** 3143,3162 ****
else
add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred);
}
- /* If the PHI node is already available, use it. */
- if ((res = vn_phi_lookup (phi)) != NULL_TREE)
- {
- gimple_stmt_iterator gsi = gsi_for_stmt (phi);
- remove_phi_node (&gsi, true);
- release_defs (phi);
- add_to_value (val, get_or_alloc_expr_for_name (res));
- return false;
- }
-
- gimple_set_plf (phi, NECESSARY, false);
- VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
- VN_INFO (gimple_phi_result (phi))->value_id = val;
- VEC_safe_push (gimple, heap, inserted_exprs, phi);
newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
add_to_value (val, newphi);
--- 3147,3152 ----