The following works around the issue that PRE inserts expressions into
the VN hashes without having a representative for them. First the
patch avoids inserting fully constant expressions and second it deals
with the above by assigning a representative once VN insertion needs one.
The way PRE uses the VN hashes here probably needs some (big) overhaul
but the following should get us past the failure point in a reasonable
way as well.
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Richard.
2016-05-11 Richard Biener <rguent...@suse.de>
PR tree-optimization/71059
* tree-ssa-pre.c (phi_translate_1): Fully fold translated
nary before looking up or entering the expression into the VN
hashes.
* tree-ssa-sccvn.c (vn_nary_build_or_lookup): Fix comment typo.
Make sure to re-use NARYs without result as inserted by
phi-translation.
* gcc.dg/torture/pr71059.c: New testcase.
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c (revision 236069)
--- gcc/tree-ssa-pre.c (working copy)
*************** phi_translate_1 (pre_expr expr, bitmap_s
*** 1464,1469 ****
--- 1464,1475 ----
pre_expr constant;
unsigned int new_val_id;
+ PRE_EXPR_NARY (expr) = newnary;
+ constant = fully_constant_expression (expr);
+ PRE_EXPR_NARY (expr) = nary;
+ if (constant != expr)
+ return constant;
+
tree result = vn_nary_op_lookup_pieces (newnary->length,
newnary->opcode,
newnary->type,
*************** phi_translate_1 (pre_expr expr, bitmap_s
*** 1478,1487 ****
if (nary)
{
PRE_EXPR_NARY (expr) = nary;
- constant = fully_constant_expression (expr);
- if (constant != expr)
- return constant;
-
new_val_id = nary->value_id;
get_or_alloc_expression_id (expr);
}
--- 1484,1489 ----
*************** phi_translate_1 (pre_expr expr, bitmap_s
*** 1495,1503 ****
&newnary->op[0],
result, new_val_id);
PRE_EXPR_NARY (expr) = nary;
- constant = fully_constant_expression (expr);
- if (constant != expr)
- return constant;
get_or_alloc_expression_id (expr);
}
add_to_value (new_val_id, expr);
--- 1497,1502 ----
Index: gcc/testsuite/gcc.dg/torture/pr71059.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr71059.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr71059.c (working copy)
***************
*** 0 ****
--- 1,15 ----
+ /* { dg-do compile } */
+
+ short a, c;
+ union {
+ unsigned f0;
+ unsigned short f1;
+ } b;
+ volatile int d;
+ short fn1(short p1) { return p1 + a; }
+ void fn2()
+ {
+ b.f0 = 0;
+ for (;; b.f0 = fn1(b.f0))
+ (c && b.f1) || d;
+ }
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c (revision 236159)
--- gcc/tree-ssa-sccvn.c (working copy)
*************** vn_nary_build_or_lookup (code_helper rco
*** 1632,1638 ****
{
tree result = NULL_TREE;
/* We will be creating a value number for
! ROCDE (OPS...).
So first simplify and lookup this expression to see if it
is already available. */
mprts_hook = vn_lookup_simplify_result;
--- 1632,1638 ----
{
tree result = NULL_TREE;
/* We will be creating a value number for
! RCODE (OPS...).
So first simplify and lookup this expression to see if it
is already available. */
mprts_hook = vn_lookup_simplify_result;
*************** vn_nary_build_or_lookup (code_helper rco
*** 1682,1687 ****
--- 1682,1697 ----
gimple_seq_add_stmt_without_update (&VN_INFO (result)->expr,
new_stmt);
VN_INFO (result)->needs_insertion = true;
+ /* ??? PRE phi-translation inserts NARYs without corresponding
+ SSA name result. Re-use those but set their result according
+ to the stmt we just built. */
+ vn_nary_op_t nary = NULL;
+ vn_nary_op_lookup_stmt (new_stmt, &nary);
+ if (nary)
+ {
+ gcc_assert (nary->result == NULL_TREE);
+ nary->result = gimple_assign_lhs (new_stmt);
+ }
/* As all "inserted" statements are singleton SCCs, insert
to the valid table. This is strictly needed to
avoid re-generating new value SSA_NAMEs for the same
*************** vn_nary_build_or_lookup (code_helper rco
*** 1689,1695 ****
optimistic table gets cleared after each iteration).
We do not need to insert into the optimistic table, as
lookups there will fall back to the valid table. */
! if (current_info == optimistic_info)
{
current_info = valid_info;
vn_nary_op_insert_stmt (new_stmt, result);
--- 1699,1705 ----
optimistic table gets cleared after each iteration).
We do not need to insert into the optimistic table, as
lookups there will fall back to the valid table. */
! else if (current_info == optimistic_info)
{
current_info = valid_info;
vn_nary_op_insert_stmt (new_stmt, result);
