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re PR middle-end/46761 (-fgraphite-identity produces wrong code for array initialization arr[i] = i)

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PR middle-end/46761
	* graphite-clast-to-gimple.c (graphite_create_new_loop_guard): Prefer
	to use unadjusted UB.

testsuite:
	* gcc.dg/graphite/pr46761.c: New.

From-SVN: r167980
This commit is contained in:
Alexander Monakov 2010-12-17 15:54:59 +03:00 • committed by Alexander Monakov
parent 7ca1703338
commit 8b432c8b83
4 changed files with 49 additions and 12 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2010-12-17 Alexander Monakov <amonakov@ispras.ru>
PR middle-end/46761
* graphite-clast-to-gimple.c (graphite_create_new_loop_guard): Prefer
to use unadjusted UB.
2010-12-17 Dodji Seketeli <dodji@redhat.com>
* dwarf2out.c (gen_type_die_with_usage): Do not try to emit debug

28
gcc/graphite-clast-to-gimple.c
View file

@ -975,20 +975,24 @@ graphite_create_new_loop_guard (sese region, edge entry_edge,
newivs_index, params_index);
tree ub = clast_to_gcc_expression (type, stmt->UB, region, newivs,
newivs_index, params_index);
tree one = POINTER_TYPE_P (type) ? size_one_node
: fold_convert (type, integer_one_node);
/* Adding +1 and using LT_EXPR helps with loop latches that have a
loop iteration count of "PARAMETER - 1". For PARAMETER == 0 this becomes
2^{32|64}, and the condition lb <= ub is true, even if we do not want this.
However lb < ub + 1 is false, as expected. */
tree ub_one = fold_build2 (POINTER_TYPE_P (type) ? POINTER_PLUS_EXPR
: PLUS_EXPR, type, ub, one);
/* When ub + 1 wraps around, use lb <= ub. */
if (integer_zerop (ub_one))
/* When ub is simply a constant or a parameter, use lb <= ub. */
if (TREE_CODE (ub) == INTEGER_CST || TREE_CODE (ub) == SSA_NAME)
cond_expr = fold_build2 (LE_EXPR, boolean_type_node, lb, ub);
else
cond_expr = fold_build2 (LT_EXPR, boolean_type_node, lb, ub_one);
{
tree one = (POINTER_TYPE_P (type)
? size_one_node
: fold_convert (type, integer_one_node));
/* Adding +1 and using LT_EXPR helps with loop latches that have a
loop iteration count of "PARAMETER - 1". For PARAMETER == 0 this becomes
2^k-1 due to integer overflow, and the condition lb <= ub is true,
even if we do not want this. However lb < ub + 1 is false, as
expected. */
tree ub_one = fold_build2 (POINTER_TYPE_P (type) ? POINTER_PLUS_EXPR
: PLUS_EXPR, type, ub, one);
cond_expr = fold_build2 (LT_EXPR, boolean_type_node, lb, ub_one);
}
exit_edge = create_empty_if_region_on_edge (entry_edge, cond_expr);

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2010-12-17 Alexander Monakov <amonakov@ispras.ru>
PR middle-end/46761
* gcc.dg/graphite/pr46761.c: New.
2010-12-17 Janus Weil <janus@gcc.gnu.org>
PR fortran/46849

22
gcc/testsuite/gcc.dg/graphite/pr46761.c Normal file
View file

@ -0,0 +1,22 @@
/* { dg-do run } */
/* { dg-options "-O -fgraphite-identity" } */
#define N 128
int
main ()
{
int arr[N], i, s = 0;
for (i = 0; i < N; i++)
arr[i] = i;
for (i = 0; i < N; i++)
if (arr[i] != i)
__builtin_abort ();
for (i = 0; i < N; i++)
s += arr[i];
if (s != (N * (N - 1)) / 2)
__builtin_abort ();
return 0;
}