transform_to_exit_first_loop of the parloops pass can appearantly
not handle (certain?) loops that were not header-copied. Thus, better
assert we face a do-while-style loop before parallelizing it.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2012-03-08 Richard Guenther <rguent...@suse.de>
PR tree-optimization/46886
* tree-flow.h (do_while_loop_p): Declare.
* tree-ssa-loop-ch.c (do_while_loop_p): Export.
* tree-parloops.c (parallelize_loops): Only parallelize do-while
loops.
* testsuite/libgomp.c/pr46886.c: New testcase.
Index: gcc/tree-flow.h
===================================================================
*** gcc/tree-flow.h (revision 184007)
--- gcc/tree-flow.h (working copy)
*************** extern bool may_propagate_copy (tree, tr
*** 619,624 ****
--- 619,627 ----
extern bool may_propagate_copy_into_stmt (gimple, tree);
extern bool may_propagate_copy_into_asm (tree);
+ /* In tree-ssa-loop-ch.c */
+ bool do_while_loop_p (struct loop *);
+
/* Affine iv. */
typedef struct
Index: gcc/tree-ssa-loop-ch.c
===================================================================
*** gcc/tree-ssa-loop-ch.c (revision 184007)
--- gcc/tree-ssa-loop-ch.c (working copy)
*************** should_duplicate_loop_header_p (basic_bl
*** 104,110 ****
/* Checks whether LOOP is a do-while style loop. */
! static bool
do_while_loop_p (struct loop *loop)
{
gimple stmt = last_stmt (loop->latch);
--- 104,110 ----
/* Checks whether LOOP is a do-while style loop. */
! bool
do_while_loop_p (struct loop *loop)
{
gimple stmt = last_stmt (loop->latch);
Index: gcc/tree-parloops.c
===================================================================
*** gcc/tree-parloops.c (revision 184007)
--- gcc/tree-parloops.c (working copy)
*************** parallelize_loops (void)
*** 2183,2189 ****
|| loop_has_blocks_with_irreducible_flag (loop)
|| (loop_preheader_edge (loop)->src->flags & BB_IRREDUCIBLE_LOOP)
/* FIXME: the check for vector phi nodes could be removed. */
! || loop_has_vector_phi_nodes (loop))
continue;
estimated = max_stmt_executions_int (loop, false);
/* FIXME: Bypass this check as graphite doesn't update the
--- 2183,2192 ----
|| loop_has_blocks_with_irreducible_flag (loop)
|| (loop_preheader_edge (loop)->src->flags & BB_IRREDUCIBLE_LOOP)
/* FIXME: the check for vector phi nodes could be removed. */
! || loop_has_vector_phi_nodes (loop)
! /* FIXME: transform_to_exit_first_loop does not handle not
! header-copied loops correctly - see PR46886. */
! || !do_while_loop_p (loop))
continue;
estimated = max_stmt_executions_int (loop, false);
/* FIXME: Bypass this check as graphite doesn't update the
Index: libgomp/testsuite/libgomp.c/pr46886.c
===================================================================
*** libgomp/testsuite/libgomp.c/pr46886.c (revision 0)
--- libgomp/testsuite/libgomp.c/pr46886.c (revision 0)
***************
*** 0 ****
--- 1,28 ----
+ /* { dg-do run } */
+ /* { dg-options "-O -ftree-parallelize-loops=4 -fno-tree-ch
-fno-tree-dominator-opts" } */
+
+ void abort(void);
+
+ int d[1024], e[1024];
+
+ int foo (void)
+ {
+ int s = 0;
+ int i;
+ for (i = 0; i < 1024; i++)
+ s += d[i] - e[i];
+ return s;
+ }
+
+ int main ()
+ {
+ int i;
+ for (i = 0; i < 1024; i++)
+ {
+ d[i] = i * 2;
+ e[i] = i;
+ }
+ if (foo () != 1023 * 1024 / 2)
+ abort ();
+ return 0;
+ }
