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[PATCH] Do not allow irreducible loops/regions in a scop
- From: Aditya Kumar <aditya dot k7 at samsung dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: tobias at grosser dot es, richard dot guenther at gmail dot com, aditya dot k7 at samsung dot com, s dot pop at samsung dot com, sebpop at gmail dot com, a dot zaafrani at samsung dot com
- Date: Fri, 6 Nov 2015 11:43:45 -0600
- Subject: [PATCH] Do not allow irreducible loops/regions in a scop
- Authentication-results: sourceware.org; auth=none
Irreducible regions are not going to be optimized by ISL
so discard them early. Passes bootstrap and regtest.
gcc/ChangeLog:
2015-11-06 Aditya Kumar <aditya.k7@samsung.com>
* graphite-scop-detection.c (scop_detection::merge_sese): Entry and exit edges should not be a part of irreducible loop.
(scop_detection::can_represent_loop_1): Loops should not be irreducible.
(scop_detection::harmful_stmt_in_region): All the basic block should belong to reducible loops.
---
gcc/graphite-scop-detection.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/gcc/graphite-scop-detection.c b/gcc/graphite-scop-detection.c
index ae8497d..b1f2ebc 100644
--- a/gcc/graphite-scop-detection.c
+++ b/gcc/graphite-scop-detection.c
@@ -794,7 +794,8 @@ scop_detection::merge_sese (sese_l first, sese_l second) const
get_entry_bb (second));
edge entry = get_nearest_dom_with_single_entry (dom);
- if (!entry)
+
+ if (!entry || (entry->flags & EDGE_IRREDUCIBLE_LOOP))
return invalid_sese;
basic_block pdom = nearest_common_dominator (CDI_POST_DOMINATORS,
@@ -803,7 +804,8 @@ scop_detection::merge_sese (sese_l first, sese_l second) const
pdom = nearest_common_dominator (CDI_POST_DOMINATORS, dom, pdom);
edge exit = get_nearest_pdom_with_single_exit (pdom);
- if (!exit)
+
+ if (!exit || (exit->flags & EDGE_IRREDUCIBLE_LOOP))
return invalid_sese;
sese_l combined (entry, exit);
@@ -923,6 +925,7 @@ scop_detection::can_represent_loop_1 (loop_p loop, sese_l scop)
struct tree_niter_desc niter_desc;
return single_exit (loop)
+ && !(loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)
&& number_of_iterations_exit (loop, single_exit (loop), &niter_desc, false)
&& niter_desc.control.no_overflow
&& (niter = number_of_latch_executions (loop))
@@ -1053,6 +1056,10 @@ scop_detection::harmful_stmt_in_region (sese_l scop) const
if (!dominated_by_p (CDI_POST_DOMINATORS, bb, exit_bb))
continue;
+ /* The basic block should not be part of an irreducible loop. */
+ if (bb->flags & BB_IRREDUCIBLE_LOOP)
+ return true;
+
if (harmful_stmt_in_bb (scop, bb))
return true;
}
--
2.1.0.243.g30d45f7