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[PR65637][PATCH][1/3] Fix gcc_assert in expand_omp_for_static_chunk
- From: Tom de Vries <Tom_deVries at mentor dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 15 Apr 2015 15:15:20 +0200
- Subject: [PR65637][PATCH][1/3] Fix gcc_assert in expand_omp_for_static_chunk
- Authentication-results: sourceware.org; auth=none
- References: <552E6341 dot 4040401 at mentor dot com>
On 15-04-15 15:10, Tom de Vries wrote:
Hi,
This patch series fixes PR65637.
Currently, ssa-handling code in expand_omp_for_static_chunk is dead and not
exercised by testing.
Ssa-handling code in omp-low.c is only triggered by pass_parallelize_loops, and
that pass doesn't specify a chunk size on the GIMPLE_OMP_FOR it constructs, so
that only exercises the expand_omp_for_static_nochunk path.
Using the attached trigger patch, we excercise the ssa-handling code in
expand_omp_for_static_chunk. The following patch series fixes the problems in
the ssa-handling code that we encounter.
1. Fix gcc_assert in expand_omp_for_static_chunk
2. Fix inner loop phi in expand_omp_for_static_chunk
3. Handle 2 preds for fin_bb in expand_omp_for_static_chunk
The patch series has been bootstrapped and reg-tested on x86_64 together with
attached trigger patch.
I'll post the patches from the patch series individually, in response to this
email.
This patch fixes a segfault in an gcc_assert in expand_omp_for_static_chunk
while compiling autopar/pr46099.c.
When compiling f1 from autopar/pr46099.c using expand_omp_for_static_chunk, we
redirect the edge (trip_update_bb -> fin_bb) to point to iter_part_bb:
...
redirect_edge_and_branch (single_succ_edge (trip_update_bb), iter_part_bb);
...
And fin_bb is an empty block without any phis, so during the redirect we don't
store any entries in the edge_var_map:
...
(gdb) call debug_bb (fin_bb)
;; basic block 18, loop depth 0, count 0, freq 0, maybe hot
;; prev block 21, next block 16, flags: (NEW)
;; pred: 21 [100.0%] (FALLTHRU)
;; 19 (FALSE_VALUE)
;; succ: 16 [100.0%] (FALLTHRU)
...
Consequently, head will be NULL.
...
vec<edge_var_map> *head = redirect_edge_var_map_vector (re);
...
And because head is NULL, this assert causes a segfault:
...
gcc_assert (gsi_end_p (psi) && i == head->length ());
...
This patch fixes that, by handling the case that head is NULL in the assert.
OK for trunk?
Thanks,
- Tom
Fix gcc_assert in expand_omp_for_static_chunk
2015-04-15 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/65637
* omp-low.c (expand_omp_for_static_chunk): Fix gcc_assert for the case
that head is NULL.
---
gcc/omp-low.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 80bddf0..f7b9d11 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -7274,7 +7274,7 @@ expand_omp_for_static_chunk (struct omp_region *region,
locus = redirect_edge_var_map_location (vm);
add_phi_arg (nphi, redirect_edge_var_map_def (vm), re, locus);
}
- gcc_assert (gsi_end_p (psi) && i == head->length ());
+ gcc_assert (gsi_end_p (psi) && (head == NULL || i == head->length ()));
redirect_edge_var_map_clear (re);
while (1)
{
--
1.9.1