When loop distribution releases a PHI node of the original IL it
can end up clobbering memory that's re-used when it upon releasing
its RDG resets all stmt UIDs back to -1, even those that got released.
The fix is to avoid resetting UIDs based on stmts in the RDG but
instead reset only those still present in the loop.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
PR tree-optimization/114998
* tree-loop-distribution.cc (free_rdg): Take loop argument.
Reset UIDs of stmts still in the IL rather than all stmts
referenced from the RDG.
(loop_distribution::build_rdg): Pass loop to free_rdg.
(loop_distribution::distribute_loop): Likewise.
(loop_distribution::transform_reduction_loop): Likewise.
* gcc.dg/torture/pr114998.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr114998.c | 35 +++++++++++++++++++++++++
gcc/tree-loop-distribution.cc | 24 ++++++++++++-----
2 files changed, 53 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr114998.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr114998.c
b/gcc/testsuite/gcc.dg/torture/pr114998.c
new file mode 100644
index 00000000000..81fc1e077cb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr114998.c
@@ -0,0 +1,35 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fno-tree-dce -ftree-loop-distribution" } */
+
+short a, d;
+int b, c, f, g, h, i, j[2], o;
+__attribute__((const)) int s(char r);
+int main() {
+ int l, m, k, n;
+ if (b) {
+ char p;
+ for (; p >= 0; p--) {
+ int e[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0,
+ 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1,
+ 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0};
+ if (j[p]) {
+ int q[1];
+ i = o;
+ o = q[h];
+ if (g)
+ n = d;
+ m = 4;
+ for (; m; m--) {
+ if (l)
+ k |= c;
+ if (a)
+ break;
+ }
+ }
+ s(n);
+ f |= b;
+ }
+ }
+ return 0;
+}
diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc
index 95203fefa18..45932bae5e7 100644
--- a/gcc/tree-loop-distribution.cc
+++ b/gcc/tree-loop-distribution.cc
@@ -778,7 +778,7 @@ loop_distribution::stmts_from_loop (class loop *loop,
vec<gimple *> *stmts)
/* Free the reduced dependence graph RDG. */
static void
-free_rdg (struct graph *rdg)
+free_rdg (struct graph *rdg, loop_p loop)
{
int i;
@@ -792,13 +792,25 @@ free_rdg (struct graph *rdg)
if (v->data)
{
- gimple_set_uid (RDGV_STMT (v), -1);
(RDGV_DATAREFS (v)).release ();
free (v->data);
}
}
free_graph (rdg);
+
+ /* Reset UIDs of stmts still in the loop. */
+ basic_block *bbs = get_loop_body (loop);
+ for (unsigned i = 0; i < loop->num_nodes; ++i)
+ {
+ basic_block bb = bbs[i];
+ gimple_stmt_iterator gsi;
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ gimple_set_uid (gsi_stmt (gsi), -1);
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ gimple_set_uid (gsi_stmt (gsi), -1);
+ }
+ free (bbs);
}
struct graph *
@@ -812,7 +824,7 @@ loop_distribution::build_rdg (class loop *loop,
control_dependences *cd)
rdg = new_graph (stmts.length ());
if (!create_rdg_vertices (rdg, stmts, loop))
{
- free_rdg (rdg);
+ free_rdg (rdg, loop);
return NULL;
}
stmts.release ();
@@ -3062,7 +3074,7 @@ loop_distribution::distribute_loop (class loop *loop,
"Loop %d not distributed: too many memory references.\n",
loop->num);
- free_rdg (rdg);
+ free_rdg (rdg, loop);
loop_nest.release ();
free_data_refs (datarefs_vec);
delete ddrs_table;
@@ -3259,7 +3271,7 @@ loop_distribution::distribute_loop (class loop *loop,
FOR_EACH_VEC_ELT (partitions, i, partition)
partition_free (partition);
- free_rdg (rdg);
+ free_rdg (rdg, loop);
return nbp - *nb_calls;
}
@@ -3665,7 +3677,7 @@ loop_distribution::transform_reduction_loop (loop_p loop)
auto_bitmap partition_stmts;
bitmap_set_range (partition_stmts, 0, rdg->n_vertices);
find_single_drs (loop, rdg, partition_stmts, &store_dr, &load_dr);
- free_rdg (rdg);
+ free_rdg (rdg, loop);
/* Bail out if there is no single load. */
if (load_dr == NULL)
--
2.35.3
