[committed] openmp: Avoid ICEs due to orphaned labels in OpenMP regions [PR99322]
Jakub Jelinek
jakub@redhat.com
Fri Mar 5 21:00:27 GMT 2021
Hi!
When performing cfg cleanup at the end of cfg pass, if there are any OpenMP
regions and some basic blocks are unreachable and contain forced labels,
remove_bb moves the labels to previous bb, but if the two bb belong to different
OpenMP regions, that means it will end up in a different function from where
it was assumed to be and checked e.g. during gimplification or OpenMP region
SESE checking.
The following patch will place the labels to some bb from the right OpenMP
region if the previous bb is not that. I think it should happen very rarely,
normally the bbs from each OpenMP region should be from the before-cfg pass
adjacent and the problems will usually be only if the OpenMP regions are
no-return, so I hope it isn't fatal that it searches through all bbs on the miss.
If it turns out to be a problem, it can always lazily create some better data
structure and maintain it through bb removals when it reaches that case the
first time.
Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.
2021-03-05 Jakub Jelinek <jakub@redhat.com>
PR middle-end/99322
* tree-cfg.c (bb_to_omp_idx): New variable.
(execute_build_cfg): Release the bb_to_omp_idx vector after
cleanup_tree_cfg returns.
(handle_abnormal_edges): Remove bb_to_omp_idx argument, adjust
for bb_to_omp_idx being a vec<int> instead of pointer to array
of ints.
(make_edges): Remove bb_to_omp_idx local variable, don't pass
it to handle_abnormal_edges, adjust for bb_to_omp_idx being a
vec<int> instead of pointer to array of ints and don't free/release
it at the end.
(remove_bb): When removing a bb and placing forced label somewhere
else, ensure it is put into the same OpenMP region during cfg
pass if possible or to entry successor as fallback. Unregister
bb from bb_to_omp_idx.
* c-c++-common/gomp/pr99322.c: New test.
--- gcc/tree-cfg.c.jj 2021-02-19 12:14:31.616880014 +0100
+++ gcc/tree-cfg.c 2021-03-05 17:38:23.639195846 +0100
@@ -93,6 +93,9 @@ static hash_map<edge, tree> *edge_to_cas
static bitmap touched_switch_bbs;
+/* OpenMP region idxs for blocks during cfg pass. */
+static vec<int> bb_to_omp_idx;
+
/* CFG statistics. */
struct cfg_stats_d
{
@@ -372,6 +375,9 @@ execute_build_cfg (void)
dump_scope_blocks (dump_file, dump_flags);
}
cleanup_tree_cfg ();
+
+ bb_to_omp_idx.release ();
+
loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
replace_loop_annotate ();
return 0;
@@ -724,8 +730,7 @@ get_abnormal_succ_dispatcher (basic_bloc
if COMPUTED_GOTO is false, otherwise factor the computed gotos. */
static void
-handle_abnormal_edges (basic_block *dispatcher_bbs,
- basic_block for_bb, int *bb_to_omp_idx,
+handle_abnormal_edges (basic_block *dispatcher_bbs, basic_block for_bb,
auto_vec<basic_block> *bbs, bool computed_goto)
{
basic_block *dispatcher = dispatcher_bbs + (computed_goto ? 1 : 0);
@@ -733,7 +738,7 @@ handle_abnormal_edges (basic_block *disp
basic_block bb;
bool inner = false;
- if (bb_to_omp_idx)
+ if (!bb_to_omp_idx.is_empty ())
{
dispatcher = dispatcher_bbs + 2 * bb_to_omp_idx[for_bb->index];
if (bb_to_omp_idx[for_bb->index] != 0)
@@ -748,7 +753,7 @@ handle_abnormal_edges (basic_block *disp
/* Check if there are any basic blocks that need to have
abnormal edges to this dispatcher. If there are none, return
early. */
- if (bb_to_omp_idx == NULL)
+ if (bb_to_omp_idx.is_empty ())
{
if (bbs->is_empty ())
return;
@@ -790,7 +795,7 @@ handle_abnormal_edges (basic_block *disp
FOR_EACH_VEC_ELT (*bbs, idx, bb)
{
- if (bb_to_omp_idx
+ if (!bb_to_omp_idx.is_empty ()
&& bb_to_omp_idx[bb->index] != bb_to_omp_idx[for_bb->index])
continue;
@@ -820,7 +825,7 @@ handle_abnormal_edges (basic_block *disp
/* Create predecessor edges of the dispatcher. */
FOR_EACH_VEC_ELT (*bbs, idx, bb)
{
- if (bb_to_omp_idx
+ if (!bb_to_omp_idx.is_empty ()
&& bb_to_omp_idx[bb->index] != bb_to_omp_idx[for_bb->index])
continue;
make_edge (bb, *dispatcher, EDGE_ABNORMAL);
@@ -957,7 +962,6 @@ make_edges (void)
struct omp_region *cur_region = NULL;
auto_vec<basic_block> ab_edge_goto;
auto_vec<basic_block> ab_edge_call;
- int *bb_to_omp_idx = NULL;
int cur_omp_region_idx = 0;
/* Create an edge from entry to the first block with executable
@@ -971,7 +975,7 @@ make_edges (void)
{
int mer;
- if (bb_to_omp_idx)
+ if (!bb_to_omp_idx.is_empty ())
bb_to_omp_idx[bb->index] = cur_omp_region_idx;
mer = make_edges_bb (bb, &cur_region, &cur_omp_region_idx);
@@ -980,8 +984,8 @@ make_edges (void)
else if (mer == 2)
ab_edge_call.safe_push (bb);
- if (cur_region && bb_to_omp_idx == NULL)
- bb_to_omp_idx = XCNEWVEC (int, n_basic_blocks_for_fn (cfun));
+ if (cur_region && bb_to_omp_idx.is_empty ())
+ bb_to_omp_idx.safe_grow_cleared (n_basic_blocks_for_fn (cfun), true);
}
/* Computed gotos are hell to deal with, especially if there are
@@ -1006,7 +1010,7 @@ make_edges (void)
basic_block *dispatcher_bbs = dispatcher_bb_array;
int count = n_basic_blocks_for_fn (cfun);
- if (bb_to_omp_idx)
+ if (!bb_to_omp_idx.is_empty ())
dispatcher_bbs = XCNEWVEC (basic_block, 2 * count);
FOR_EACH_BB_FN (bb, cfun)
@@ -1024,12 +1028,12 @@ make_edges (void)
/* Make an edge to every label block that has been marked as a
potential target for a computed goto or a non-local goto. */
if (FORCED_LABEL (target))
- handle_abnormal_edges (dispatcher_bbs, bb, bb_to_omp_idx,
- &ab_edge_goto, true);
+ handle_abnormal_edges (dispatcher_bbs, bb, &ab_edge_goto,
+ true);
if (DECL_NONLOCAL (target))
{
- handle_abnormal_edges (dispatcher_bbs, bb, bb_to_omp_idx,
- &ab_edge_call, false);
+ handle_abnormal_edges (dispatcher_bbs, bb, &ab_edge_call,
+ false);
break;
}
}
@@ -1044,17 +1048,15 @@ make_edges (void)
&& ((gimple_call_flags (call_stmt) & ECF_RETURNS_TWICE)
|| gimple_call_builtin_p (call_stmt,
BUILT_IN_SETJMP_RECEIVER)))
- handle_abnormal_edges (dispatcher_bbs, bb, bb_to_omp_idx,
- &ab_edge_call, false);
+ handle_abnormal_edges (dispatcher_bbs, bb, &ab_edge_call,
+ false);
}
}
- if (bb_to_omp_idx)
+ if (!bb_to_omp_idx.is_empty ())
XDELETE (dispatcher_bbs);
}
- XDELETE (bb_to_omp_idx);
-
omp_free_regions ();
}
@@ -2301,6 +2303,30 @@ remove_bb (basic_block bb)
new_bb = single_succ (new_bb);
gcc_assert (new_bb != bb);
}
+ if ((unsigned) bb->index < bb_to_omp_idx.length ()
+ && ((unsigned) new_bb->index >= bb_to_omp_idx.length ()
+ || (bb_to_omp_idx[bb->index]
+ != bb_to_omp_idx[new_bb->index])))
+ {
+ /* During cfg pass make sure to put orphaned labels
+ into the right OMP region. */
+ unsigned int i;
+ int idx;
+ new_bb = NULL;
+ FOR_EACH_VEC_ELT (bb_to_omp_idx, i, idx)
+ if (i >= NUM_FIXED_BLOCKS
+ && idx == bb_to_omp_idx[bb->index]
+ && i != (unsigned) bb->index)
+ {
+ new_bb = BASIC_BLOCK_FOR_FN (cfun, i);
+ break;
+ }
+ if (new_bb == NULL)
+ {
+ new_bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+ gcc_assert (new_bb != bb);
+ }
+ }
new_gsi = gsi_after_labels (new_bb);
gsi_remove (&i, false);
gsi_insert_before (&new_gsi, stmt, GSI_NEW_STMT);
@@ -2319,6 +2345,8 @@ remove_bb (basic_block bb)
}
}
+ if ((unsigned) bb->index < bb_to_omp_idx.length ())
+ bb_to_omp_idx[bb->index] = -1;
remove_phi_nodes_and_edges_for_unreachable_block (bb);
bb->il.gimple.seq = NULL;
bb->il.gimple.phi_nodes = NULL;
--- gcc/testsuite/c-c++-common/gomp/pr99322.c.jj 2021-03-05 17:42:12.869659324 +0100
+++ gcc/testsuite/c-c++-common/gomp/pr99322.c 2021-03-05 17:42:01.785781961 +0100
@@ -0,0 +1,26 @@
+/* PR middle-end/99322 */
+/* { dg-do compile } */
+
+void foo (void);
+void qux (void *);
+
+void
+bar (void)
+{
+ #pragma omp parallel
+ for (;;)
+ for (int i = 0; i < 8; ++i)
+ foo ();
+ { lab:; }
+ qux (&&lab);
+}
+
+void
+baz (void)
+{
+ qux (&&lab);
+ #pragma omp parallel
+ for (;;)
+ ;
+ lab:;
+}
Jakub
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