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| author | Richard Biener <rguenther@suse.de> | 2025-09-08 14:32:38 +0200 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2025-09-08 16:01:22 +0200 |
| commit | 00cd34b1046076a3272f8e8e85c97dc8f4d2ea44 (patch) | |
| tree | 18628b34cb228f0da0914f6bd161e7260e8adfaa /gcc | |
| parent | 2abfcc6cfc9cd82fbbef47f2b03ee7595277023e (diff) | |
| download | gcc-00cd34b1046076a3272f8e8e85c97dc8f4d2ea44.zip gcc-00cd34b1046076a3272f8e8e85c97dc8f4d2ea44.tar.gz gcc-00cd34b1046076a3272f8e8e85c97dc8f4d2ea44.tar.bz2 | |
tree-optimization/121844 - IVOPTs and asm goto in latch
When there's an asm goto in the latch of a loop we may not use
IP_END IVs since instantiating those would (need to) split the
latch edge which in turn invalidates IP_NORMAL position handling.
This is a revision of the PR107997 fix.
PR tree-optimization/107997
PR tree-optimization/121844
* tree-ssa-loop-ivopts.cc (allow_ip_end_pos_p): Do not allow
IP_END for latches ending with a control stmt.
(create_new_iv): Do not split the latch edge, instead assert
that's not necessary.
* gcc.dg/torture/pr121844.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/torture/pr121844.c | 16 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-ivopts.cc | 13 |
2 files changed, 23 insertions, 6 deletions
diff --git a/gcc/testsuite/gcc.dg/torture/pr121844.c b/gcc/testsuite/gcc.dg/torture/pr121844.c new file mode 100644 index 0000000..149d5ea --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr121844.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ + +typedef unsigned long a; +int b[] = {}; +int **c; +short d(a *e, int f) +{ + *c = &f; + for (;;) + asm goto("" : : : : g); + for (; f; f--) { + asm goto("" : : : : g); + g: + *e ^= b[f + 1]; + } +} diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc index 2fe2655..ba727ad 100644 --- a/gcc/tree-ssa-loop-ivopts.cc +++ b/gcc/tree-ssa-loop-ivopts.cc @@ -3200,6 +3200,12 @@ add_candidate_1 (struct ivopts_data *data, tree base, tree step, bool important, static bool allow_ip_end_pos_p (class loop *loop) { + /* Do not allow IP_END when creating the IV would need to split the + latch edge as that makes all IP_NORMAL invalid. */ + auto pos = gsi_last_bb (ip_end_pos (loop)); + if (!gsi_end_p (pos) && stmt_ends_bb_p (*pos)) + return false; + if (!ip_normal_pos (loop)) return true; @@ -7222,12 +7228,7 @@ create_new_iv (struct ivopts_data *data, struct iv_cand *cand) case IP_END: incr_pos = gsi_last_bb (ip_end_pos (data->current_loop)); after = true; - if (!gsi_end_p (incr_pos) && stmt_ends_bb_p (gsi_stmt (incr_pos))) - { - edge e = find_edge (gsi_bb (incr_pos), data->current_loop->header); - incr_pos = gsi_after_labels (split_edge (e)); - after = false; - } + gcc_assert (gsi_end_p (incr_pos) || !stmt_ends_bb_p (*incr_pos)); break; case IP_AFTER_USE: |