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| author | Richard Biener <rguenther@suse.de> | 2022-10-06 11:20:16 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-10-06 12:07:21 +0200 |
| commit | 85333b9265720fc4e49397301cb16324d2b89aa7 (patch) | |
| tree | a0d49cc7eb2e1284a5d04b0b44393cba1aca22ea | |
| parent | 544d14e1b42eeb337fcefb1efe9d108e71a06d52 (diff) | |
| download | gcc-85333b9265720fc4e49397301cb16324d2b89aa7.zip gcc-85333b9265720fc4e49397301cb16324d2b89aa7.tar.gz gcc-85333b9265720fc4e49397301cb16324d2b89aa7.tar.bz2 | |
tree-optimization/107107 - tail-merging VN wrong-code
The following fixes an unintended(?) side-effect of the special
MODIFY_EXPR expression entries we add for tail-merging during VN.
We shouldn't value-number the virtual operand differently here.
PR tree-optimization/107107
* tree-ssa-sccvn.cc (visit_reference_op_store): Do not
affect value-numbering when doing the tail merging
MODIFY_EXPR lookup.
* gcc.dg/pr107107.c: New testcase.
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr107107.c | 25 | ||||
| -rw-r--r-- | gcc/tree-ssa-sccvn.cc | 17 |
2 files changed, 28 insertions, 14 deletions
diff --git a/gcc/testsuite/gcc.dg/pr107107.c b/gcc/testsuite/gcc.dg/pr107107.c new file mode 100644 index 0000000..5ad6a63 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr107107.c @@ -0,0 +1,25 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -ftree-tail-merge" } */ + +static inline void set_longish(int is_long_long, void *p, long x) +{ + if (is_long_long) + *(long long*)p = x; + else + *(long*)p = x; +} +static long test(long long *p, int index, int mode) +{ + *p = 1; + set_longish(mode, p+index, 2); + return *p; +} +long (*volatile vtest)(long long*, int, int) = test; +int main(void) +{ + long long x; + long result = vtest(&x, 0, 1); + if (result != 2 || x != 2) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc index 2cc2c0e..3748440 100644 --- a/gcc/tree-ssa-sccvn.cc +++ b/gcc/tree-ssa-sccvn.cc @@ -5718,19 +5718,6 @@ visit_reference_op_store (tree lhs, tree op, gimple *stmt) if (!resultsame) { - /* Only perform the following when being called from PRE - which embeds tail merging. */ - if (default_vn_walk_kind == VN_WALK) - { - assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op); - vn_reference_lookup (assign, vuse, VN_NOWALK, &vnresult, false); - if (vnresult) - { - VN_INFO (vdef)->visited = true; - return set_ssa_val_to (vdef, vnresult->result_vdef); - } - } - if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "No store match\n"); @@ -5755,7 +5742,9 @@ visit_reference_op_store (tree lhs, tree op, gimple *stmt) if (default_vn_walk_kind == VN_WALK) { assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op); - vn_reference_insert (assign, lhs, vuse, vdef); + vn_reference_lookup (assign, vuse, VN_NOWALK, &vnresult, false); + if (!vnresult) + vn_reference_insert (assign, lhs, vuse, vdef); } } else |