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| author | Richard Guenther <rguenther@suse.de> | 2012-08-22 13:17:26 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2012-08-22 13:17:26 +0000 |
| commit | 9bb06c2a9f8b83179cb76ba928b22aa3a2b57501 (patch) | |
| tree | 34c557fa3311568283166d9d30556e185c013ce5 /gcc/tree-ssa-sccvn.c | |
| parent | 4ad149191495f24d32416840e5aaca967e16afb2 (diff) | |
| download | gcc-9bb06c2a9f8b83179cb76ba928b22aa3a2b57501.zip gcc-9bb06c2a9f8b83179cb76ba928b22aa3a2b57501.tar.gz gcc-9bb06c2a9f8b83179cb76ba928b22aa3a2b57501.tar.bz2 | |
re PR tree-optimization/46590 (long compile time with -O2 and many loops)
2012-08-22 Richard Guenther <rguenther@suse.de>
PR tree-optimization/46590
* tree-ssa-alias.h (get_continuation_for_phi): Add alias query
counter output argument.
(walk_non_aliased_vuses): Add alias query counter argument
to the walker callback.
* tree-ssa-alias.c (maybe_skip_until): Add alias query counter
output argument and count alias queries.
(get_continuation_for_phi_1): Likewise.
(get_continuation_for_phi): Likewise.
(walk_non_aliased_vuses): Add alias query counter argument
to the walker callback and allow it to abort the walk by
returning -1.
* tree-ssa-pre.c (translate_vuse_through_block): Adjust.
* tree-ssa-sccvn.c (vn_reference_lookup_2): Add alias query
counter parmeter, abort walk if that is bigger than
--param sccvn-max-alias-queries-per-access.
* params.def (sccvn-max-alias-queries-per-access): New param.
* doc/invoke.texi (sccvn-max-alias-queries-per-access): Document.
From-SVN: r190594
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 216d3f6..5d5a91c 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -1330,12 +1330,19 @@ static vn_lookup_kind default_vn_walk_kind; with the current VUSE and performs the expression lookup. */ static void * -vn_reference_lookup_2 (ao_ref *op ATTRIBUTE_UNUSED, tree vuse, void *vr_) +vn_reference_lookup_2 (ao_ref *op ATTRIBUTE_UNUSED, tree vuse, + unsigned int cnt, void *vr_) { vn_reference_t vr = (vn_reference_t)vr_; void **slot; hashval_t hash; + /* This bounds the stmt walks we perform on reference lookups + to O(1) instead of O(N) where N is the number of dominating + stores. */ + if (cnt > (unsigned) PARAM_VALUE (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS)) + return (void *)-1; + if (last_vuse_ptr) *last_vuse_ptr = vuse; |