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| author | Richard Biener <rguenther@suse.de> | 2018-09-25 12:51:57 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2018-09-25 12:51:57 +0000 |
| commit | a0d013bdc22353a1b835c5f009259ae032a6b84b (patch) | |
| tree | b154d7d697ee8d70b7b640b709975ef67447d3c7 /gcc/tree-ssa-sccvn.c | |
| parent | 5d6749d1f241223353cba6cb637738bb5b698756 (diff) | |
| download | gcc-a0d013bdc22353a1b835c5f009259ae032a6b84b.zip gcc-a0d013bdc22353a1b835c5f009259ae032a6b84b.tar.gz gcc-a0d013bdc22353a1b835c5f009259ae032a6b84b.tar.bz2 | |
re PR tree-optimization/87402 (ICE in set_ssa_val_to, at tree-ssa-sccvn.c:3645)
2018-09-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/87402
* tree-ssa-sccvn.c (SSA_VISITED): Remove unused function.
(visit_phi): Re-instantiate handling of supposed to be VARYING
but non-VARYING backedge value.
* gcc.dg/torture/pr87402.c: New testcase.
From-SVN: r264566
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index cee3d73..5a05dfb 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -464,15 +464,6 @@ SSA_VAL (tree x, bool *visited = NULL) return tem && tem->visited ? tem->valnum : x; } -/* Return whether X was visited. */ - -inline bool -SSA_VISITED (tree x) -{ - vn_ssa_aux_t tem = vn_ssa_aux_hash->find_with_hash (x, SSA_NAME_VERSION (x)); - return tem && tem->visited; -} - /* Return the SSA value of the VUSE x, supporting released VDEFs during elimination which will value-number the VDEF to the associated VUSE (but not substitute in the whole lattice). */ @@ -4196,7 +4187,10 @@ visit_phi (gimple *phi, bool *inserted, bool backedges_varying_p) } } - /* If we value-number a virtual operand never value-number to the + /* If the value we want to use is flowing over the backedge and we + should take it as VARYING but it has a non-VARYING value drop to + VARYING. + If we value-number a virtual operand never value-number to the value from the backedge as that confuses the alias-walking code. See gcc.dg/torture/pr87176.c. If the value is the same on a non-backedge everything is OK though. */ @@ -4204,7 +4198,8 @@ visit_phi (gimple *phi, bool *inserted, bool backedges_varying_p) && !seen_non_backedge && TREE_CODE (backedge_val) == SSA_NAME && sameval == backedge_val - && SSA_NAME_IS_VIRTUAL_OPERAND (backedge_val)) + && (SSA_NAME_IS_VIRTUAL_OPERAND (backedge_val) + || SSA_VAL (backedge_val) != backedge_val)) /* Note this just drops to VARYING without inserting the PHI into the hashes. */ result = PHI_RESULT (phi); |