diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-05-02 13:11:27 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-05-02 13:11:27 +0000 |
| commit | b81ffaee0b20899eed61b6ccd661c3fbe37eb5ab (patch) | |
| tree | 2bebdc1626ad94e349f185dd860edaef39f741f1 /gcc/tree-ssa-sccvn.c | |
| parent | b15e129ddd842fbe2bd1b3d88dc72b2ea5d9bd33 (diff) | |
| download | gcc-b81ffaee0b20899eed61b6ccd661c3fbe37eb5ab.tar.gz | |
2011-05-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/48822
* tree-ssa-sccvn.c (set_ssa_val_to): Never go up the lattice.
(process_scc): Indicate which iteration we start.
* gcc.dg/torture/pr48822.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@173250 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index ab56e3d534a..8f96d6c0356 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -2241,12 +2241,26 @@ print_scc (FILE *out, VEC (tree, heap) *scc) static inline bool set_ssa_val_to (tree from, tree to) { - tree currval; + tree currval = SSA_VAL (from); - if (from != to - && TREE_CODE (to) == SSA_NAME - && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to)) - to = from; + if (from != to) + { + if (currval == from) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Not changing value number of "); + print_generic_expr (dump_file, from, 0); + fprintf (dump_file, " from VARYING to "); + print_generic_expr (dump_file, to, 0); + fprintf (dump_file, "\n"); + } + return false; + } + else if (TREE_CODE (to) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to)) + to = from; + } /* The only thing we allow as value numbers are VN_TOP, ssa_names and invariants. So assert that here. */ @@ -2263,8 +2277,6 @@ set_ssa_val_to (tree from, tree to) print_generic_expr (dump_file, to, 0); } - currval = SSA_VAL (from); - if (currval != to && !operand_equal_p (currval, to, OEP_PURE_SAME)) { VN_INFO (from)->valnum = to; @@ -3280,6 +3292,8 @@ process_scc (VEC (tree, heap) *scc) { changed = false; iterations++; + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Starting iteration %d\n", iterations); /* As we are value-numbering optimistically we have to clear the expression tables and the simplified expressions in each iteration until we converge. */ |