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| author | Marek Polacek <polacek@redhat.com> | 2012-12-02 20:16:09 +0000 |
|---|---|---|
| committer | Marek Polacek <mpolacek@gcc.gnu.org> | 2012-12-02 20:16:09 +0000 |
| commit | 60cec1fd88bb0922387cd06d381fc73230a50fd6 (patch) | |
| tree | 994e3f067e69fffac35076de32d2c1530f1af0a2 /gcc/cprop.c | |
| parent | bde8c9629a161f292ba1d9c97c28e7cd61806eb9 (diff) | |
| download | gcc-60cec1fd88bb0922387cd06d381fc73230a50fd6.zip gcc-60cec1fd88bb0922387cd06d381fc73230a50fd6.tar.gz gcc-60cec1fd88bb0922387cd06d381fc73230a50fd6.tar.bz2 | |
re PR middle-end/54838 (ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer)
PR54838
From-SVN: r194060
Diffstat (limited to 'gcc/cprop.c')
| -rw-r--r-- | gcc/cprop.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/gcc/cprop.c b/gcc/cprop.c index 3fb266a..ec896a4 100644 --- a/gcc/cprop.c +++ b/gcc/cprop.c @@ -1510,13 +1510,28 @@ bypass_block (basic_block bb, rtx setcc, rtx jump) if (note) find_used_regs (&XEXP (note, 0), NULL); - may_be_loop_header = false; - FOR_EACH_EDGE (e, ei, bb->preds) - if (e->flags & EDGE_DFS_BACK) - { - may_be_loop_header = true; - break; - } + /* Determine whether there are more latch edges. Threading through + a loop header with more than one latch is delicate, see e.g. + tree-ssa-threadupdate.c:thread_through_loop_header. */ + if (current_loops) + { + may_be_loop_header = bb == bb->loop_father->header; + if (may_be_loop_header + && bb->loop_father->latch == NULL) + return 0; + } + else + { + unsigned n_back_edges = 0; + FOR_EACH_EDGE (e, ei, bb->preds) + if (e->flags & EDGE_DFS_BACK) + n_back_edges++; + + may_be_loop_header = n_back_edges > 0; + + if (n_back_edges > 1) + return 0; + } change = 0; for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) |