diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-08-11 09:02:04 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-08-11 09:02:04 +0000 |
| commit | ec969ce4161538b561592a032eca6dcfaf513596 (patch) | |
| tree | 8d5fbd4bacf84fae62437497b5b8a89b8f7f2ed5 /gcc/cfgloopmanip.c | |
| parent | 25482c165531711569fc25c7811c5e339e54e4f5 (diff) | |
| download | gcc-ec969ce4161538b561592a032eca6dcfaf513596.tar.gz | |
2016-08-11 Richard Biener <rguenther@suse.de>
PR tree-optimization/72772
* cfgloopmanip.c (create_preheader): Use split_edge if there
is a single loop entry, avoiding degenerate PHIs.
* gcc.dg/graphite/pr35356-1.c: Adjust.
* gcc.dg/tree-ssa/pr59597.c: Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239357 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/cfgloopmanip.c')
| -rw-r--r-- | gcc/cfgloopmanip.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c index 20476d70459..487b91df0e5 100644 --- a/gcc/cfgloopmanip.c +++ b/gcc/cfgloopmanip.c @@ -1497,7 +1497,7 @@ has_preds_from_loop (basic_block block, struct loop *loop) basic_block create_preheader (struct loop *loop, int flags) { - edge e, fallthru; + edge e; basic_block dummy; int nentry = 0; bool irred = false; @@ -1544,9 +1544,14 @@ create_preheader (struct loop *loop, int flags) mfb_kj_edge = loop_latch_edge (loop); latch_edge_was_fallthru = (mfb_kj_edge->flags & EDGE_FALLTHRU) != 0; - fallthru = make_forwarder_block (loop->header, mfb_keep_just, NULL); - dummy = fallthru->src; - loop->header = fallthru->dest; + if (nentry == 1) + dummy = split_edge (single_entry); + else + { + edge fallthru = make_forwarder_block (loop->header, mfb_keep_just, NULL); + dummy = fallthru->src; + loop->header = fallthru->dest; + } /* Try to be clever in placing the newly created preheader. The idea is to avoid breaking any "fallthruness" relationship between blocks. |