diff options
author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2014-02-28 13:14:23 +0000 |
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committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2014-02-28 13:14:23 +0000 |
commit | 0ab3f60312b3864458f772842fbeeaf3a3a1ad64 (patch) | |
tree | 0023e9b450aa8229d6be88c990e0dbfb8631eb19 /gcc/tree-cfgcleanup.c | |
parent | 7168cc342e96f1b0a2cd2aaaf4500ea2b17fd4f5 (diff) | |
download | gcc-0ab3f60312b3864458f772842fbeeaf3a3a1ad64.tar.gz |
2014-02-28 Richard Biener <rguenther@suse.de>
PR target/60280
* tree-cfgcleanup.c (tree_forwarder_block_p): Restrict
previous fix and only allow to remove trivial pre-headers
and latches. Also honor LOOPS_MAY_HAVE_MULTIPLE_LATCHES.
(remove_forwarder_block): Properly update the latch of
a loop.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@208222 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-cfgcleanup.c')
-rw-r--r-- | gcc/tree-cfgcleanup.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c index b5c384b902c..926d3000dc5 100644 --- a/gcc/tree-cfgcleanup.c +++ b/gcc/tree-cfgcleanup.c @@ -316,13 +316,22 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted) /* Protect loop preheaders and latches if requested. */ if (dest->loop_father->header == dest) { - if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) - && bb->loop_father->header != dest) - return false; - - if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES) - && bb->loop_father->header == dest) - return false; + if (bb->loop_father == dest->loop_father) + { + if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) + return false; + /* If bb doesn't have a single predecessor we'd make this + loop have multiple latches. Don't do that if that + would in turn require disambiguating them. */ + return (single_pred_p (bb) + || loops_state_satisfies_p + (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); + } + else if (bb->loop_father == loop_outer (dest->loop_father)) + return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS); + /* Always preserve other edges into loop headers that are + not simple latches or preheaders. */ + return false; } } @@ -417,6 +426,10 @@ remove_forwarder_block (basic_block bb) can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest); + basic_block pred = NULL; + if (single_pred_p (bb)) + pred = single_pred (bb); + /* Redirect the edges. */ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) { @@ -510,7 +523,7 @@ remove_forwarder_block (basic_block bb) /* Adjust latch infomation of BB's parent loop as otherwise the cfg hook has a hard time not to kill the loop. */ if (current_loops && bb->loop_father->latch == bb) - bb->loop_father->latch = dest; + bb->loop_father->latch = pred; /* And kill the forwarder block. */ delete_basic_block (bb); |