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| author | David Daney <ddaney@caviumnetworks.com> | 2009-06-11 23:55:45 +0000 |
|---|---|---|
| committer | David Daney <daney@gcc.gnu.org> | 2009-06-11 23:55:45 +0000 |
| commit | 468059bcbb8efdb31fd90369dc2ed122126413fe (patch) | |
| tree | 33e26cb48c7e5455995d1edba975d67cf78cad99 /gcc/cfgcleanup.c | |
| parent | f43def61eaf4f2e1f73c5af6ad806955b8f09949 (diff) | |
| download | gcc-468059bcbb8efdb31fd90369dc2ed122126413fe.tar.gz | |
re PR c/39252 (Request new feature __builtin_unreachable ())
2009-06-11 David Daney <ddaney@caviumnetworks.com>
PR c/39252
* doc/extend.texi ( __builtin_unreachable): Document new builtin.
* builtins.c (expand_builtin_unreachable): New function.
(expand_builtin): Handle BUILT_IN_UNREACHABLE case.
* builtins.def (BUILT_IN_UNREACHABLE): Add new builtin.
* cfgcleanup.c (try_optimize_cfg): Delete empty blocks with no
successors.
* cfgrtl.c (rtl_verify_flow_info): Handle empty blocks when
searching for missing barriers.
2009-06-11 David Daney <ddaney@caviumnetworks.com>
PR c/39252
* gcc.dg/builtin-unreachable-1.c: New test.
* gcc.dg/builtin-unreachable-2.c: Same.
From-SVN: r148403
Diffstat (limited to 'gcc/cfgcleanup.c')
| -rw-r--r-- | gcc/cfgcleanup.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 8da967a4ee0..a8b38d72472 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -1873,8 +1873,12 @@ try_optimize_cfg (int mode) edge s; bool changed_here = false; - /* Delete trivially dead basic blocks. */ - if (EDGE_COUNT (b->preds) == 0) + /* Delete trivially dead basic blocks. This is either + blocks with no predecessors, or empty blocks with no + successors. Empty blocks may result from expanding + __builtin_unreachable (). */ + if (EDGE_COUNT (b->preds) == 0 + || (EDGE_COUNT (b->succs) == 0 && BB_HEAD (b) == BB_END (b))) { c = b->prev_bb; if (dump_file) |