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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/builtins.c | |
| parent | f43def61eaf4f2e1f73c5af6ad806955b8f09949 (diff) | |
| download | gcc-468059bcbb8efdb31fd90369dc2ed122126413fe.zip gcc-468059bcbb8efdb31fd90369dc2ed122126413fe.tar.gz gcc-468059bcbb8efdb31fd90369dc2ed122126413fe.tar.bz2 | |
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/builtins.c')
| -rw-r--r-- | gcc/builtins.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/gcc/builtins.c b/gcc/builtins.c index a555e4f..9891978 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -5298,6 +5298,17 @@ expand_builtin_trap (void) emit_barrier (); } +/* Expand a call to __builtin_unreachable. We do nothing except emit + a barrier saying that control flow will not pass here. + + It is the responsibility of the program being compiled to ensure + that control flow does never reach __builtin_unreachable. */ +static void +expand_builtin_unreachable (void) +{ + emit_barrier (); +} + /* Expand EXP, a call to fabs, fabsf or fabsl. Return NULL_RTX if a normal call should be emitted rather than expanding the function inline. If convenient, the result should be placed @@ -6795,6 +6806,10 @@ expand_builtin (tree exp, rtx target, rtx subtarget, enum machine_mode mode, expand_builtin_trap (); return const0_rtx; + case BUILT_IN_UNREACHABLE: + expand_builtin_unreachable (); + return const0_rtx; + case BUILT_IN_PRINTF: target = expand_builtin_printf (exp, target, mode, false); if (target) |