--- Comment #12 from daney at gcc dot gnu dot org 2009-06-09 20:16 ---
(In reply to comment #6)
> Wouldn't be a special "noreturn" clobber in inline asm better suited for this
> then?
>
See: http://gcc.gnu.org/ml/gcc-patches/2000-01/msg00190.html for an opposing
opinion.
--
http:/
--- Comment #11 from daney at gcc dot gnu dot org 2009-06-09 20:12 ---
This is essentially __builtin_unreachable() for which I am working on a patch.
http://gcc.gnu.org/ml/gcc-patches/2009-06/msg00787.html
--
daney at gcc dot gnu dot org changed:
What|Removed
--- Comment #10 from rguenth at gcc dot gnu dot org 2009-03-01 22:41
---
Oh, patches welcome!
--
rguenth at gcc dot gnu dot org changed:
What|Removed |Added
--- Comment #9 from hpa at zytor dot com 2009-03-01 22:34 ---
> Though __builtin_not_reached () can be used to implement __builtin_assume (),
> so it may be more generally useful. if (i > 0) __builtin_not_reached (); will
> make GCC assume that i <= 0 on the other edge (of course we'd h
--- Comment #8 from rguenth at gcc dot gnu dot org 2009-02-20 09:57 ---
Though __builtin_not_reached () can be used to implement __builtin_assume (),
so it may be more generally useful. if (i > 0) __builtin_not_reached (); will
make GCC assume that i <= 0 on the other edge (of course we
--- Comment #7 from hpa at zytor dot com 2009-02-20 04:34 ---
A "noreturn" clobber would work just as well, obviously.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39252
--- Comment #6 from jakub at gcc dot gnu dot org 2009-02-19 23:02 ---
Wouldn't be a special "noreturn" clobber in inline asm better suited for this
then?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39252
--- Comment #5 from hpa at zytor dot com 2009-02-19 22:21 ---
Let me respectfully disagree, and explain why.
*You* can just create a builtin, but for us (the Linux kernel community) we
stare a multi-year pipeline in the face whenever we have to request a gcc
change. This feature would
--- Comment #4 from pinskia at gcc dot gnu dot org 2009-02-19 22:14 ---
Still you can make a builtin that does that. Even if it is a target builtin.
I think of having a target builtin is better than creating a generic
__builtin_not_reached.
--
http://gcc.gnu.org/bugzilla/show_bug.
--
hpa at zytor dot com changed:
What|Removed |Added
Status|WAITING |UNCONFIRMED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39252
--- Comment #3 from hpa at zytor dot com 2009-02-19 21:58 ---
Two reasons:
1. We have no control over what instruction __builtin_trap() will generate.
2. We require the address of the faulting instruction.
In particular, we currently have a construct which looks like:
#ifdef CONFIG_X8
--- Comment #2 from pinskia at gcc dot gnu dot org 2009-02-19 21:50 ---
Why again is __builtin_trap not useful for this purpose? You mention about
"assembly constructs" but why not instead implement those as builtins instead
of providing something which really can be abused?
--
pins
--- Comment #1 from hjl dot tools at gmail dot com 2009-02-19 20:51 ---
So __builtin_not_reached is just __builtin_trap which doesn't generate
any insn. It shouldn't be too hard to implement.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39252
--
hjl dot tools at gmail dot com changed:
What|Removed |Added
CC||hjl dot tools at gmail dot
|
14 matches
Mail list logo
