[Bug inline-asm/49611] Inline asm should support input/output of flags

["gcc.hall at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49611

--- Comment #12 from Jeremy <gcc.hall at gmail dot com> ---
Hi David,
That's very interesting.  Its not in gcc 5.2.0 released yesterday though.
It probably does a setcc on x86 which doesn't really gain much, but on ARM
it could be useful.
More useful (as of gcc 5.0) is the new __builtin_xxx_overflow which uses
the overflow flag directly.   So for int16_t  operands for example:
    if(   __builtin_add_overflow( a, b, &result)  )
         printf( "overflow");
it would emit "addw; jno".

Jeremy



On 17 July 2015 at 06:41, gccbugzilla at limegreensocks dot com <
gcc-bugzilla@gcc.gnu.org> wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49611
>
> --- Comment #11 from David <gccbugzilla at limegreensocks dot com> ---
> Apparently this feature has been checked in:
> https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#FlagOutputOperands
>
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