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* [Bug target/93990] [x86] Silly code generation for _addcarry_u32/_addcarry_u64
[not found] <bug-93990-4@http.gcc.gnu.org/bugzilla/>
@ 2021-08-29 9:14 ` pinskia at gcc dot gnu.org
2021-09-09 6:50 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-29 9:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93990
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |NEW
Severity|normal |enhancement
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
_addcarry_u64(0, a, c, &result0) can definitely be folded into
__builtin_uadd_overflowll/.ADD_OVERFLOW without any troubles.
The second _addcarry_u64 here since the result is not used can be folded into
just an a few adds.
That leaves if there case where the first argument is non-zero and the result
is used. I think going the route that Jakub mentions is best for this last
case.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug target/93990] [x86] Silly code generation for _addcarry_u32/_addcarry_u64
[not found] <bug-93990-4@http.gcc.gnu.org/bugzilla/>
2021-08-29 9:14 ` [Bug target/93990] [x86] Silly code generation for _addcarry_u32/_addcarry_u64 pinskia at gcc dot gnu.org
@ 2021-09-09 6:50 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-09-09 6:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93990
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #5)
> That leaves if there case where the first argument is non-zero and the
> result is used. I think going the route that Jakub mentions is best for this
> last case.
Maybe even generic builtins/internal functions for this case even as clang has
__builtin_addc, etc.
^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] <bug-93990-4@http.gcc.gnu.org/bugzilla/>
2021-08-29 9:14 ` [Bug target/93990] [x86] Silly code generation for _addcarry_u32/_addcarry_u64 pinskia at gcc dot gnu.org
2021-09-09 6:50 ` pinskia at gcc dot gnu.org
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