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* [Bug target/81759] Improve data tracking for _pext_u64 and __builtin_ffsll
[not found] <bug-81759-4@http.gcc.gnu.org/bugzilla/>
@ 2024-03-15 4:31 ` pinskia at gcc dot gnu.org
2024-03-15 4:32 ` [Bug target/81759] Improve data tracking for _pext_u64 pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-03-15 4:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81759
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Daniel Fruzynski from comment #2)
> Looks that __builtin_ffs does not check if input value is nonzero at all.
> Assembler code for following code also has unnecessary instructions:
>
> [code]
> unsigned int test(unsigned int n)
> {
> if (n == 0)
> __builtin_unreachable();
> return __builtin_ffs(n) - 1;
> }
> [/code]
The above is now handled since GCC 11.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug target/81759] Improve data tracking for _pext_u64
[not found] <bug-81759-4@http.gcc.gnu.org/bugzilla/>
2024-03-15 4:31 ` [Bug target/81759] Improve data tracking for _pext_u64 and __builtin_ffsll pinskia at gcc dot gnu.org
@ 2024-03-15 4:32 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-03-15 4:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81759
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2017-08-08 00:00:00 |2024-3-14
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
_pext_u64 is still opaque idea to gimple.
^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] <bug-81759-4@http.gcc.gnu.org/bugzilla/>
2024-03-15 4:31 ` [Bug target/81759] Improve data tracking for _pext_u64 and __builtin_ffsll pinskia at gcc dot gnu.org
2024-03-15 4:32 ` [Bug target/81759] Improve data tracking for _pext_u64 pinskia at gcc dot gnu.org
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