https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115454
Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2024-06-13
Assignee|unassigned at gcc dot gnu.org |mkretz at gcc dot
gnu.org
--- Comment #1 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> ---
Confirmed. The != compare returns an 8-bit mask (internally) for a 4-element
simd_mask in
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libstdc%2B%2B-v3/include/experimental/bits/simd_x86.h;h=4ab933b573c614654902d6f5747d53e39f4b100f;hb=HEAD#l2350.
The high 4 bits are incorrectly set because of the ~ operator on the resulting
mask. Those bits are not cleared before calling std::bit_width - 1, which is
why the result is unconditionally 7.
You can work around the bug by replacing 'e != -1' with '!(e == -1)' for the
time being.
