https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121853
Hongtao Liu <liuhongt at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |liuhongt at gcc dot gnu.org
--- Comment #6 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> backends are free to implement extendbfsf2 in a more efficient manner.
backend pattern is defined under !HONOR_NANS (BFmode), and with
-ffinite-math-only, x86 generates vpslld xmm0, xmm0, 16.
(define_expand "extendbfsf2"
[(set (match_operand:SF 0 "register_operand")
(unspec:SF
[(match_operand:BF 1 "register_operand")]
UNSPEC_CVTBFSF))]
"TARGET_SSE2 && !HONOR_NANS (BFmode)")
>float out = f - 0.0;
This would be optimized off by the middle-end, so I don't think it's equivilent
to static_cast if HONOR_NANS (BFmode).
