On Tue, Sep 27, 2016 at 09:29:10PM +0200, Florian Weimer wrote:
> * Marek Polacek:
>
> > On Tue, Sep 27, 2016 at 08:58:59PM +0200, Florian Weimer wrote:
> >> * Marek Polacek:
> >>
> >> > @@ -11498,21 +11508,23 @@
> >> > case V64QImode:
> >> > case V32HImode:
> >> > if (TARGET_AVX512F)
> >> > - {
> >> > - tmp = "p<logic>";
> >> > - ssesuffix = "q";
> >> > - break;
> >> > - }
> >> > + {
> >> > + tmp = "p<logic>";
> >> > + ssesuffix = "q";
> >> > + break;
> >> > + }
> >> > + /* FALLTHRU */
> >> > case V32QImode:
> >> > case V16HImode:
> >> > case V16QImode:
> >> > case V8HImode:
> >> > if (TARGET_AVX512VL || TARGET_AVX2 || TARGET_SSE2)
> >> > - {
> >> > - tmp = "p<logic>";
> >> > - ssesuffix = TARGET_AVX512VL ? "q" : "";
> >> > - break;
> >> > - }
> >> > + {
> >> > + tmp = "p<logic>";
> >> > + ssesuffix = TARGET_AVX512VL ? "q" : "";
> >> > + break;
> >> > + }
> >> > + /* FALLTHRU */
> >> > default:
> >> > gcc_unreachable ();
> >> > }
> >>
> >> Why isn't this a bug? Wouldn't we want to reach gcc_unreachable ()
> >> if, for example !TARGET_AVX512F and TARGET_SSE2?
> >
> > ?? In that case the FALLTHRU should be there if it's intentional that
> > we may fall through to default. Otherwise not sure what you mean.
>
> Not sure if I read this code correctly, but if we fall through from
> V32HImode, and we have TARGET_SSE2 set, we execute this code:
>
> tmp = "p<logic>";
> ssesuffix = TARGET_AVX512VL ? "q" : "";
>
> And not gcc_unreachable (), as is probably intended.
Kyrill, can you please decide? Thanks.
Marek
