From: Florian Weimer <fw@deneb.enyo.de>
To: Marek Polacek <polacek@redhat.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
Richard Sandiford <richard.sandiford@arm.com>
Subject: Re: PATCH to add more FALLTHRU markers
Date: Tue, 27 Sep 2016 19:33:00 -0000 [thread overview]
Message-ID: <874m51xhtl.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20160927191847.GJ3223@redhat.com> (Marek Polacek's message of "Tue, 27 Sep 2016 21:18:48 +0200")
* 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.
next prev parent reply other threads:[~2016-09-27 19:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-27 16:55 Marek Polacek
2016-09-27 19:00 ` Richard Sandiford
2016-09-29 17:22 ` Marek Polacek
2016-09-27 19:08 ` Florian Weimer
2016-09-27 19:22 ` Marek Polacek
2016-09-27 19:33 ` Florian Weimer [this message]
2016-09-27 19:39 ` Marek Polacek
2016-09-27 20:13 ` Jakub Jelinek
2016-09-29 17:17 ` Marek Polacek
2016-09-29 20:21 ` Jakub Jelinek
2016-09-30 21:31 ` [PATCH] FALLTHRU markers for sse.md and some cleanups Jakub Jelinek
2016-10-01 8:31 ` Uros Bizjak
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