From: Mike Frysinger <vapier@gentoo.org>
To: Andrew Burgess <aburgess@redhat.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [PATCH 4/5] sim/erc32: avoid dereferencing type-punned pointer warnings
Date: Sun, 23 Oct 2022 18:19:23 +0545 [thread overview]
Message-ID: <Y1U0z8cg4NTyVWS3@vapier> (raw)
In-Reply-To: <b36f2b9339266fdef2e34970f932782925744ba4.1665578246.git.aburgess@redhat.com>
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On 12 Oct 2022 13:38, Andrew Burgess via Gdb-patches wrote:
> When building the erc32 simulator I get a few warnings like this:
>
> /tmp/build/sim/../../src/sim/erc32/exec.c:1377:21: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
> 1377 | sregs->fs[rd] = *((float32 *) & ddata[0]);
> | ~^~~~~~~~~~~~~~~~~~~~~~~
>
> The type of '& ddata[0]' will be 'uint32_t *', which is what triggers
> the warning.
>
> This commit uses an intermediate pointer of type 'char *' when
> performing the type-punning, which is well-defined behaviour, and will
> silence the above warning.
this is kind of a poor fix. if we can't arrange for the pointers to be
the right type, at least a memcpy would be better.
-mike
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next prev parent reply other threads:[~2022-10-23 13:48 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-12 12:38 [PATCH 0/5] Silence some build warnings in various simulators Andrew Burgess
2022-10-12 12:38 ` [PATCH 1/5] sim/cgen: mask uninitialized variable warning in cgen-run.c Andrew Burgess
2022-10-23 12:30 ` Mike Frysinger
2022-10-24 15:57 ` Andrew Burgess
2022-10-24 15:59 ` Mike Frysinger
2022-10-27 15:53 ` Andrew Burgess
2022-10-12 12:38 ` [PATCH 2/5] sim/ppc: fix warnings related to printf format strings Andrew Burgess
2022-10-12 12:46 ` Tsukasa OI
2022-10-12 13:50 ` Andrew Burgess
2022-10-23 12:20 ` Mike Frysinger
2022-10-24 15:41 ` Andrew Burgess
2022-10-12 12:38 ` [PATCH 3/5] sim/ppc: mark device_error function as ATTRIBUTE_NORETURN Andrew Burgess
2022-10-12 12:38 ` [PATCH 4/5] sim/erc32: avoid dereferencing type-punned pointer warnings Andrew Burgess
2022-10-12 14:11 ` Pedro Alves
2022-10-12 17:02 ` Lancelot SIX
2022-10-13 10:35 ` Andrew Burgess
2022-10-13 10:49 ` Pedro Alves
2022-10-23 12:34 ` Mike Frysinger [this message]
2022-10-24 15:42 ` Andrew Burgess
2022-10-12 12:38 ` [PATCH 5/5] sim/iq2000: silence pointer-sign warnings Andrew Burgess
2022-10-23 12:32 ` Mike Frysinger
2022-10-24 15:45 ` Andrew Burgess
2022-10-26 8:51 ` Mike Frysinger
2022-10-14 17:50 ` [PATCH 0/5] Silence some build warnings in various simulators Tom Tromey
2022-10-19 13:34 ` Andrew Burgess
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