From: Jakub Jelinek <jakub@redhat.com>
To: YunQiang Su <syq@gcc.gnu.org>
Cc: gcc-patches@gcc.gnu.org, ian@airs.com, pinskia@gmail.com,
matoro_mailinglist_gcc-patches@matoro.tk
Subject: Re: [PATCH 1/2] MIPS: host_detect_local_cpu, init ret with concat [PR112759]
Date: Mon, 18 Dec 2023 09:10:47 +0100 [thread overview]
Message-ID: <ZX/+h9Eqyvfy7fcl@tucnak> (raw)
In-Reply-To: <20231218034422.2668628-1-syq@gcc.gnu.org>
On Mon, Dec 18, 2023 at 11:44:21AM +0800, YunQiang Su wrote:
> The function `reconcat` cannot append string(s) to NULL,
> as the concat process will stop at the first NULL.
>
> Let's initialize `ret` with `concat (" ", NULL)`, then
> it can be used by reconcat.
>
> gcc/
>
> PR target/112759
> * config/mips/driver-native.cc (host_detect_local_cpu):
> initialize ret with concat, so that it can be used by
> reconcat later.
> ---
> gcc/config/mips/driver-native.cc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/config/mips/driver-native.cc b/gcc/config/mips/driver-native.cc
> index afc276f5278..471d1925eff 100644
> --- a/gcc/config/mips/driver-native.cc
> +++ b/gcc/config/mips/driver-native.cc
> @@ -44,7 +44,7 @@ const char *
> host_detect_local_cpu (int argc, const char **argv)
> {
> const char *cpu = NULL;
> - char *ret = NULL;
> + char *ret = concat(" ", NULL);
> char buf[128];
> FILE *f;
> bool arch;
> --
> 2.39.2
The formatting is wrong (no space after concat), but more importantly,
I don't think you want to return " " rather than NULL if there isn't
anything known and it is unnecessary to prefix everything with a space
when
gnu-user.h: " %{march=native:%<march=native %:local_cpu_detect(arch)}" \
gnu-user.h: " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"
space is already present. Given the simple thing the function does,
I think much better would be to avoid any reconcat calls and just do one
concat, i.e.
--- gcc/config/mips/driver-native.cc 2023-01-02 09:32:58.422764590 +0100
+++ gcc/config/mips/driver-native.cc 2023-12-18 09:08:39.547609739 +0100
@@ -44,6 +44,7 @@ const char *
host_detect_local_cpu (int argc, const char **argv)
{
const char *cpu = NULL;
+ const char *nan2008 = "";
char *ret = NULL;
char buf[128];
FILE *f;
@@ -90,7 +91,7 @@ host_detect_local_cpu (int argc, const c
fallback_cpu:
#if defined (__mips_nan2008)
- ret = reconcat (ret, " -mnan=2008 ", NULL);
+ nan2008 = "-mnan=2008 ";
#endif
#ifdef HAVE_GETAUXVAL
@@ -104,7 +105,9 @@ fallback_cpu:
#endif
if (cpu)
- ret = reconcat (ret, ret, "-m", argv[0], "=", cpu, NULL);
+ ret = concat (nan2008, "-m", argv[0], "=", cpu, NULL);
+ else if (nan2008)
+ ret = concat (nan2008, NULL);
return ret;
}
Or, if you really want to use reconcat, drop that space from
before -mnan=2008 and use
ret = reconcat (ret, ret ? ret : "", "-m", argv[0], "=", cpu, NULL);
Jakub
next prev parent reply other threads:[~2023-12-18 8:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-18 3:44 YunQiang Su
2023-12-18 3:44 ` [PATCH 2/2] libiberty/reconcat: Add note about append string to NULL YunQiang Su
2023-12-18 7:56 ` Jakub Jelinek
2023-12-18 8:10 ` Jakub Jelinek [this message]
2023-12-18 22:59 ` [PATCH 1/2] MIPS: host_detect_local_cpu, init ret with concat [PR112759] YunQiang Su
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