From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: <libc-alpha@sourceware.org>
Cc: Khem Raj <raj.khem@gmail.com>, Ross Burton <ross.burton@arm.com>
Subject: [PATCH] aarch64: fix check for SVE support in assembler
Date: Thu, 14 Mar 2024 13:30:12 +0000 [thread overview]
Message-ID: <20240314133012.16925-1-szabolcs.nagy@arm.com> (raw)
Due to GCC bug 110901 -mcpu can override -march setting when compiling
asm code and thus a compiler targetting a specific cpu can fail the
configure check even when binutils gas supports SVE.
The workaround is that explicit .arch directive overrides both -mcpu
and -march, and since that's what the actual SVE memcpy uses the
configure check should use that too even if the GCC issue is fixed
independently.
---
note: i found this in yocto, and i think it's a better fix than
https://git.yoctoproject.org/poky/tree/meta/recipes-core/glibc/glibc/0023-aarch64-configure-Pass-mcpu-along-with-march-to-dete.patch
sysdeps/aarch64/configure | 5 +++--
sysdeps/aarch64/configure.ac | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
mode change 100644 => 100755 sysdeps/aarch64/configure
diff --git a/sysdeps/aarch64/configure b/sysdeps/aarch64/configure
old mode 100644
new mode 100755
index ca57edce47..9606137e8d
--- a/sysdeps/aarch64/configure
+++ b/sysdeps/aarch64/configure
@@ -325,9 +325,10 @@ then :
printf %s "(cached) " >&6
else $as_nop
cat > conftest.s <<\EOF
- ptrue p0.b
+ .arch armv8.2-a+sve
+ ptrue p0.b
EOF
-if { ac_try='${CC-cc} -c -march=armv8.2-a+sve conftest.s 1>&5'
+if { ac_try='${CC-cc} -c conftest.s 1>&5'
{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
(eval $ac_try) 2>&5
ac_status=$?
diff --git a/sysdeps/aarch64/configure.ac b/sysdeps/aarch64/configure.ac
index 27874eceb4..56d12d661d 100644
--- a/sysdeps/aarch64/configure.ac
+++ b/sysdeps/aarch64/configure.ac
@@ -90,9 +90,10 @@ LIBC_CONFIG_VAR([aarch64-variant-pcs], [$libc_cv_aarch64_variant_pcs])
# Check if asm support armv8.2-a+sve
AC_CACHE_CHECK([for SVE support in assembler], [libc_cv_aarch64_sve_asm], [dnl
cat > conftest.s <<\EOF
- ptrue p0.b
+ .arch armv8.2-a+sve
+ ptrue p0.b
EOF
-if AC_TRY_COMMAND(${CC-cc} -c -march=armv8.2-a+sve conftest.s 1>&AS_MESSAGE_LOG_FD); then
+if AC_TRY_COMMAND(${CC-cc} -c conftest.s 1>&AS_MESSAGE_LOG_FD); then
libc_cv_aarch64_sve_asm=yes
else
libc_cv_aarch64_sve_asm=no
--
2.25.1
next reply other threads:[~2024-03-14 13:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 13:30 Szabolcs Nagy [this message]
2024-03-14 13:57 ` [PATCH] aarch64: fix check for SVE support in assembler Florian Weimer
2024-03-14 17:27 ` Khem Raj
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/libc/involved.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240314133012.16925-1-szabolcs.nagy@arm.com \
--to=szabolcs.nagy@arm.com \
--cc=libc-alpha@sourceware.org \
--cc=raj.khem@gmail.com \
--cc=ross.burton@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).