LoongArch: config: Added HAVE_LOONGARCH_VEC_ASM.

This patch checks if assembler supports vector instructions to
generate LASX/LSX code or not, and then define HAVE_LOONGARCH_VEC_ASM macro

We have added support for vector instructions in binutils-2.41
See:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=75b2f521b101d974354f6ce9ed7c054d8b2e3b7a

commit 75b2f521b101d974354f6ce9ed7c054d8b2e3b7a
Author: mengqinggang <mengqinggang@loongson.cn>
Date:   Thu Jun 22 10:35:28 2023 +0800

LoongArch: gas: Add lsx and lasx instructions support

gas/ChangeLog:

        * config/tc-loongarch.c (md_parse_option): Add lsx and lasx option.
        (loongarch_after_parse_args): Add lsx and lasx option.

opcodes/ChangeLog:

        * loongarch-opc.c (struct loongarch_ase): Add lsx and lasx
        instructions.

3 files changed, 48 insertions, 0 deletions

diff --git a/config.h.in b/config.h.in
index 44a34072a4..0dedc124f7 100644
--- a/config.h.in
+++ b/config.h.in
@@ -141,6 +141,11 @@
 /* LOONGARCH floating-point ABI for ld.so.  */
 #undef LOONGARCH_ABI_FRLEN
 
+/* Assembler support LoongArch LASX/LSX vector instructions.
+   This macro becomes obsolete when glibc increased the minimum
+   required version of GNU 'binutils' to 2.41 or later. */
+#define HAVE_LOONGARCH_VEC_ASM 0
+
 /* Linux specific: minimum supported kernel version.  */
 #undef	__LINUX_KERNEL_VERSION
 
diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure
index 52bd08a91e..b090e43a24 100644
--- a/sysdeps/loongarch/configure
+++ b/sysdeps/loongarch/configure
@@ -101,3 +101,31 @@ fi
 $as_echo "$libc_cv_loongarch_cmodel_medium" >&6; }
 config_vars="$config_vars
 have-cmodel-medium = $libc_cv_loongarch_cmodel_medium"
+
+# Check if asm support vector instructions.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for vector support in assembler" >&5
+$as_echo_n "checking for vector support in assembler... " >&6; }
+if ${libc_cv_loongarch_vec_asm+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.s <<\EOF
+        vld  $vr0, $sp, 0
+EOF
+if { ac_try='${CC-cc} -c $CFLAGS conftest.s -o conftest 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+  libc_cv_loongarch_vec_asm=yes
+else
+  libc_cv_loongarch_vec_asm=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_loongarch_vec_asm" >&5
+$as_echo "$libc_cv_loongarch_vec_asm" >&6; }
+if test $libc_cv_loongarch_vec_asm = yes; then
+  $as_echo "#define HAVE_LOONGARCH_VEC_ASM 1" >>confdefs.h
+
+fi
diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac
index cdd95fa512..39efccfd8f 100644
--- a/sysdeps/loongarch/configure.ac
+++ b/sysdeps/loongarch/configure.ac
@@ -62,3 +62,18 @@ AC_CACHE_CHECK(whether $CC supports option -mcmodel=medium,
     libc_cv_loongarch_cmodel_medium=no
   fi])
 LIBC_CONFIG_VAR([have-cmodel-medium], [$libc_cv_loongarch_cmodel_medium])
+
+# Check if asm support vector instructions.
+AC_CACHE_CHECK(for vector support in assembler, libc_cv_loongarch_vec_asm, [dnl
+cat > conftest.s <<\EOF
+        vld  $vr0, $sp, 0
+EOF
+if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest 1>&AS_MESSAGE_LOG_FD); then
+  libc_cv_loongarch_vec_asm=yes
+else
+  libc_cv_loongarch_vec_asm=no
+fi
+rm -f conftest*])
+if test $libc_cv_loongarch_vec_asm = yes; then
+  AC_DEFINE(HAVE_LOONGARCH_VEC_ASM)
+fi