[gcc r14-7097] LoongArch: testsuite: Add loongarch support to slp-21.c.

[LuluCheng]

https://gcc.gnu.org/g:898c39ca80b0cd0e5a19de5e46a5802b6cadc39c

commit r14-7097-g898c39ca80b0cd0e5a19de5e46a5802b6cadc39c
Author: chenxiaolong <chenxiaolong@loongson.cn>
Date:   Wed Jan 10 15:25:21 2024 +0800

    LoongArch: testsuite: Add loongarch support to slp-21.c.
    
    The function of this test is to check that the compiler supports vectorization
    using SLP and vec_{load/store/*}_lanes. However, vec_{load/store/*}_lanes are
    not supported on LoongArch, such as the corresponding "st4/ld4" directives on
    aarch64.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/vect/slp-21.c: Add loongarch.

Diff:
---
 gcc/testsuite/gcc.dg/vect/slp-21.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/vect/slp-21.c b/gcc/testsuite/gcc.dg/vect/slp-21.c
index 712a73b69d7..58751688414 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-21.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-21.c
@@ -213,7 +213,7 @@ int main (void)
 
    Not all vect_perm targets support that, and it's a bit too specific to have
    its own effective-target selector, so we just test targets directly.  */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { target { powerpc64*-*-* s390*-*-* } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_strided4 && { ! { powerpc64*-*-* s390*-*-* } } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { target { powerpc64*-*-* s390*-*-* loongarch*-*-* } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_strided4 && { ! { powerpc64*-*-* s390*-*-* loongarch*-*-* } } } } } } */
 /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect"  { target { ! { vect_strided4 } } } } } */