LoongArch: Add ifunc support for memcmp{aligned, lsx, lasx}

According to glibc memcmp microbenchmark test results(Add generic
memcmp), this implementation have performance improvement
except the length is less than 3, details as below:

Name             Percent of time reduced
memcmp-lasx      16%-74%
memcmp-lsx       20%-50%
memcmp-aligned   5%-20%

7 files changed, 861 insertions, 0 deletions

diff --git a/sysdeps/loongarch/lp64/multiarch/Makefile b/sysdeps/loongarch/lp64/multiarch/Makefile
index 216886c551..360a6718c0 100644
--- a/sysdeps/loongarch/lp64/multiarch/Makefile
+++ b/sysdeps/loongarch/lp64/multiarch/Makefile
@@ -34,5 +34,8 @@ sysdep_routines += \
   memset-unaligned \
   memset-lsx \
   memset-lasx \
+  memcmp-aligned \
+  memcmp-lsx \
+  memcmp-lasx \
 # sysdep_routines
 endif
diff --git a/sysdeps/loongarch/lp64/multiarch/ifunc-impl-list.c b/sysdeps/loongarch/lp64/multiarch/ifunc-impl-list.c
index 37f60dde91..e397d58c9d 100644
--- a/sysdeps/loongarch/lp64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/loongarch/lp64/multiarch/ifunc-impl-list.c
@@ -127,5 +127,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, memset, 1, __memset_aligned)
 	      )
 
+  IFUNC_IMPL (i, name, memcmp,
+#if !defined __loongarch_soft_float
+	      IFUNC_IMPL_ADD (array, i, memcmp, SUPPORT_LASX, __memcmp_lasx)
+	      IFUNC_IMPL_ADD (array, i, memcmp, SUPPORT_LSX, __memcmp_lsx)
+#endif
+	      IFUNC_IMPL_ADD (array, i, memcmp, 1, __memcmp_aligned)
+	      )
   return i;
 }
diff --git a/sysdeps/loongarch/lp64/multiarch/ifunc-memcmp.h b/sysdeps/loongarch/lp64/multiarch/ifunc-memcmp.h
new file mode 100644
index 0000000000..04adc2e561
--- /dev/null
+++ b/sysdeps/loongarch/lp64/multiarch/ifunc-memcmp.h
@@ -0,0 +1,40 @@
+/* Common definition for memcmp ifunc selections.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <ldsodefs.h>
+#include <ifunc-init.h>
+
+#if !defined __loongarch_soft_float
+extern __typeof (REDIRECT_NAME) OPTIMIZE (lasx) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (lsx) attribute_hidden;
+#endif
+extern __typeof (REDIRECT_NAME) OPTIMIZE (aligned) attribute_hidden;
+
+static inline void *
+IFUNC_SELECTOR (void)
+{
+#if !defined __loongarch_soft_float
+  if (SUPPORT_LASX)
+    return OPTIMIZE (lasx);
+  else if (SUPPORT_LSX)
+    return OPTIMIZE (lsx);
+  else
+#endif
+    return OPTIMIZE (aligned);
+}
diff --git a/sysdeps/loongarch/lp64/multiarch/memcmp-aligned.S b/sysdeps/loongarch/lp64/multiarch/memcmp-aligned.S
new file mode 100644
index 0000000000..14a7caa9a8
--- /dev/null
+++ b/sysdeps/loongarch/lp64/multiarch/memcmp-aligned.S
@@ -0,0 +1,292 @@
+/* Optimized memcmp implementation using basic LoongArch instructions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/regdef.h>
+#include <sys/asm.h>
+
+#if IS_IN (libc)
+# define MEMCMP_NAME __memcmp_aligned
+#else
+# define MEMCMP_NAME memcmp
+#endif
+
+LEAF(MEMCMP_NAME, 6)
+    beqz        a2, L(ret)
+    andi        a4, a1, 0x7
+    andi        a3, a0, 0x7
+    sltu        a5, a4, a3
+
+    xor         t0, a0, a1
+    li.w        t8, 8
+    maskeqz     t0, t0, a5
+    li.w        t7, -1
+
+    xor         a0, a0, t0
+    xor         a1, a1, t0
+    andi        a3, a0, 0x7
+    andi        a4, a1, 0x7
+
+    xor         a0, a0, a3
+    xor         a1, a1, a4
+    ld.d        t2, a0, 0
+    ld.d        t1, a1, 0
+
+    slli.d      t3, a3, 3
+    slli.d      t4, a4, 3
+    sub.d       a6, t3, t4
+    srl.d       t1, t1, t4
+
+    srl.d       t0, t2, t3
+    srl.d       t5, t7, t4
+    sub.d       t6, t0, t1
+    and         t6, t6, t5
+
+    sub.d       t5, t8, a4
+    bnez        t6, L(first_out)
+    bgeu        t5, a2, L(ret)
+    sub.d       a2, a2, t5
+
+    bnez        a6, L(unaligned)
+    blt         a2, t8, L(al_less_8bytes)
+    andi        t1, a2, 31
+    beq         t1, a2, L(al_less_32bytes)
+
+    sub.d       t2, a2, t1
+    add.d       a4, a0, t2
+    move        a2, t1
+
+L(al_loop):
+    ld.d        t0, a0, 8
+
+    ld.d        t1, a1, 8
+    ld.d        t2, a0, 16
+    ld.d        t3, a1, 16
+    ld.d        t4, a0, 24
+
+    ld.d        t5, a1, 24
+    ld.d        t6, a0, 32
+    ld.d        t7, a1, 32
+    addi.d      a0, a0, 32
+
+    addi.d      a1, a1, 32
+    bne         t0, t1, L(out1)
+    bne         t2, t3, L(out2)
+    bne         t4, t5, L(out3)
+
+    bne         t6, t7, L(out4)
+    bne         a0, a4, L(al_loop)
+
+L(al_less_32bytes):
+    srai.d      a4, a2, 4
+    beqz        a4, L(al_less_16bytes)
+
+    ld.d        t0, a0, 8
+    ld.d        t1, a1, 8
+    ld.d        t2, a0, 16
+    ld.d        t3, a1, 16
+
+    addi.d      a0, a0, 16
+    addi.d      a1, a1, 16
+    addi.d      a2, a2, -16
+    bne         t0, t1, L(out1)
+
+    bne         t2, t3, L(out2)
+
+L(al_less_16bytes):
+    srai.d      a4, a2, 3
+    beqz        a4, L(al_less_8bytes)
+    ld.d        t0, a0, 8
+
+    ld.d        t1, a1, 8
+    addi.d      a0, a0, 8
+    addi.d      a1, a1, 8
+    addi.d      a2, a2, -8
+
+    bne         t0, t1, L(out1)
+
+L(al_less_8bytes):
+    beqz        a2, L(ret)
+    ld.d        t0, a0, 8
+    ld.d        t1, a1, 8
+
+    li.d        t7, -1
+    slli.d      t2, a2, 3
+    sll.d       t2, t7, t2
+    sub.d       t3, t0, t1
+
+    andn        t6, t3, t2
+    bnez        t6, L(count_diff)
+
+L(ret):
+    move        a0, zero
+    jr          ra
+
+L(out4):
+    move        t0, t6
+    move        t1, t7
+    sub.d       t6, t6, t7
+    b           L(count_diff)
+
+L(out3):
+    move        t0, t4
+    move        t1, t5
+    sub.d       t6, t4, t5
+    b           L(count_diff)
+
+L(out2):
+    move        t0, t2
+    move        t1, t3
+L(out1):
+    sub.d       t6, t0, t1
+    b           L(count_diff)
+
+L(first_out):
+    slli.d      t4, a2, 3
+    slt         t3, a2, t5
+    sll.d       t4, t7, t4
+    maskeqz     t4, t4, t3
+
+    andn        t6, t6, t4
+
+L(count_diff):
+    ctz.d       t2, t6
+    bstrins.d   t2, zero, 2, 0
+    srl.d       t0, t0, t2
+
+    srl.d       t1, t1, t2
+    andi        t0, t0, 0xff
+    andi        t1, t1, 0xff
+    sub.d       t2, t0, t1
+
+    sub.d       t3, t1, t0
+    masknez     t2, t2, a5
+    maskeqz     t3, t3, a5
+    or          a0, t2, t3
+
+    jr          ra
+
+L(unaligned):
+    sub.d       a7, zero, a6
+    srl.d       t0, t2, a6
+    blt         a2, t8, L(un_less_8bytes)
+
+    andi        t1, a2, 31
+    beq         t1, a2, L(un_less_32bytes)
+    sub.d       t2, a2, t1
+    add.d       a4, a0, t2
+
+    move        a2, t1
+
+L(un_loop):
+    ld.d        t2, a0, 8
+    ld.d        t1, a1, 8
+    ld.d        t4, a0, 16
+
+    ld.d        t3, a1, 16
+    ld.d        t6, a0, 24
+    ld.d        t5, a1, 24
+    ld.d        t8, a0, 32
+
+    ld.d        t7, a1, 32
+    addi.d      a0, a0, 32
+    addi.d      a1, a1, 32
+    sll.d       a3, t2, a7
+
+    or          t0, a3, t0
+    bne         t0, t1, L(out1)
+    srl.d       t0, t2, a6
+    sll.d       a3, t4, a7
+
+    or          t2, a3, t0
+    bne         t2, t3, L(out2)
+    srl.d       t0, t4, a6
+    sll.d       a3, t6, a7
+
+    or          t4, a3, t0
+    bne         t4, t5, L(out3)
+    srl.d       t0, t6, a6
+    sll.d       a3, t8, a7
+
+    or          t6, t0, a3
+    bne         t6, t7, L(out4)
+    srl.d       t0, t8, a6
+    bne         a0, a4, L(un_loop)
+
+L(un_less_32bytes):
+    srai.d      a4, a2, 4
+    beqz        a4, L(un_less_16bytes)
+    ld.d        t2, a0, 8
+    ld.d        t1, a1, 8
+
+    ld.d        t4, a0, 16
+    ld.d        t3, a1, 16
+    addi.d      a0, a0, 16
+    addi.d      a1, a1, 16
+
+    addi.d      a2, a2, -16
+    sll.d       a3, t2, a7
+    or          t0, a3, t0
+    bne         t0, t1, L(out1)
+
+    srl.d       t0, t2, a6
+    sll.d       a3, t4, a7
+    or          t2, a3, t0
+    bne         t2, t3, L(out2)
+
+    srl.d       t0, t4, a6
+
+L(un_less_16bytes):
+    srai.d      a4, a2, 3
+    beqz        a4, L(un_less_8bytes)
+    ld.d        t2, a0, 8
+
+    ld.d        t1, a1, 8
+    addi.d      a0, a0, 8
+    addi.d      a1, a1, 8
+    addi.d      a2, a2, -8
+
+    sll.d       a3, t2, a7
+    or          t0, a3, t0
+    bne         t0, t1, L(out1)
+    srl.d       t0, t2, a6
+
+L(un_less_8bytes):
+    beqz        a2, L(ret)
+    andi        a7, a7, 63
+    slli.d      a4, a2, 3
+    bgeu        a7, a4, L(last_cmp)
+
+    ld.d        t2, a0, 8
+    sll.d       a3, t2, a7
+    or          t0, a3, t0
+
+L(last_cmp):
+    ld.d        t1, a1, 8
+
+    li.d        t7, -1
+    sll.d       t2, t7, a4
+    sub.d       t3, t0, t1
+    andn        t6, t3, t2
+
+    bnez        t6, L(count_diff)
+    move        a0, zero
+    jr          ra
+END(MEMCMP_NAME)
+
+libc_hidden_builtin_def (MEMCMP_NAME)
diff --git a/sysdeps/loongarch/lp64/multiarch/memcmp-lasx.S b/sysdeps/loongarch/lp64/multiarch/memcmp-lasx.S
new file mode 100644
index 0000000000..3151a17927
--- /dev/null
+++ b/sysdeps/loongarch/lp64/multiarch/memcmp-lasx.S
@@ -0,0 +1,207 @@
+/* Optimized memcmp implementation using LoongArch LASX instructions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/regdef.h>
+#include <sys/asm.h>
+
+#if IS_IN (libc) && !defined __loongarch_soft_float
+
+# define MEMCMP __memcmp_lasx
+
+LEAF(MEMCMP, 6)
+    li.d            t2, 32
+    add.d           a3, a0, a2
+    add.d           a4, a1, a2
+    bgeu            t2, a2, L(less32)
+
+    li.d            t1, 160
+    bgeu            a2, t1, L(make_aligned)
+L(loop32):
+    xvld            xr0, a0, 0
+    xvld            xr1, a1, 0
+
+    addi.d          a0, a0, 32
+    addi.d          a1, a1, 32
+    addi.d          a2, a2, -32
+    xvseq.b         xr2, xr0, xr1
+
+    xvsetanyeqz.b   fcc0, xr2
+    bcnez           fcc0, L(end)
+L(last_bytes):
+    bltu            t2, a2, L(loop32)
+    xvld            xr0, a3, -32
+
+
+    xvld            xr1, a4, -32
+    xvseq.b         xr2, xr0, xr1
+L(end):
+    xvmsknz.b       xr2, xr2
+    xvpermi.q       xr4, xr0, 1
+
+    xvpickve.w      xr3, xr2, 4
+    xvpermi.q       xr5, xr1, 1
+    vilvl.h         vr2, vr3, vr2
+    movfr2gr.s      t0, fa2
+
+    cto.w           t0, t0
+    vreplgr2vr.b    vr2, t0
+    vshuf.b         vr0, vr4, vr0, vr2
+    vshuf.b         vr1, vr5, vr1, vr2
+
+    vpickve2gr.bu   t0, vr0, 0
+    vpickve2gr.bu   t1, vr1, 0
+    sub.d           a0, t0, t1
+    jr              ra
+
+
+L(less32):
+    srli.d          t0, a2, 4
+    beqz            t0, L(less16)
+    vld             vr0, a0, 0
+    vld             vr1, a1, 0
+
+    vld             vr2, a3, -16
+    vld             vr3, a4, -16
+L(short_ret):
+    vseq.b          vr4, vr0, vr1
+    vseq.b          vr5, vr2, vr3
+
+    vmsknz.b        vr4, vr4
+    vmsknz.b        vr5, vr5
+    vilvl.h         vr4, vr5, vr4
+    movfr2gr.s      t0, fa4
+
+    cto.w           t0, t0
+    vreplgr2vr.b    vr4, t0
+    vshuf.b         vr0, vr2, vr0, vr4
+    vshuf.b         vr1, vr3, vr1, vr4
+
+
+    vpickve2gr.bu   t0, vr0, 0
+    vpickve2gr.bu   t1, vr1, 0
+    sub.d           a0, t0, t1
+    jr              ra
+
+L(less16):
+    srli.d          t0, a2, 3
+    beqz            t0, L(less8)
+    vldrepl.d       vr0, a0, 0
+    vldrepl.d       vr1, a1, 0
+
+    vldrepl.d       vr2, a3, -8
+    vldrepl.d       vr3, a4, -8
+    b               L(short_ret)
+    nop
+
+L(less8):
+    srli.d          t0, a2, 2
+    beqz            t0, L(less4)
+    vldrepl.w       vr0, a0, 0
+    vldrepl.w       vr1, a1, 0
+
+
+    vldrepl.w       vr2, a3, -4
+    vldrepl.w       vr3, a4, -4
+    b               L(short_ret)
+    nop
+
+L(less4):
+    srli.d          t0, a2, 1
+    beqz            t0, L(less2)
+    vldrepl.h       vr0, a0, 0
+    vldrepl.h       vr1, a1, 0
+
+    vldrepl.h       vr2, a3, -2
+    vldrepl.h       vr3, a4, -2
+    b               L(short_ret)
+    nop
+
+L(less2):
+    beqz            a2, L(ret0)
+    ld.bu           t0, a0, 0
+    ld.bu           t1, a1, 0
+    sub.d           a0, t0, t1
+
+    jr              ra
+L(ret0):
+    move            a0, zero
+    jr              ra
+
+L(make_aligned):
+    xvld            xr0, a0, 0
+
+    xvld            xr1, a1, 0
+    xvseq.b         xr2, xr0, xr1
+    xvsetanyeqz.b   fcc0, xr2
+    bcnez           fcc0, L(end)
+
+    andi            t0, a0, 0x1f
+    sub.d           t0, t2, t0
+    sub.d           t1, a2, t0
+    add.d           a0, a0, t0
+
+    add.d           a1, a1, t0
+    andi            a2, t1, 0x3f
+    sub.d           t0, t1, a2
+    add.d           a5, a0, t0
+
+
+L(loop_align):
+    xvld            xr0, a0, 0
+    xvld            xr1, a1, 0
+    xvld            xr2, a0, 32
+    xvld            xr3, a1, 32
+
+    xvseq.b         xr0, xr0, xr1
+    xvseq.b         xr1, xr2, xr3
+    xvmin.bu        xr2, xr1, xr0
+    xvsetanyeqz.b   fcc0, xr2
+
+    bcnez           fcc0, L(pair_end)
+    addi.d          a0, a0, 64
+    addi.d          a1, a1, 64
+    bne             a0, a5, L(loop_align)
+
+    bnez            a2, L(last_bytes)
+    move            a0, zero
+    jr              ra
+    nop
+
+
+L(pair_end):
+    xvmsknz.b       xr0, xr0
+    xvmsknz.b       xr1, xr1
+    xvpickve.w      xr2, xr0, 4
+    xvpickve.w      xr3, xr1, 4
+
+    vilvl.h         vr0, vr2, vr0
+    vilvl.h         vr1, vr3, vr1
+    vilvl.w         vr0, vr1, vr0
+    movfr2gr.d      t0, fa0
+
+    cto.d           t0, t0
+    ldx.bu          t1, a0, t0
+    ldx.bu          t2, a1, t0
+    sub.d           a0, t1, t2
+
+    jr              ra
+END(MEMCMP)
+
+libc_hidden_builtin_def (MEMCMP)
+#endif
diff --git a/sysdeps/loongarch/lp64/multiarch/memcmp-lsx.S b/sysdeps/loongarch/lp64/multiarch/memcmp-lsx.S
new file mode 100644
index 0000000000..38a50a4c16
--- /dev/null
+++ b/sysdeps/loongarch/lp64/multiarch/memcmp-lsx.S
@@ -0,0 +1,269 @@
+/* Optimized memcmp implementation using LoongArch LSX instructions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/regdef.h>
+#include <sys/asm.h>
+
+#if IS_IN (libc) && !defined __loongarch_soft_float
+
+#define MEMCMP __memcmp_lsx
+
+LEAF(MEMCMP, 6)
+    beqz            a2, L(out)
+    pcalau12i       t0, %pc_hi20(L(INDEX))
+    andi            a3, a0, 0xf
+    vld             vr5, t0, %pc_lo12(L(INDEX))
+
+    andi            a4, a1, 0xf
+    bne             a3, a4, L(unaligned)
+    bstrins.d       a0, zero, 3, 0
+    xor             a1, a1, a4
+
+    vld             vr0, a0, 0
+    vld             vr1, a1, 0
+    li.d            t0, 16
+    vreplgr2vr.b    vr3, a3
+
+    sub.d           t1, t0, a3
+    vadd.b          vr3, vr3, vr5
+    vshuf.b         vr0, vr3, vr0, vr3
+    vshuf.b         vr1, vr3, vr1, vr3
+
+
+    vseq.b          vr4, vr0, vr1
+    bgeu            t1, a2, L(al_end)
+    vsetanyeqz.b    fcc0, vr4
+    bcnez           fcc0, L(al_found)
+
+    sub.d           t1, a2, t1
+    andi            a2, t1, 31
+    beq             a2, t1, L(al_less_32bytes)
+    sub.d           t2, t1, a2
+
+    add.d           a4, a0, t2
+L(al_loop):
+    vld             vr0, a0, 16
+    vld             vr1, a1, 16
+    vld             vr2, a0, 32
+
+    vld             vr3, a1, 32
+    addi.d          a0, a0, 32
+    addi.d          a1, a1, 32
+    vseq.b          vr4, vr0, vr1
+
+
+    vseq.b          vr6, vr2, vr3
+    vand.v          vr6, vr4, vr6
+    vsetanyeqz.b    fcc0, vr6
+    bcnez           fcc0, L(al_pair_end)
+
+    bne             a0, a4, L(al_loop)
+L(al_less_32bytes):
+    bgeu            t0, a2, L(al_less_16bytes)
+    vld             vr0, a0, 16
+    vld             vr1, a1, 16
+
+    vld             vr2, a0, 32
+    vld             vr3, a1, 32
+    addi.d          a2, a2, -16
+    vreplgr2vr.b    vr6, a2
+
+    vslt.b          vr5, vr5, vr6
+    vseq.b          vr4, vr0, vr1
+    vseq.b          vr6, vr2, vr3
+    vorn.v          vr6, vr6, vr5
+
+
+L(al_pair_end):
+    vsetanyeqz.b    fcc0, vr4
+    bcnez           fcc0, L(al_found)
+    vnori.b         vr4, vr6, 0
+    vfrstpi.b       vr4, vr4, 0
+
+    vshuf.b         vr0, vr2, vr2, vr4
+    vshuf.b         vr1, vr3, vr3, vr4
+    vpickve2gr.bu   t0, vr0, 0
+    vpickve2gr.bu   t1, vr1, 0
+
+    sub.d           a0, t0, t1
+    jr              ra
+    nop
+    nop
+
+L(al_less_16bytes):
+    beqz            a2, L(out)
+    vld             vr0, a0, 16
+    vld             vr1, a1, 16
+    vseq.b          vr4, vr0, vr1
+
+
+L(al_end):
+    vreplgr2vr.b    vr6, a2
+    vslt.b          vr5, vr5, vr6
+    vorn.v          vr4, vr4, vr5
+    nop
+
+L(al_found):
+    vnori.b         vr4, vr4, 0
+    vfrstpi.b       vr4, vr4, 0
+    vshuf.b         vr0, vr0, vr0, vr4
+    vshuf.b         vr1, vr1, vr1, vr4
+
+    vpickve2gr.bu   t0, vr0, 0
+    vpickve2gr.bu   t1, vr1, 0
+    sub.d           a0, t0, t1
+    jr              ra
+
+L(out):
+    move            a0, zero
+    jr              ra
+    nop
+    nop
+
+
+L(unaligned):
+    xor             t2, a0, a1
+    sltu            a5, a3, a4
+    masknez         t2, t2, a5
+    xor             a0, a0, t2
+
+    xor             a1, a1, t2
+    andi            a3, a0, 0xf
+    andi            a4, a1, 0xf
+    bstrins.d       a0, zero, 3, 0
+
+    xor             a1, a1, a4
+    vld             vr4, a0, 0
+    vld             vr1, a1, 0
+    li.d            t0, 16
+
+    vreplgr2vr.b    vr2, a4
+    sub.d           a6, a4, a3
+    sub.d           t1, t0, a4
+    sub.d           t2, t0, a6
+
+
+    vadd.b          vr2, vr2, vr5
+    vreplgr2vr.b    vr6, t2
+    vadd.b          vr6, vr6, vr5
+    vshuf.b         vr0, vr4, vr4, vr6
+
+    vshuf.b         vr1, vr2, vr1, vr2
+    vshuf.b         vr0, vr2, vr0, vr2
+    vseq.b          vr7, vr0, vr1
+    bgeu            t1, a2, L(un_end)
+
+    vsetanyeqz.b    fcc0, vr7
+    bcnez           fcc0, L(un_found)
+    sub.d           a2, a2, t1
+    andi            t1, a2, 31
+
+    beq             a2, t1, L(un_less_32bytes)
+    sub.d           t2, a2, t1
+    move            a2, t1
+    add.d           a4, a1, t2
+
+
+L(un_loop):
+    vld             vr2, a0, 16
+    vld             vr1, a1, 16
+    vld             vr3, a1, 32
+    addi.d          a1, a1, 32
+
+    addi.d          a0, a0, 32
+    vshuf.b         vr0, vr2, vr4, vr6
+    vld             vr4, a0, 0
+    vseq.b          vr7, vr0, vr1
+
+    vshuf.b         vr2, vr4, vr2, vr6
+    vseq.b          vr8, vr2, vr3
+    vand.v          vr8, vr7, vr8
+    vsetanyeqz.b    fcc0, vr8
+
+    bcnez           fcc0, L(un_pair_end)
+    bne             a1, a4, L(un_loop)
+
+L(un_less_32bytes):
+    bltu            a2, t0, L(un_less_16bytes)
+    vld             vr2, a0, 16
+    vld             vr1, a1, 16
+    addi.d          a0, a0, 16
+
+    addi.d          a1, a1, 16
+    addi.d          a2, a2, -16
+    vshuf.b         vr0, vr2, vr4, vr6
+    vor.v           vr4, vr2, vr2
+
+    vseq.b          vr7, vr0, vr1
+    vsetanyeqz.b    fcc0, vr7
+    bcnez           fcc0, L(un_found)
+L(un_less_16bytes):
+    beqz            a2, L(out)
+    vld             vr1, a1, 16
+    bgeu            a6, a2, 1f
+
+    vld             vr2, a0, 16
+1:
+    vshuf.b         vr0, vr2, vr4, vr6
+    vseq.b          vr7, vr0, vr1
+L(un_end):
+    vreplgr2vr.b    vr3, a2
+
+
+    vslt.b          vr3, vr5, vr3
+    vorn.v          vr7, vr7, vr3
+
+L(un_found):
+    vnori.b         vr7, vr7, 0
+    vfrstpi.b       vr7, vr7, 0
+
+    vshuf.b         vr0, vr0, vr0, vr7
+    vshuf.b         vr1, vr1, vr1, vr7
+L(calc_result):
+    vpickve2gr.bu   t0, vr0, 0
+    vpickve2gr.bu   t1, vr1, 0
+
+    sub.d           t2, t0, t1
+    sub.d           t3, t1, t0
+    masknez         t0, t3, a5
+    maskeqz         t1, t2, a5
+
+    or              a0, t0, t1
+    jr              ra
+L(un_pair_end):
+    vsetanyeqz.b    fcc0, vr7
+    bcnez           fcc0, L(un_found)
+
+
+    vnori.b         vr7, vr8, 0
+    vfrstpi.b       vr7, vr7, 0
+    vshuf.b         vr0, vr2, vr2, vr7
+    vshuf.b         vr1, vr3, vr3, vr7
+
+    b               L(calc_result)
+END(MEMCMP)
+
+    .section         .rodata.cst16,"M",@progbits,16
+    .align           4
+L(INDEX):
+    .dword           0x0706050403020100
+    .dword           0x0f0e0d0c0b0a0908
+
+libc_hidden_builtin_def (MEMCMP)
+#endif
diff --git a/sysdeps/loongarch/lp64/multiarch/memcmp.c b/sysdeps/loongarch/lp64/multiarch/memcmp.c
new file mode 100644
index 0000000000..32eccac2a3
--- /dev/null
+++ b/sysdeps/loongarch/lp64/multiarch/memcmp.c
@@ -0,0 +1,43 @@
+/* Multiple versions of memcmp.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Define multiple versions only for the definition in libc.  */
+#if IS_IN (libc)
+# define memcmp __redirect_memcmp
+# include <string.h>
+# undef memcmp
+
+# define SYMBOL_NAME memcmp
+# include "ifunc-memcmp.h"
+
+libc_ifunc_redirected (__redirect_memcmp, memcmp,
+		       IFUNC_SELECTOR ());
+# undef bcmp
+weak_alias (memcmp, bcmp)
+
+# undef __memcmpeq
+strong_alias (memcmp, __memcmpeq)
+libc_hidden_def (__memcmpeq)
+
+# ifdef SHARED
+__hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp)
+  __attribute__ ((visibility ("hidden"))) __attribute_copy__ (memcmp);
+# endif
+
+#endif