diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index 99c414cc910..7faffb55046 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -39,9 +39,11 @@
 #include "emit-rtl.h"
 #include "tm_p.h"
 #include "target.h"
+#include "targhooks.h"
 #include "expr.h"
 #include "optabs.h"
 #include "tm-constrs.h"
+#include "riscv-vector-builtins.h"
 #include "rtx-vector-builder.h"
 
 using namespace riscv_vector;
@@ -176,6 +178,56 @@ calculate_ratio (unsigned int sew, enum vlmul_type vlmul)
   return ratio;
 }
 
+/* SCALABLE means that the vector-length is agnostic (run-time invariant and
+   compile-time unknown). FIXED meands that the vector-length is specific
+   (compile-time known). Both RVV_SCALABLE and RVV_FIXED_VLMAX are doing
+   auto-vectorization using VLMAX vsetvl configuration.  */
+static bool
+autovec_use_vlmax_p (void)
+{
+  return riscv_autovec_preference == RVV_SCALABLE
+	 || riscv_autovec_preference == RVV_FIXED_VLMAX;
+}
+
+/* Return the vectorization machine mode for RVV according to LMUL.  */
+machine_mode
+riscv_vector_preferred_simd_mode (scalar_mode mode)
+{
+  /* We only enable auto-vectorization when TARGET_MIN_VLEN >= 128 &&
+     riscv_autovec_lmul < RVV_M2. Since GCC loop vectorizer report ICE
+     when we enable -march=rv64gc_zve32* and -march=rv32gc_zve64*.
+     in the 'can_duplicate_and_interleave_p' of tree-vect-slp.cc. Since we have
+     VNx1SImode in -march=*zve32* and VNx1DImode in -march=*zve64*, they are
+     enabled in targetm. vector_mode_supported_p and SLP vectorizer will try to
+     use them. Currently, we can support auto-vectorization in
+     -march=rv32_zve32x_zvl128b. Wheras, -march=rv32_zve32x_zvl32b or
+     -march=rv32_zve32x_zvl64b are disabled.
+ */
+  if (autovec_use_vlmax_p ())
+    {
+      /* If TARGET_MIN_VLEN < 128, we don't allow LMUL < 2
+	 auto-vectorization since Loop Vectorizer may use VNx1SImode or
+	 VNx1DImode to vectorize which will create ICE in the
+	 'can_duplicate_and_interleave_p' of tree-vect-slp.cc.  */
+      if (TARGET_MIN_VLEN < 128 && riscv_autovec_lmul < RVV_M2)
+	return word_mode;
+      /* We use LMUL = 1 as base bytesize which is BYTES_PER_RISCV_VECTOR and
+	 riscv_autovec_lmul as multiply factor to calculate the the NUNITS to
+	 get the auto-vectorization mode.  */
+      poly_uint64 nunits;
+      poly_uint64 vector_size
+	= BYTES_PER_RISCV_VECTOR * ((int) riscv_autovec_lmul);
+      poly_uint64 scalar_size = GET_MODE_SIZE (mode);
+      gcc_assert (multiple_p (vector_size, scalar_size, &nunits));
+      machine_mode rvv_mode;
+      if (get_vector_mode (mode, nunits).exists (&rvv_mode))
+	return rvv_mode;
+    }
+  /* TODO: We will support minimum length VLS auto-vectorization in the future.
+   */
+  return word_mode;
+}
+
 /* Emit an RVV unmask && vl mov from SRC to DEST.  */
 static void
 emit_pred_op (unsigned icode, rtx mask, rtx dest, rtx src, rtx len,
@@ -430,6 +482,45 @@ get_avl_type_rtx (enum avl_type type)
   return gen_int_mode (type, Pmode);
 }
 
+/* Return the mask policy for no predication.  */
+rtx
+get_mask_policy_no_pred ()
+{
+  return get_mask_policy_for_pred (PRED_TYPE_none);
+}
+
+/* Return the tail policy for no predication.  */
+rtx
+get_tail_policy_no_pred ()
+{
+  return get_tail_policy_for_pred (PRED_TYPE_none);
+}
+
+/* Return true if it is a RVV mask mode.  */
+bool
+riscv_vector_mask_mode_p (machine_mode mode)
+{
+  return (mode == VNx1BImode || mode == VNx2BImode || mode == VNx4BImode
+	  || mode == VNx8BImode || mode == VNx16BImode || mode == VNx32BImode
+	  || mode == VNx64BImode);
+}
+
+/* Return the appropriate mask mode for MODE.  */
+
+opt_machine_mode
+riscv_vector_get_mask_mode (machine_mode mode)
+{
+  machine_mode mask_mode;
+  int nf = 1;
+
+  FOR_EACH_MODE_IN_CLASS (mask_mode, MODE_VECTOR_BOOL)
+  if (GET_MODE_INNER (mask_mode) == BImode
+      && known_eq (GET_MODE_NUNITS (mask_mode) * nf, GET_MODE_NUNITS (mode))
+      && riscv_vector_mask_mode_p (mask_mode))
+    return mask_mode;
+  return default_get_mask_mode (mode);
+}
+
 /* Return the RVV vector mode that has NUNITS elements of mode INNER_MODE.
    This function is not only used by builtins, but also will be used by
    auto-vectorization in the future.  */
