[PATCH] RISC-V: Enable VECT_COMPARE_COSTS by default

[Juzhe-Zhong]

since we have added COST framework, we by default enable VECT_COMPARE_COSTS.

Also, add 16/32/64 to provide more choices for COST comparison.

This patch doesn't change any behavior from the current testsuite since we are 
using
default COST model.

gcc/ChangeLog:

        * config/riscv/riscv-v.cc (autovectorize_vector_modes): Enable 
VECT_COMPARE_COSTS by default.

---
 gcc/config/riscv/riscv-v.cc | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index 6228ff3d92e..c8ad96f44d5 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -2173,7 +2173,7 @@ autovectorize_vector_modes (vector_modes *modes, bool)
           full vectors for wider elements.
         - full_size / 8:
           Try using 64-bit containers for all element types.  */
-      static const int rvv_factors[] = {1, 2, 4, 8};
+      static const int rvv_factors[] = {1, 2, 4, 8, 16, 32, 64};
       for (unsigned int i = 0; i < sizeof (rvv_factors) / sizeof (int); i++)
        {
          poly_uint64 units;
@@ -2183,12 +2183,8 @@ autovectorize_vector_modes (vector_modes *modes, bool)
            modes->safe_push (mode);
        }
     }
-  unsigned int flag = 0;
   if (TARGET_VECTOR_VLS)
     {
-      /* Enable VECT_COMPARE_COSTS between VLA modes VLS modes for scalable
-        auto-vectorization.  */
-      flag |= VECT_COMPARE_COSTS;
       /* Push all VLSmodes according to TARGET_MIN_VLEN.  */
       unsigned int i = 0;
       unsigned int base_size = TARGET_MIN_VLEN * riscv_autovec_lmul / 8;
@@ -2201,7 +2197,8 @@ autovectorize_vector_modes (vector_modes *modes, bool)
          size = base_size / (1U << i);
        }
     }
-  return flag;
+  /* Enable LOOP_VINFO comparison in COST model.  */
+  return VECT_COMPARE_COSTS;
 }
 
 /* If the given VECTOR_MODE is an RVV mode,  first get the largest number
-- 
2.36.3