RISC-V: Some minior tweak on dynamic LMUL cost model

Tweak some codes of dynamic LMUL cost model to make computation more predictable and accurate.

Tested on both RV32 and RV64 no regression.

Committed.

	PR target/113112

gcc/ChangeLog:

	* config/riscv/riscv-vector-costs.cc (compute_estimated_lmul): Tweak LMUL estimation.
	(has_unexpected_spills_p): Ditto.
	(costs::record_potential_unexpected_spills): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-1.c: Add more checks.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-2.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-3.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-4.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-5.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-6.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul1-7.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-1.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-2.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-3.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-4.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul2-5.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-1.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-2.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-3.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-5.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-6.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-7.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul4-8.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-1.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-10.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-11.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-2.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-3.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-4.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-5.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-6.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-7.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-8.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-9.c: Ditto.
	* gcc.dg/vect/costmodel/riscv/rvv/dynamic-lmul8-12.c: New test.
	* gcc.dg/vect/costmodel/riscv/rvv/pr113112-2.c: New test.

1 files changed, 29 insertions, 13 deletions

diff --git a/gcc/config/riscv/riscv-vector-costs.cc b/gcc/config/riscv/riscv-vector-costs.cc
index 7b837b0..74b8e86 100644
--- a/gcc/config/riscv/riscv-vector-costs.cc
+++ b/gcc/config/riscv/riscv-vector-costs.cc
@@ -394,21 +394,32 @@ compute_estimated_lmul (loop_vec_info loop_vinfo, machine_mode mode)
 {
   gcc_assert (GET_MODE_BITSIZE (mode).is_constant ());
   int regno_alignment = riscv_get_v_regno_alignment (loop_vinfo->vector_mode);
-  if (known_eq (LOOP_VINFO_SLP_UNROLLING_FACTOR (loop_vinfo), 1U))
+  if (riscv_v_ext_vls_mode_p (loop_vinfo->vector_mode))
+    return regno_alignment;
+  else if (known_eq (LOOP_VINFO_SLP_UNROLLING_FACTOR (loop_vinfo), 1U)
+	   || LOOP_VINFO_SLP_UNROLLING_FACTOR (loop_vinfo).is_constant ())
     {
       int estimated_vf = vect_vf_for_cost (loop_vinfo);
       return estimated_vf * GET_MODE_BITSIZE (mode).to_constant ()
 	     / TARGET_MIN_VLEN;
     }
-  else if (regno_alignment > 1)
-    return regno_alignment;
   else
     {
-      int ratio;
-      if (can_div_trunc_p (BYTES_PER_RISCV_VECTOR,
-			   LOOP_VINFO_SLP_UNROLLING_FACTOR (loop_vinfo),
-			   &ratio))
-	return TARGET_MAX_LMUL / ratio;
+      /* Estimate the VLA SLP LMUL.  */
+      if (regno_alignment > RVV_M1)
+	return regno_alignment;
+      else if (mode != QImode)
+	{
+	  int ratio;
+	  if (can_div_trunc_p (BYTES_PER_RISCV_VECTOR,
+			       GET_MODE_SIZE (loop_vinfo->vector_mode), &ratio))
+	    {
+	      if (ratio == 1)
+		return RVV_M4;
+	      else if (ratio == 2)
+		return RVV_M2;
+	    }
+	}
     }
   return 0;
 }
@@ -540,7 +551,10 @@ update_local_live_ranges (
 	  stmt_vec_info stmt_info = vinfo->lookup_stmt (gsi_stmt (si));
 	  enum stmt_vec_info_type type
 	    = STMT_VINFO_TYPE (vect_stmt_to_vectorize (stmt_info));
-	  if (non_contiguous_memory_access_p (stmt_info))
+	  if (non_contiguous_memory_access_p (stmt_info)
+	      /* LOAD_LANES/STORE_LANES doesn't need a perm indice.  */
+	      && STMT_VINFO_MEMORY_ACCESS_TYPE (stmt_info)
+		   != VMAT_LOAD_STORE_LANES)
 	    {
 	      /* For non-adjacent load/store STMT, we will potentially
 		 convert it into:
@@ -578,9 +592,6 @@ update_local_live_ranges (
 static bool
 has_unexpected_spills_p (loop_vec_info loop_vinfo)
 {
-  /* We don't apply dynamic LMUL cost model on VLS modes.  */
-  if (!riscv_v_ext_vector_mode_p (loop_vinfo->vector_mode))
-    return false;
   /* Compute local program points.
      It's a fast and effective computation.  */
   hash_map<basic_block, vec<stmt_point>> program_points_per_bb;
@@ -682,7 +693,12 @@ costs::analyze_loop_vinfo (loop_vec_info loop_vinfo)
 void
 costs::record_potential_unexpected_spills (loop_vec_info loop_vinfo)
 {
-  if (riscv_autovec_lmul == RVV_DYNAMIC)
+  /* We only want to apply the heuristic if LOOP_VINFO is being
+     vectorized for VLA and known NITERS VLS loop.  */
+  if (riscv_autovec_lmul == RVV_DYNAMIC
+      && (m_cost_type == VLA_VECTOR_COST
+	  || (m_cost_type == VLS_VECTOR_COST
+	      && LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))))
     {
       bool post_dom_available_p = dom_info_available_p (CDI_POST_DOMINATORS);
       if (!post_dom_available_p)