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* [PATCH] RISC-V: Switch RVV cost model to generic vector cost model
@ 2024-01-10  9:58 Juzhe-Zhong
  2024-01-10 14:11 ` Robin Dapp
  0 siblings, 1 reply; 8+ messages in thread
From: Juzhe-Zhong @ 2024-01-10  9:58 UTC (permalink / raw)
  To: gcc-patches; +Cc: kito.cheng, kito.cheng, jeffreyalaw, rdapp.gcc, Juzhe-Zhong

This patch is preparing patch for the following cost model tweak.

Since we don't have vector cost model in default tune info (rocket),
we set the cost model default as generic cost model by default.

The reason we want to switch to generic vector cost model is the default
cost model generates inferior codegen for various benchmarks.

For example, PR113247, we have performance bug that we end up having over 70%
performance drop of SHA256.  Currently, no matter how we adapt cost model,
we are not able to fix the performance bug since we always use default cost model by default.

Also, tweak the generic cost model back to default cost model since we have some FAILs in
current tests.

After this patch, we (me an Robin) can work on cost model tunning together to improve performane
in various benchmarks.

Tested on both RV32 and RV64, ok for trunk ?

gcc/ChangeLog:

	* config/riscv/riscv.cc (get_common_costs): Switch RVV cost model.
	(get_vector_costs): Ditto.
	(riscv_builtin_vectorization_cost): Ditto.

---
 gcc/config/riscv/riscv.cc | 117 ++++++++++++++++++++------------------
 1 file changed, 61 insertions(+), 56 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 32183d63180..d72058039ce 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -358,13 +358,13 @@ static const common_vector_cost generic_vls_vector_cost = {
   1, /* fp_stmt_cost  */
   1, /* gather_load_cost  */
   1, /* scatter_store_cost  */
-  2, /* vec_to_scalar_cost  */
+  1, /* vec_to_scalar_cost  */
   1, /* scalar_to_vec_cost  */
-  2, /* permute_cost  */
+  1, /* permute_cost  */
   1, /* align_load_cost  */
   1, /* align_store_cost  */
-  1, /* unalign_load_cost  */
-  1, /* unalign_store_cost  */
+  2, /* unalign_load_cost  */
+  2, /* unalign_store_cost  */
 };
 
 /* Generic costs for VLA vector operations.  */
@@ -374,13 +374,13 @@ static const scalable_vector_cost generic_vla_vector_cost = {
     1, /* fp_stmt_cost  */
     1, /* gather_load_cost  */
     1, /* scatter_store_cost  */
-    2, /* vec_to_scalar_cost  */
+    1, /* vec_to_scalar_cost  */
     1, /* scalar_to_vec_cost  */
-    2, /* permute_cost  */
+    1, /* permute_cost  */
     1, /* align_load_cost  */
     1, /* align_store_cost  */
-    1, /* unalign_load_cost  */
-    1, /* unalign_store_cost  */
+    2, /* unalign_load_cost  */
+    2, /* unalign_store_cost  */
   },
 };
 
@@ -10372,11 +10372,10 @@ riscv_frame_pointer_required (void)
   return riscv_save_frame_pointer && !crtl->is_leaf;
 }
 
-/* Return the appropriate common costs for vectors of type VECTYPE.  */
+/* Return the appropriate common costs according to VECTYPE from COSTS.  */
 static const common_vector_cost *
-get_common_costs (tree vectype)
+get_common_costs (const cpu_vector_cost *costs, tree vectype)
 {
-  const cpu_vector_cost *costs = tune_param->vec_costs;
   gcc_assert (costs);
 
   if (vectype && riscv_v_ext_vls_mode_p (TYPE_MODE (vectype)))
@@ -10384,78 +10383,84 @@ get_common_costs (tree vectype)
   return costs->vla;
 }
 
+/* Return the CPU vector costs according to -mtune if tune info has non-NULL
+   vector cost.  Otherwide, return the default generic vector costs.  */
+static const cpu_vector_cost *
+get_vector_costs ()
+{
+  const cpu_vector_cost *costs = tune_param->vec_costs;
+  if (!costs)
+    return &generic_vector_cost;
+  return costs;
+}
+
 /* Implement targetm.vectorize.builtin_vectorization_cost.  */
 
 static int
 riscv_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 				  tree vectype, int misalign ATTRIBUTE_UNUSED)
 {
-  unsigned elements;
-  const cpu_vector_cost *costs = tune_param->vec_costs;
+  const cpu_vector_cost *costs = get_vector_costs ();
   bool fp = false;
 
   if (vectype != NULL)
     fp = FLOAT_TYPE_P (vectype);
 
-  if (costs != NULL)
+  const common_vector_cost *common_costs = get_common_costs (costs, vectype);
+  gcc_assert (common_costs != NULL);
+  switch (type_of_cost)
     {
-      const common_vector_cost *common_costs = get_common_costs (vectype);
-      gcc_assert (common_costs != NULL);
-      switch (type_of_cost)
-	{
-	case scalar_stmt:
-	  return fp ? costs->scalar_fp_stmt_cost : costs->scalar_int_stmt_cost;
+    case scalar_stmt:
+      return fp ? costs->scalar_fp_stmt_cost : costs->scalar_int_stmt_cost;
 
-	case scalar_load:
-	  return costs->scalar_load_cost;
+    case scalar_load:
+      return costs->scalar_load_cost;
 
-	case scalar_store:
-	  return costs->scalar_store_cost;
+    case scalar_store:
+      return costs->scalar_store_cost;
 
-	case vector_stmt:
-	  return fp ? common_costs->fp_stmt_cost : common_costs->int_stmt_cost;
+    case vector_stmt:
+      return fp ? common_costs->fp_stmt_cost : common_costs->int_stmt_cost;
 
-	case vector_load:
-	  return common_costs->align_load_cost;
+    case vector_load:
+      return common_costs->align_load_cost;
 
-	case vector_store:
-	  return common_costs->align_store_cost;
+    case vector_store:
+      return common_costs->align_store_cost;
 
-	case vec_to_scalar:
-	  return common_costs->vec_to_scalar_cost;
+    case vec_to_scalar:
+      return common_costs->vec_to_scalar_cost;
 
-	case scalar_to_vec:
-	  return common_costs->scalar_to_vec_cost;
+    case scalar_to_vec:
+      return common_costs->scalar_to_vec_cost;
 
-	case unaligned_load:
-	  return common_costs->unalign_load_cost;
-	case vector_gather_load:
-	  return common_costs->gather_load_cost;
+    case unaligned_load:
+      return common_costs->unalign_load_cost;
+    case vector_gather_load:
+      return common_costs->gather_load_cost;
 
-	case unaligned_store:
-	  return common_costs->unalign_store_cost;
-	case vector_scatter_store:
-	  return common_costs->scatter_store_cost;
+    case unaligned_store:
+      return common_costs->unalign_store_cost;
+    case vector_scatter_store:
+      return common_costs->scatter_store_cost;
 
-	case cond_branch_taken:
-	  return costs->cond_taken_branch_cost;
+    case cond_branch_taken:
+      return costs->cond_taken_branch_cost;
 
-	case cond_branch_not_taken:
-	  return costs->cond_not_taken_branch_cost;
+    case cond_branch_not_taken:
+      return costs->cond_not_taken_branch_cost;
 
-	case vec_perm:
-	  return common_costs->permute_cost;
+    case vec_perm:
+      return common_costs->permute_cost;
 
-	case vec_promote_demote:
-	  return fp ? common_costs->fp_stmt_cost : common_costs->int_stmt_cost;
+    case vec_promote_demote:
+      return fp ? common_costs->fp_stmt_cost : common_costs->int_stmt_cost;
 
-	case vec_construct:
-	  elements = estimated_poly_value (TYPE_VECTOR_SUBPARTS (vectype));
-	  return elements / 2 + 1;
+    case vec_construct:
+      return estimated_poly_value (TYPE_VECTOR_SUBPARTS (vectype)) - 1;
 
-	default:
-	  gcc_unreachable ();
-	}
+    default:
+      gcc_unreachable ();
     }
 
   return default_builtin_vectorization_cost (type_of_cost, vectype, misalign);
-- 
2.36.3


^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2024-01-10 15:45 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-01-10  9:58 [PATCH] RISC-V: Switch RVV cost model to generic vector cost model Juzhe-Zhong
2024-01-10 14:11 ` Robin Dapp
2024-01-10 14:18   ` 钟居哲
2024-01-10 14:40   ` 钟居哲
2024-01-10 15:04     ` Robin Dapp
2024-01-10 15:15       ` 钟居哲
2024-01-10 15:36         ` Robin Dapp
2024-01-10 15:45           ` 钟居哲

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