Re: [PATCH] LoongArch: Increase cost of vector aligned store/load.

[WANG Xuerui]

On 11/16/23 14:17, Jiahao Xu wrote:

Based on SPEC2017 performance evaluation results, making them equal to the
cost of unaligned store/load to avoid odd alignment peeling is better.

Paraphrasing a bit to shorten the subject of the sentence:

"it's better to make them equal to ... so as to avoid odd-alignment peeling"

gcc/ChangeLog:

        * config/loongarch/loongarch.cc
        (loongarch_builtin_vectorization_cost): Adjust.

diff --git a/gcc/config/loongarch/loongarch.cc 
b/gcc/config/loongarch/loongarch.cc
index 738911661d7..d05743bec87 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -3893,11 +3893,9 @@ loongarch_builtin_vectorization_cost (enum 
vect_cost_for_stmt type_of_cost,
        case scalar_stmt:
        case scalar_load:
        case vector_stmt:
-      case vector_load:
        case vec_to_scalar:
        case scalar_to_vec:
        case scalar_store:
-      case vector_store:
        return 1;

case vec_promote_demote:

@@ -3905,6 +3903,8 @@ loongarch_builtin_vectorization_cost (enum 
vect_cost_for_stmt type_of_cost,
        return LASX_SUPPORTED_MODE_P (mode)
          && !LSX_SUPPORTED_MODE_P (mode) ? 2 : 1;

+ case vector_load:

+      case vector_store:
        case unaligned_load:
        case unaligned_store:
        return 2;