aarch64: Add gather_load_xNN_cost tuning fields
This patch adds tuning fields for the total cost of a gather load
instruction. Until now, we've costed them as one scalar load
per element instead. Those scalar_load-based values are also
what the patch uses to fill in the new fields for existing
cost structures.
gcc/
* config/aarch64/aarch64-protos.h (sve_vec_cost):
Add gather_load_x32_cost and gather_load_x64_cost.
* config/aarch64/aarch64.c (generic_sve_vector_cost)
(a64fx_sve_vector_cost, neoversev1_sve_vector_cost): Update
accordingly, using the values given by the scalar_load * number
of elements calculation that we used previously.
(aarch64_detect_vector_stmt_subtype): Use the new fields.
diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
index fb4ce8e..b91eeeb 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -259,12 +259,16 @@
unsigned int fadda_f16_cost,
unsigned int fadda_f32_cost,
unsigned int fadda_f64_cost,
+ unsigned int gather_load_x32_cost,
+ unsigned int gather_load_x64_cost,
unsigned int scatter_store_elt_cost)
: simd_vec_cost (base),
clast_cost (clast_cost),
fadda_f16_cost (fadda_f16_cost),
fadda_f32_cost (fadda_f32_cost),
fadda_f64_cost (fadda_f64_cost),
+ gather_load_x32_cost (gather_load_x32_cost),
+ gather_load_x64_cost (gather_load_x64_cost),
scatter_store_elt_cost (scatter_store_elt_cost)
{}
@@ -279,6 +283,11 @@
const int fadda_f32_cost;
const int fadda_f64_cost;
+ /* The cost of a gather load instruction. The x32 value is for loads
+ of 32-bit elements and the x64 value is for loads of 64-bit elements. */
+ const int gather_load_x32_cost;
+ const int gather_load_x64_cost;
+
/* The per-element cost of a scatter store. */
const int scatter_store_elt_cost;
};
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index b14b6f2..36f1180 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -675,6 +675,8 @@
2, /* fadda_f16_cost */
2, /* fadda_f32_cost */
2, /* fadda_f64_cost */
+ 4, /* gather_load_x32_cost */
+ 2, /* gather_load_x64_cost */
1 /* scatter_store_elt_cost */
};
@@ -744,6 +746,8 @@
13, /* fadda_f16_cost */
13, /* fadda_f32_cost */
13, /* fadda_f64_cost */
+ 64, /* gather_load_x32_cost */
+ 32, /* gather_load_x64_cost */
1 /* scatter_store_elt_cost */
};
@@ -1739,6 +1743,8 @@
19, /* fadda_f16_cost */
11, /* fadda_f32_cost */
8, /* fadda_f64_cost */
+ 32, /* gather_load_x32_cost */
+ 16, /* gather_load_x64_cost */
3 /* scatter_store_elt_cost */
};
@@ -14958,6 +14964,19 @@
&& DR_IS_WRITE (STMT_VINFO_DATA_REF (stmt_info)))
return simd_costs->store_elt_extra_cost;
+ /* Detect SVE gather loads, which are costed as a single scalar_load
+ for each element. We therefore need to divide the full-instruction
+ cost by the number of elements in the vector. */
+ if (kind == scalar_load
+ && sve_costs
+ && STMT_VINFO_MEMORY_ACCESS_TYPE (stmt_info) == VMAT_GATHER_SCATTER)
+ {
+ unsigned int nunits = vect_nunits_for_cost (vectype);
+ if (GET_MODE_UNIT_BITSIZE (TYPE_MODE (vectype)) == 64)
+ return { sve_costs->gather_load_x64_cost, nunits };
+ return { sve_costs->gather_load_x32_cost, nunits };
+ }
+
/* Detect cases in which a scalar_store is really storing one element
in a scatter operation. */
if (kind == scalar_store
