nir: Shrink store intrinsic num_components to the size used by the writemask.

This cuts a bunch of vector setup for undef components in the i965 vec4
backend.  Noticed while looking into codegen regressions in nir-to-tgsi.

brw results:
total instructions in shared programs: 3893221 -> 3881461 (-0.30%)
total cycles in shared programs: 113792154 -> 113810288 (0.02%)

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6054>
This commit is contained in:
Eric Anholt
2020-07-23 14:32:13 -07:00
committed by Marge Bot
parent 5f26c21e62
commit b440c28b78

View File

@@ -110,7 +110,7 @@ opt_shrink_vectors_alu(nir_builder *b, nir_alu_instr *instr)
}
static bool
opt_shrink_vectors_intrinsic(nir_intrinsic_instr *instr)
opt_shrink_vectors_intrinsic(nir_builder *b, nir_intrinsic_instr *instr)
{
switch (instr->intrinsic) {
case nir_intrinsic_load_uniform:
@@ -125,19 +125,44 @@ opt_shrink_vectors_intrinsic(nir_intrinsic_instr *instr)
case nir_intrinsic_load_global:
case nir_intrinsic_load_kernel_input:
case nir_intrinsic_load_scratch:
case nir_intrinsic_store_output:
case nir_intrinsic_store_per_vertex_output:
case nir_intrinsic_store_ssbo:
case nir_intrinsic_store_shared:
case nir_intrinsic_store_global:
case nir_intrinsic_store_scratch:
break;
default:
return false;
}
assert(nir_intrinsic_infos[instr->intrinsic].has_dest);
/* Must be a vectorized intrinsic that we can resize. */
assert(instr->num_components != 0);
if (nir_intrinsic_infos[instr->intrinsic].has_dest) {
/* loads: Trim the dest to the used channels */
if (shrink_dest_to_read_mask(&instr->dest.ssa)) {
instr->num_components = instr->dest.ssa.num_components;
return true;
}
} else {
/* Stores: trim the num_components stored according to the write
* mask.
*/
unsigned write_mask = nir_intrinsic_write_mask(instr);
unsigned last_bit = util_last_bit(write_mask);
if (last_bit < instr->num_components && instr->src[0].is_ssa) {
nir_ssa_def *def = nir_channels(b, instr->src[0].ssa,
BITSET_MASK(last_bit));
nir_instr_rewrite_src(&instr->instr,
&instr->src[0],
nir_src_for_ssa(def));
instr->num_components = last_bit;
return true;
}
}
return false;
}
@@ -164,7 +189,7 @@ opt_shrink_vectors_instr(nir_builder *b, nir_instr *instr)
return opt_shrink_vectors_alu(b, nir_instr_as_alu(instr));
case nir_instr_type_intrinsic:
return opt_shrink_vectors_intrinsic(nir_instr_as_intrinsic(instr));
return opt_shrink_vectors_intrinsic(b, nir_instr_as_intrinsic(instr));
case nir_instr_type_load_const:
return opt_shrink_vectors_load_const(nir_instr_as_load_const(instr));