Matt and I noticed that one of the shaders hurt by INTEL_USE_NIR=1 had
load_input and load_uniform intrinsics repeated several times, with the
same parameters, but each one generating a distinct SSA value. This
made ALU operations on those values appear distinct as well.
Generating distinct SSA values is silly - these are read only variables.
CSE'ing them makes everything use a single SSA value, which then allows
other operations to be CSE'd away as well.
Generalizing a bit, it seems like we should be able to safely CSE any
intrinsics that can be eliminated and reordered. I didn't implement
support for variables for the time being.
--- NIR instruction statistics ---
total instructions in shared programs: 2435936 -> 2023511 (-16.93%)
instructions in affected programs: 2413496 -> 2001071 (-17.09%)
helped: 16872
--- i965 instruction statistics ---
total instructions in shared programs: 6028987 -> 6008427 (-0.34%)
instructions in affected programs: 640654 -> 620094 (-3.21%)
helped: 2071
HURT: 585
GAINED: 14
LOST: 25
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
src/glsl/nir/nir_opt_cse.c | 38 ++++++++++++++++++++++++++++++++++++--
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/src/glsl/nir/nir_opt_cse.c b/src/glsl/nir/nir_opt_cse.c
index e7dba1d..6ad78f6 100644
--- a/src/glsl/nir/nir_opt_cse.c
+++ b/src/glsl/nir/nir_opt_cse.c
@@ -112,7 +112,32 @@ nir_instrs_equal(nir_instr *instr1, nir_instr *instr2)
return true;
}
- case nir_instr_type_intrinsic:
+ case nir_instr_type_intrinsic: {
+ nir_intrinsic_instr *intrinsic1 = nir_instr_as_intrinsic(instr1);
+ nir_intrinsic_instr *intrinsic2 = nir_instr_as_intrinsic(instr2);
+ const nir_intrinsic_info *info =
+ &nir_intrinsic_infos[intrinsic1->intrinsic];
+
+ if (intrinsic1->intrinsic != intrinsic2->intrinsic ||
+ intrinsic1->num_components != intrinsic2->num_components)
+ return false;
+
+ if (info->has_dest && intrinsic1->dest.ssa.num_components !=
+ intrinsic2->dest.ssa.num_components)
+ return false;
+
+ for (unsigned i = 0; i < info->num_srcs; i++) {
+ if (!nir_srcs_equal(intrinsic1->src[i], intrinsic2->src[i]))
+ return false;
+ }
+
+ for (unsigned i = 0; i < info->num_indices; i++) {
+ if (intrinsic1->const_index[i] != intrinsic2->const_index[i])
+ return false;
+ }
+
+ return true;
+ }
case nir_instr_type_call:
case nir_instr_type_jump:
case nir_instr_type_ssa_undef:
@@ -147,7 +172,13 @@ nir_instr_can_cse(nir_instr *instr)
nir_foreach_src(instr, src_is_ssa, NULL);
case nir_instr_type_tex:
return false; /* TODO */
- case nir_instr_type_intrinsic:
+ case nir_instr_type_intrinsic: {
+ const nir_intrinsic_info *info =
+ &nir_intrinsic_infos[nir_instr_as_intrinsic(instr)->intrinsic];
+ return (info->flags & NIR_INTRINSIC_CAN_ELIMINATE) &&
+ (info->flags & NIR_INTRINSIC_CAN_REORDER) &&
+ info->num_variables == 0; /* not implemented yet */
+ }
case nir_instr_type_call:
case nir_instr_type_jump:
case nir_instr_type_ssa_undef:
@@ -172,6 +203,9 @@ nir_instr_get_dest_ssa_def(nir_instr *instr)
case nir_instr_type_phi:
assert(nir_instr_as_phi(instr)->dest.is_ssa);
return &nir_instr_as_phi(instr)->dest.ssa;
+ case nir_instr_type_intrinsic:
+ assert(nir_instr_as_intrinsic(instr)->dest.is_ssa);
+ return &nir_instr_as_intrinsic(instr)->dest.ssa;
default:
unreachable("We never ask for any of these");
}
--
2.2.2
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