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nir: Implement CSE on intrinsics that can be eliminated and reordered. 

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.

v2: Assert that info->num_variables == 0 (requested by Jason).

total NIR instructions in shared programs: 2435936 -> 2023511 (-16.93%)
NIR instructions in affected programs:     2413496 -> 2001071 (-17.09%)
helped:                                    16872

total i965 instructions in shared programs: 6028987 -> 6008427 (-0.34%)
i965 instructions in affected programs:     640654 -> 620094 (-3.21%)
helped:                                     2071
HURT:                                       585
GAINED:                                     14
LOST:                                       25

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
This commit is contained in:
Kenneth Graunke 2015-01-19 14:51:24 -08:00
parent cbdd623f13
commit 978b0a9cda
1 changed files with 38 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
src/glsl/nir/nir_opt_cse.c
View File

@ -112,7 +112,34 @@ 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;
}
assert(info->num_variables == 0);
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:
@ -151,7 +178,13 @@ nir_instr_can_cse(nir_instr *instr)
return true;
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:
@ -176,6 +209,9 @@ 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");
}