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r300: Request that nir-to-tgsi avoid generating TGSI_OPCODE_CMP. 

Given that our fcsels are on float-bools, we can emit the LRP directly and
save the backend having to emit a SLT to turn the CMP src[0] into a bool.

This required passing a codegen flags struct for nir-to-tgsi.  I think
this is a good way forward for it, as the alternative I think has mostly
been adding flags to nir_shader_compiler_options (since adding
PIPE_SHADER_CAPs is an unreasonable amount of pain).

r300 shader-db:
total instructions in shared programs: 1484320 -> 1472463 (-0.80%)
instructions in affected programs: 243588 -> 231731 (-4.87%)
total temps in shared programs: 212485 -> 212143 (-0.16%)
temps in affected programs: 3845 -> 3503 (-8.89%)

Acked-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14886>
This commit is contained in:
Emma Anholt 2022-02-04 14:27:54 -08:00 committed by Marge Bot
parent 4a1ba7914a
commit d52d500f17
4 changed files with 47 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/gallium/auxiliary/nir/nir_to_tgsi.c
View File

@ -37,6 +37,7 @@
struct ntt_compile {
nir_shader *s;
nir_function_impl *impl;
const struct nir_to_tgsi_options *options;
struct pipe_screen *screen;
struct ureg_program *ureg;
@ -1156,15 +1157,26 @@ ntt_emit_alu(struct ntt_compile *c, nir_alu_instr *instr)
break;
case nir_op_fcsel:
/* NIR is src0 != 0 ? src1 : src2.
* TGSI is src0 < 0 ? src1 : src2.
/* NIR fcsel is src0 != 0 ? src1 : src2.
* TGSI CMP is src0 < 0 ? src1 : src2.
*
* However, fcsel so far as I can find only appears on bools-as-floats
* (1.0 or 0.0), so we can just negate it for the TGSI op. It's
* important to not have an abs here, as i915g has to make extra
* instructions to do the abs.
*/
ureg_CMP(c->ureg, dst, ureg_negate(src[0]), src[1], src[2]);
if (c->options->lower_cmp) {
/* If the HW doesn't support TGSI CMP (r300 VS), then lower it to a
* LRP on the boolean 1.0/0.0 value, instead of requiring the
* backend to turn the src0 into 1.0/0.0 first.
*
* We don't use this in general because some hardware (i915 FS) the
* LRP gets expanded to MUL/MAD.
*/
ureg_LRP(c->ureg, dst, src[0], src[1], src[2]);
} else {
ureg_CMP(c->ureg, dst, ureg_negate(src[0]), src[1], src[2]);
}
break;
/* It would be nice if we could get this left as scalar in NIR, since
@ -2906,7 +2918,8 @@ nir_to_tgsi_lower_tex(nir_shader *s)
}
static void
ntt_fix_nir_options(struct pipe_screen *screen, struct nir_shader *s)
ntt_fix_nir_options(struct pipe_screen *screen, struct nir_shader *s,
const struct nir_to_tgsi_options *ntt_options)
{
const struct nir_shader_compiler_options *options = s->options;
bool lower_fsqrt =
@ -3051,6 +3064,14 @@ nir_lower_primid_sysval_to_input(nir_shader *s)
nir_lower_primid_sysval_to_input_lower, &input);
}
const void *
nir_to_tgsi(struct nir_shader *s,
struct pipe_screen *screen)
{
static const struct nir_to_tgsi_options default_ntt_options = {0};
return nir_to_tgsi_options(s, screen, &default_ntt_options);
}
/**
* Translates the NIR shader to TGSI.
*
@ -3058,9 +3079,9 @@ nir_lower_primid_sysval_to_input(nir_shader *s)
* We take ownership of the NIR shader passed, returning a reference to the new
* TGSI tokens instead. If you need to keep the NIR, then pass us a clone.
*/
const void *
nir_to_tgsi(struct nir_shader *s,
struct pipe_screen *screen)
const void *nir_to_tgsi_options(struct nir_shader *s,
struct pipe_screen *screen,
const struct nir_to_tgsi_options *options)
{
struct ntt_compile *c;
const void *tgsi_tokens;
@ -3070,7 +3091,7 @@ nir_to_tgsi(struct nir_shader *s,
PIPE_SHADER_CAP_INTEGERS);
const struct nir_shader_compiler_options *original_options = s->options;
ntt_fix_nir_options(screen, s);
ntt_fix_nir_options(screen, s, options);
NIR_PASS_V(s, nir_lower_io, nir_var_shader_in | nir_var_shader_out,
type_size, (nir_lower_io_options)0);
@ -3157,6 +3178,7 @@ nir_to_tgsi(struct nir_shader *s,
c = rzalloc(NULL, struct ntt_compile);
c->screen = screen;
c->options = options;
c->needs_texcoord_semantic =
screen->get_param(screen, PIPE_CAP_TGSI_TEXCOORD);

10
src/gallium/auxiliary/nir/nir_to_tgsi.h
View File

@ -24,12 +24,22 @@
#ifndef NIR_TO_TGSI_H
#define NIR_TO_TGSI_H
#include <stdbool.h>
struct nir_shader;
struct pipe_screen;
struct nir_to_tgsi_options {
bool lower_cmp;
};
const void *nir_to_tgsi(struct nir_shader *s,
struct pipe_screen *screen);
const void *nir_to_tgsi_options(struct nir_shader *s,
struct pipe_screen *screen,
const struct nir_to_tgsi_options *ntt_options);
const void *
nir_to_tgsi_get_compiler_options(struct pipe_screen *pscreen,
enum pipe_shader_ir ir,

6
src/gallium/drivers/r300/ci/r300-rv515-fails.txt
View File

@ -48,12 +48,6 @@ dEQP-GLES2.functional.rasterization.primitives.line_loop_wide,Fail
dEQP-GLES2.functional.shaders.functions.control_flow.mixed_return_break_continue_vertex,Fail
dEQP-GLES2.functional.shaders.functions.control_flow.mixed_return_break_continue_fragment,Fail
# "No free temporary to use for predicate stack counter."
dEQP-GLES2.functional.shaders.indexing.tmp_array.float_const_write_dynamic_loop_read_vertex,Fail
dEQP-GLES2.functional.shaders.indexing.tmp_array.vec2_const_write_dynamic_loop_read_vertex,Fail
dEQP-GLES2.functional.shaders.indexing.tmp_array.vec3_const_write_dynamic_loop_read_vertex,Fail
dEQP-GLES2.functional.shaders.indexing.tmp_array.vec4_const_write_dynamic_loop_read_vertex,Fail
# "Rewrite of inst 0 failed Can't allocate source for Inst 4 src_type=1 new_index=1 new_mask=1"
dEQP-GLES2.functional.shaders.indexing.vector_subscript.vec2_dynamic_subscript_write_component_read_fragment,Fail
dEQP-GLES2.functional.shaders.indexing.vector_subscript.vec2_dynamic_subscript_write_direct_read_fragment,Fail

8
src/gallium/drivers/r300/r300_state.c
View File

@ -1943,7 +1943,13 @@ static void* r300_create_vs_state(struct pipe_context* pipe,
vs->state = *shader;
if (vs->state.type == PIPE_SHADER_IR_NIR) {
vs->state.tokens = nir_to_tgsi(shader->ir.nir, pipe->screen);
static const struct nir_to_tgsi_options swtcl_options = {0};
static const struct nir_to_tgsi_options hwtcl_options = {
.lower_cmp = true,
};
vs->state.tokens = nir_to_tgsi_options(shader->ir.nir, pipe->screen,
r300->screen->caps.has_tcl ?
&hwtcl_options : &swtcl_options);
} else {
assert(vs->state.type == PIPE_SHADER_IR_TGSI);
/* we need to keep a local copy of the tokens */