Commit 1cb11969 authored by Alyssa Rosenzweig's avatar Alyssa Rosenzweig Committed by Marge Bot
Browse files

pan/bi: Add simple constant folding pass



Cleans up swizzle lowering, and will be used for other cleanup as
well (fancy texturing tends to create a lot of foldable code).

Signed-off-by: Alyssa Rosenzweig's avatarAlyssa Rosenzweig <alyssa@collabora.com>
Part-of: <!10392>
parent 84756b98
/*
* Copyright (C) 2020 Collabora Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "compiler.h"
#include "bi_builder.h"
/* Dead simple constant folding to cleanup compiler frontend patterns. Before
* adding a new pattern here, check why you need it and whether we can avoid
* generating the constant BIR at all. */
static uint32_t
bi_fold_constant(bi_instr *I, bool *unsupported)
{
uint32_t a = I->src[0].value;
uint32_t b = I->src[1].value;
switch (I->op) {
case BI_OPCODE_SWZ_V2I16:
{
uint16_t lo = (a & 0xFFFF);
uint16_t hi = (a >> 16);
enum bi_swizzle swz = I->src[0].swizzle;
assert(swz < BI_SWIZZLE_H11);
/* Note order is H00, H01, H10, H11 */
return (((swz & (1 << 1)) ? hi : lo) << 0) |
(((swz & (1 << 0)) ? hi : lo) << 16);
}
case BI_OPCODE_MKVEC_V2I16:
{
bool hi_a = I->src[0].swizzle & BI_SWIZZLE_H11;
bool hi_b = I->src[1].swizzle & BI_SWIZZLE_H11;
uint16_t lo = (hi_a ? (a >> 16) : (a & 0xFFFF));
uint16_t hi = (hi_b ? (b >> 16) : (b & 0xFFFF));
return (hi << 16) | lo;
}
default:
*unsupported = true;
return 0;
}
}
static bool
bi_all_srcs_const(bi_instr *I)
{
bi_foreach_src(I, s) {
enum bi_index_type type = I->src[s].type;
if (!(type == BI_INDEX_NULL || type == BI_INDEX_CONSTANT))
return false;
}
return true;
}
void
bi_opt_constant_fold(bi_context *ctx)
{
bi_foreach_instr_global_safe(ctx, ins) {
if (!bi_all_srcs_const(ins)) continue;
bool unsupported = false;
uint32_t replace = bi_fold_constant(ins, &unsupported);
if (unsupported) continue;
/* Replace with constant move, to be copypropped */
bi_builder b = bi_init_builder(ctx, bi_after_instr(ins));
bi_mov_i32_to(&b, ins->dest[0], bi_imm_u32(replace));
bi_remove_instruction(ins);
}
}
......@@ -3078,8 +3078,12 @@ bifrost_compile_shader_nir(nir_shader *nir,
block->base.name = block_source_count++;
}
/* Runs before constant folding */
bi_lower_swizzle(ctx);
/* Runs before copy prop */
bi_opt_push_ubo(ctx);
bi_opt_constant_fold(ctx);
bi_opt_copy_prop(ctx);
bi_opt_dead_code_eliminate(ctx, false);
......@@ -3088,8 +3092,6 @@ bifrost_compile_shader_nir(nir_shader *nir,
bi_lower_branch(block);
}
bi_lower_swizzle(ctx);
if (bifrost_debug & BIFROST_DBG_SHADERS && !skip_internal)
bi_print_shader(ctx, stdout);
bi_schedule(ctx);
......
......@@ -753,6 +753,7 @@ void bi_print_shader(bi_context *ctx, FILE *fp);
void bi_opt_copy_prop(bi_context *ctx);
void bi_opt_dead_code_eliminate(bi_context *ctx, bool soft);
void bi_opt_push_ubo(bi_context *ctx);
void bi_opt_constant_fold(bi_context *ctx);
void bi_lower_swizzle(bi_context *ctx);
void bi_schedule(bi_context *ctx);
void bi_assign_scoreboard(bi_context *ctx);
......
......@@ -24,6 +24,7 @@ libpanfrost_bifrost_files = files(
'bi_liveness.c',
'bi_lower_swizzle.c',
'bi_print.c',
'bi_opt_constant_fold.c',
'bi_opt_copy_prop.c',
'bi_opt_dce.c',
'bi_opt_push_ubo.c',
......
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