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/*
* 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.
*
* Authors (Collabora):
* Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
*/
#include "compiler.h"
/* Finds the clause type required or return none */
static bool
bi_is_fragz(bi_instruction *ins)
{
if (!(ins->src[0] & BIR_INDEX_CONSTANT))
return false;
return (ins->constant.u32 == BIFROST_FRAGZ);
}
static enum bifrost_clause_type
bi_clause_type_for_ins(bi_instruction *ins)
{
unsigned T = ins->type;
/* Only high latency ops impose clause types */
if (!(bi_class_props[T] & BI_SCHED_HI_LATENCY))
return BIFROST_CLAUSE_NONE;
switch (T) {
case BI_BRANCH:
case BI_DISCARD:
return BIFROST_CLAUSE_NONE;
case BI_LOAD_VAR:
if (bi_is_fragz(ins))
return BIFROST_CLAUSE_FRAGZ;
return BIFROST_CLAUSE_LOAD_VARY;
case BI_LOAD_UNIFORM:
case BI_LOAD_ATTR:
case BI_LOAD_VAR_ADDRESS:
return BIFROST_CLAUSE_UBO;
case BI_TEX:
return BIFROST_CLAUSE_TEX;
case BI_LOAD:
return BIFROST_CLAUSE_SSBO_LOAD;
case BI_STORE:
case BI_STORE_VAR:
return BIFROST_CLAUSE_SSBO_STORE;
case BI_BLEND:
return BIFROST_CLAUSE_BLEND;
case BI_ATEST:
return BIFROST_CLAUSE_ATEST;
default:
unreachable("Invalid high-latency class");
}
}
/* There is an encoding restriction against FMA fp16 add/min/max
* having both sources with abs(..) with a duplicated source. This is
* due to the packing being order-sensitive, so the ports must end up distinct
* to handle both having abs(..). The swizzle doesn't matter here. Note
* BIR_INDEX_REGISTER generally should not be used pre-schedule (TODO: enforce
* this).
*/
static bool
bi_ambiguous_abs(bi_instruction *ins)
{
bool classy = bi_class_props[ins->type] & BI_NO_ABS_ABS_FP16_FMA;
bool typey = ins->dest_type == nir_type_float16;
bool absy = ins->src_abs[0] && ins->src_abs[1];
return classy && typey && absy;
}
/* New Bifrost (which?) don't seem to have ICMP on FMA */
static bool
bi_icmp(bi_instruction *ins)
{
bool ic = nir_alu_type_get_base_type(ins->src_types[0]) != nir_type_float;
return ic && (ins->type == BI_CMP);
}
/* Lowers FMOV to ADD #0, since FMOV doesn't exist on the h/w and this is the
* latest time it's sane to lower (it's useful to distinguish before, but we'll
* need this handle during scheduling to ensure the ports get modeled
* correctly with respect to the new zero source) */
static void
bi_lower_fmov(bi_instruction *ins)
{
if (ins->type != BI_FMOV)
return;
ins->type = BI_ADD;
ins->src[1] = BIR_INDEX_ZERO;
ins->src_types[1] = ins->src_types[0];
}
/* Eventually, we'll need a proper scheduling, grouping instructions
* into clauses and ordering/assigning grouped instructions to the
* appropriate FMA/ADD slots. Right now we do the dumbest possible
* thing just to have the scheduler stubbed out so we can focus on
* codegen */
void
bi_schedule(bi_context *ctx)
{
unsigned ids = 0;
unsigned last_id = 0;
bool is_first = true;
bi_foreach_block(ctx, block) {
bi_block *bblock = (bi_block *) block;
list_inithead(&bblock->clauses);
bi_foreach_instr_in_block(bblock, ins) {
/* Convenient time to lower */
bi_lower_fmov(ins);
unsigned props = bi_class_props[ins->type];
bi_clause *u = rzalloc(ctx, bi_clause);
u->bundle_count = 1;
/* Check for scheduling restrictions */
bool can_fma = props & BI_SCHED_FMA;
bool can_add = props & BI_SCHED_ADD;
can_fma &= !bi_ambiguous_abs(ins);
can_fma &= !bi_icmp(ins);
assert(can_fma || can_add);
if (can_fma)
u->bundles[0].fma = ins;
else
u->bundles[0].add = ins;
u->scoreboard_id = ids++;
if (is_first)
is_first = false;
else {
/* Rule: first instructions cannot have write barriers */
u->dependencies |= (1 << last_id);
u->data_register_write_barrier = true;
}
if (ins->type == BI_ATEST)
u->dependencies |= (1 << 6);
if (ins->type == BI_BLEND)
u->dependencies |= (1 << 6) | (1 << 7);
ids = ids & 1;
last_id = u->scoreboard_id;
u->back_to_back = false;
u->constant_count = 1;
u->constants[0] = ins->constant.u64;
u->clause_type = bi_clause_type_for_ins(ins);
list_addtail(&u->link, &bblock->clauses);
}
bblock->scheduled = true;
}
}
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