+++ /dev/null
-/*
- * Copyright © 2014 Intel Corporation
- *
- * 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:
- * Jason Ekstrand (jason@jlekstrand.net)
- *
- */
-
-#include "nir.h"
-
-/*
- * Implements a small peephole optimization that looks for a multiply that
- * is only ever used in an add and replaces both with an fma.
- */
-
-struct peephole_ffma_state {
- void *mem_ctx;
- bool progress;
-};
-
-static inline nir_alu_instr *
-get_mul_for_src(nir_alu_instr *add, unsigned idx)
-{
- if (!add->src[idx].src.is_ssa)
- return NULL;
-
- /* We can't handle these in between the operations */
- if (add->src[idx].negate || add->src[idx].abs)
- return NULL;
-
- nir_instr *instr = add->src[idx].src.ssa->parent_instr;
- if (instr->type != nir_instr_type_alu)
- return NULL;
-
- nir_alu_instr *mul = nir_instr_as_alu(instr);
- if (mul->op != nir_op_fmul)
- return NULL;
-
- /* Can't handle a saturate in between */
- if (mul->dest.saturate)
- return NULL;
-
- /* We already know that the same source is not used twice in the add and
- * we will assume valid use-def information, so this check is sufficient
- */
- if (mul->dest.dest.ssa.uses->entries > 1)
- return NULL; /* Not the only use */
-
- return mul;
-}
-
-/* Copies (and maybe swizzles) the given ALU source */
-static inline void
-copy_alu_src(void *mem_ctx, nir_alu_src *new_src, nir_alu_src old_src,
- uint8_t *swizzle)
-{
- new_src->src = nir_src_copy(old_src.src, mem_ctx);
- new_src->abs = old_src.abs;
- new_src->negate = old_src.negate;
-
- if (swizzle == NULL) {
- memcpy(new_src->swizzle, old_src.swizzle, sizeof old_src.swizzle);
- } else {
- for (int i = 0; i < 4; ++i) {
- if (swizzle[i] < 4)
- new_src->swizzle[i] = old_src.swizzle[swizzle[i]];
- }
- }
-}
-
-static bool
-nir_opt_peephole_ffma_block(nir_block *block, void *void_state)
-{
- struct peephole_ffma_state *state = void_state;
-
- nir_foreach_instr_safe(block, instr) {
- if (instr->type != nir_instr_type_alu)
- continue;
-
- nir_alu_instr *add = nir_instr_as_alu(instr);
- if (add->op != nir_op_fadd)
- continue;
-
- /* TODO: Maybe bail if this expression is considered "precise"? */
-
- /* This, is the case a + a. We would rather handle this with an
- * algebraic reduction than fuse it. Also, we want to only fuse
- * things where the multiply is used only once and, in this case,
- * it would be used twice by the same instruction.
- */
- if (add->src[0].src.is_ssa && add->src[1].src.is_ssa &&
- add->src[0].src.ssa == add->src[1].src.ssa)
- continue;
-
- nir_alu_instr *mul = get_mul_for_src(add, 0);
- unsigned mul_src = 0;
-
- if (mul == NULL) {
- mul = get_mul_for_src(add, 1);
- mul_src = 1;
- }
-
- if (mul == NULL)
- continue;
-
- nir_alu_instr *ffma = nir_alu_instr_create(state->mem_ctx, nir_op_ffma);
- ffma->dest.saturate = add->dest.saturate;
- ffma->dest.write_mask = add->dest.write_mask;
-
- copy_alu_src(state->mem_ctx, &ffma->src[0], mul->src[0],
- add->src[mul_src].swizzle);
- copy_alu_src(state->mem_ctx, &ffma->src[1], mul->src[1],
- add->src[mul_src].swizzle);
- copy_alu_src(state->mem_ctx, &ffma->src[2], add->src[1 - mul_src], NULL);
-
- if (add->dest.dest.is_ssa) {
- ffma->dest.dest.is_ssa = true;
- nir_ssa_def_init(&ffma->instr, &ffma->dest.dest.ssa,
- add->dest.dest.ssa.num_components,
- add->dest.dest.ssa.name);
-
- nir_src ffma_dest_src = {
- .is_ssa = true,
- .ssa = &ffma->dest.dest.ssa,
- };
- nir_ssa_def_rewrite_uses(&add->dest.dest.ssa, ffma_dest_src,
- state->mem_ctx);
- } else {
- ffma->dest.dest = nir_dest_copy(add->dest.dest, state->mem_ctx);
- }
-
- nir_instr_insert_before(&add->instr, &ffma->instr);
- nir_instr_remove(&add->instr);
- nir_instr_remove(&mul->instr);
-
- state->progress = true;
- }
-
- return true;
-}
-
-static bool
-nir_opt_peephole_ffma_impl(nir_function_impl *impl)
-{
- struct peephole_ffma_state state;
-
- state.mem_ctx = ralloc_parent(impl);
- state.progress = false;
-
- nir_foreach_block(impl, nir_opt_peephole_ffma_block, &state);
-
- if (state.progress)
- nir_metadata_dirty(impl, nir_metadata_block_index |
- nir_metadata_dominance);
-
- return state.progress;
-}
-
-bool
-nir_opt_peephole_ffma(nir_shader *shader)
-{
- bool progress = false;
-
- nir_foreach_overload(shader, overload) {
- if (overload->impl)
- progress |= nir_opt_peephole_ffma_impl(overload->impl);
- }
-
- return progress;
-}
projects / mesa.git / commitdiff