Would it be possible to drop this patch since this all gets deleted later?
On Tue, Dec 16, 2014 at 1:05 AM, Jason Ekstrand <ja...@jlekstrand.net> wrote:
> ---
> src/glsl/Makefile.sources | 1 +
> src/glsl/nir/nir.h | 1 +
> src/glsl/nir/nir_opcodes.h | 1 +
> src/glsl/nir/nir_opt_peephole_ffma.c | 191
> +++++++++++++++++++++++++++++++
> src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 2 +
> 5 files changed, 196 insertions(+)
> create mode 100644 src/glsl/nir/nir_opt_peephole_ffma.c
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index 38ffb85..31608dc 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -32,6 +32,7 @@ NIR_FILES = \
> $(GLSL_SRCDIR)/nir/nir_opt_copy_propagate.c \
> $(GLSL_SRCDIR)/nir/nir_opt_dce.c \
> $(GLSL_SRCDIR)/nir/nir_opt_global_to_local.c \
> + $(GLSL_SRCDIR)/nir/nir_opt_peephole_ffma.c \
> $(GLSL_SRCDIR)/nir/nir_opt_peephole_select.c \
> $(GLSL_SRCDIR)/nir/nir_print.c \
> $(GLSL_SRCDIR)/nir/nir_remove_dead_variables.c \
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index bc2280b..e20eb7c 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -1374,6 +1374,7 @@ bool nir_opt_dce_impl(nir_function_impl *impl);
> bool nir_opt_dce(nir_shader *shader);
>
> bool nir_opt_peephole_select(nir_shader *shader);
> +bool nir_opt_peephole_ffma(nir_shader *shader);
>
> #ifdef __cplusplus
> } /* extern "C" */
> diff --git a/src/glsl/nir/nir_opcodes.h b/src/glsl/nir/nir_opcodes.h
> index 988f691..35d4634 100644
> --- a/src/glsl/nir/nir_opcodes.h
> +++ b/src/glsl/nir/nir_opcodes.h
> @@ -307,6 +307,7 @@ BINOP_HORIZ(vec2, 2, nir_type_unsigned, 1,
> nir_type_unsigned, 1, nir_type_unsign
> ARR(src1_size, src2_size, src3_size), \
> ARR(nir_type_unsigned, nir_type_unsigned, nir_type_unsigned))
>
> +/* fma(a, b, c) = (a * b) + c */
> TRIOP(ffma, nir_type_float)
>
> TRIOP(flrp, nir_type_float)
> diff --git a/src/glsl/nir/nir_opt_peephole_ffma.c
> b/src/glsl/nir/nir_opt_peephole_ffma.c
> new file mode 100644
> index 0000000..2c9b8e5
> --- /dev/null
> +++ b/src/glsl/nir/nir_opt_peephole_ffma.c
> @@ -0,0 +1,191 @@
> +/*
> + * 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 (ja...@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;
> + nir_function_impl *impl;
> + 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(state->impl, &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.impl = 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;
> +}
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> index b2c5863..b6720af 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> @@ -63,6 +63,8 @@ fs_visitor::emit_nir_code()
> nir_validate_shader(nir);
> nir_opt_peephole_select(nir);
> nir_validate_shader(nir);
> + nir_opt_peephole_ffma(nir);
> + nir_validate_shader(nir);
> nir_print_shader(nir, stderr);
>
> nir_convert_from_ssa(nir);
> --
> 2.2.0
>
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