[Mesa-dev] [PATCH 113/133] nir: Add a basic constant folding pass
Connor Abbott
cwabbott0 at gmail.com
Mon Jan 5 22:24:39 PST 2015
On Tue, Dec 16, 2014 at 1:12 AM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> ---
> src/glsl/Makefile.sources | 1 +
> src/glsl/nir/nir.h | 1 +
> src/glsl/nir/nir_opt_constant_folding.c | 283 +++++++++++++++++++++++++++++++
> src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 2 +
> 4 files changed, 287 insertions(+)
> create mode 100644 src/glsl/nir/nir_opt_constant_folding.c
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index d243f12..7fd650b 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -36,6 +36,7 @@ NIR_FILES = \
> $(GLSL_SRCDIR)/nir/nir_metadata.c \
> $(GLSL_SRCDIR)/nir/nir_opcodes.c \
> $(GLSL_SRCDIR)/nir/nir_opcodes.h \
> + $(GLSL_SRCDIR)/nir/nir_opt_constant_folding.c \
> $(GLSL_SRCDIR)/nir/nir_opt_copy_propagate.c \
> $(GLSL_SRCDIR)/nir/nir_opt_cse.c \
> $(GLSL_SRCDIR)/nir/nir_opt_dce.c \
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index 630e841..46f069f 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -1403,6 +1403,7 @@ void nir_convert_to_ssa(nir_shader *shader);
> void nir_convert_from_ssa(nir_shader *shader);
>
> bool nir_opt_algebraic(nir_shader *shader);
> +bool nir_opt_constant_folding(nir_shader *shader);
>
> bool nir_opt_global_to_local(nir_shader *shader);
>
> diff --git a/src/glsl/nir/nir_opt_constant_folding.c b/src/glsl/nir/nir_opt_constant_folding.c
> new file mode 100644
> index 0000000..3523713
> --- /dev/null
> +++ b/src/glsl/nir/nir_opt_constant_folding.c
> @@ -0,0 +1,283 @@
> +/*
> + * 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 at jlekstrand.net)
> + *
> + */
> +
> +#include "nir.h"
> +#include <math.h>
> +
> +/*
> + * Implements SSA-based constant folding.
> + */
> +
> +struct constant_fold_state {
> + void *mem_ctx;
> + nir_function_impl *impl;
> + bool progress;
> +};
> +
> +#define SRC_COMP(T, IDX, CMP) src[IDX]->value.T[instr->src[IDX].swizzle[CMP]]
> +#define SRC(T, IDX) SRC_COMP(T, IDX, i)
> +#define DEST_COMP(T, CMP) dest->value.T[CMP]
> +#define DEST(T) DEST_COMP(T, i)
> +
> +#define FOLD_PER_COMP(EXPR) \
> + for (unsigned i = 0; i < instr->dest.dest.ssa.num_components; i++) { \
> + EXPR; \
> + } \
> +
> +static bool
> +constant_fold_alu_instr(nir_alu_instr *instr, void *void_state)
> +{
> + struct constant_fold_state *state = void_state;
> + nir_load_const_instr *src[4], *dest;
> +
> + if (!instr->dest.dest.is_ssa)
> + return false;
> +
> + for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
> + if (!instr->src[i].src.is_ssa)
> + return false;
> +
> + if (instr->src[i].src.ssa->parent_instr->type != nir_instr_type_load_const)
> + return false;
> +
> + src[i] = nir_instr_as_load_const(instr->src[i].src.ssa->parent_instr);
> + }
> +
> + dest = nir_load_const_instr_create(state->mem_ctx);
> + dest->array_elems = 0;
> + dest->num_components = instr->dest.dest.ssa.num_components;
> +
> + switch (instr->op) {
> + case nir_op_ineg:
> + FOLD_PER_COMP(DEST(i) = -SRC(i, 0));
> + break;
> + case nir_op_fneg:
> + FOLD_PER_COMP(DEST(f) = -SRC(f, 0));
> + break;
> + case nir_op_inot:
> + FOLD_PER_COMP(DEST(i) = ~SRC(i, 0));
> + break;
> + case nir_op_fnot:
> + FOLD_PER_COMP(DEST(f) = (SRC(f, 0) == 0.0f) ? 1.0f : 0.0f);
> + break;
> + case nir_op_frcp:
> + FOLD_PER_COMP(DEST(f) = 1.0f / SRC(f, 0));
> + break;
> + case nir_op_frsq:
> + FOLD_PER_COMP(DEST(f) = 1.0f / sqrt(SRC(f, 0)));
> + break;
> + case nir_op_fsqrt:
> + FOLD_PER_COMP(DEST(f) = sqrtf(SRC(f, 0)));
> + break;
> + case nir_op_fexp:
> + FOLD_PER_COMP(DEST(f) = expf(SRC(f, 0)));
> + break;
> + case nir_op_flog:
> + FOLD_PER_COMP(DEST(f) = logf(SRC(f, 0)));
> + break;
> + case nir_op_fexp2:
> + FOLD_PER_COMP(DEST(f) = exp2f(SRC(f, 0)));
> + break;
> + case nir_op_flog2:
> + FOLD_PER_COMP(DEST(f) = log2f(SRC(f, 0)));
> + break;
> + case nir_op_f2i:
> + FOLD_PER_COMP(DEST(i) = SRC(f, 0));
> + break;
> + case nir_op_f2u:
> + FOLD_PER_COMP(DEST(u) = SRC(f, 0));
> + break;
> + case nir_op_i2f:
> + FOLD_PER_COMP(DEST(f) = SRC(i, 0));
> + break;
> + case nir_op_f2b:
> + FOLD_PER_COMP(DEST(u) = (SRC(i, 0) == 0.0f) ? NIR_FALSE : NIR_TRUE);
> + break;
> + case nir_op_b2f:
> + FOLD_PER_COMP(DEST(f) = SRC(u, 0) ? 1.0f : 0.0f);
> + break;
> + case nir_op_i2b:
> + FOLD_PER_COMP(DEST(u) = SRC(i, 0) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_u2f:
> + FOLD_PER_COMP(DEST(f) = SRC(u, 0));
> + break;
> + case nir_op_bany2:
> + DEST_COMP(u, 0) = (SRC_COMP(u, 0, 0) || SRC_COMP(u, 0, 1)) ?
> + NIR_TRUE : NIR_FALSE;
> + break;
> + case nir_op_fadd:
> + FOLD_PER_COMP(DEST(f) = SRC(f, 0) + SRC(f, 1));
> + break;
> + case nir_op_iadd:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) + SRC(i, 1));
> + break;
> + case nir_op_fsub:
> + FOLD_PER_COMP(DEST(f) = SRC(f, 0) - SRC(f, 1));
> + break;
> + case nir_op_isub:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) - SRC(i, 1));
> + break;
> + case nir_op_fmul:
> + FOLD_PER_COMP(DEST(f) = SRC(f, 0) * SRC(f, 1));
> + break;
> + case nir_op_imul:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) * SRC(i, 1));
> + break;
> + case nir_op_fdiv:
> + FOLD_PER_COMP(DEST(f) = SRC(f, 0) / SRC(f, 1));
> + break;
> + case nir_op_idiv:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) / SRC(i, 1));
> + break;
> + case nir_op_udiv:
> + FOLD_PER_COMP(DEST(u) = SRC(u, 0) / SRC(u, 1));
> + break;
> + case nir_op_flt:
> + FOLD_PER_COMP(DEST(u) = (SRC(f, 0) < SRC(f, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_fge:
> + FOLD_PER_COMP(DEST(u) = (SRC(f, 0) >= SRC(f, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_feq:
> + FOLD_PER_COMP(DEST(u) = (SRC(f, 0) == SRC(f, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_fne:
> + FOLD_PER_COMP(DEST(u) = (SRC(f, 0) != SRC(f, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ilt:
> + FOLD_PER_COMP(DEST(u) = (SRC(i, 0) < SRC(i, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ige:
> + FOLD_PER_COMP(DEST(u) = (SRC(i, 0) >= SRC(i, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ieq:
> + FOLD_PER_COMP(DEST(u) = (SRC(i, 0) == SRC(i, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ine:
> + FOLD_PER_COMP(DEST(u) = (SRC(i, 0) != SRC(i, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ult:
> + FOLD_PER_COMP(DEST(u) = (SRC(u, 0) < SRC(u, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_uge:
> + FOLD_PER_COMP(DEST(u) = (SRC(u, 0) >= SRC(u, 1)) ? NIR_TRUE : NIR_FALSE);
> + break;
> + case nir_op_ishl:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) << SRC(i, 1));
> + break;
> + case nir_op_ishr:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) >> SRC(i, 1));
> + break;
> + case nir_op_ushr:
> + FOLD_PER_COMP(DEST(u) = SRC(u, 0) >> SRC(u, 1));
> + break;
> + case nir_op_iand:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) & SRC(i, 1));
> + break;
> + case nir_op_ior:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) | SRC(i, 1));
> + break;
> + case nir_op_ixor:
> + FOLD_PER_COMP(DEST(i) = SRC(i, 0) ^ SRC(i, 1));
> + break;
> + default:
> + ralloc_free(dest);
> + return false;
> + }
> +
> + if (instr->dest.saturate) {
> + assert(nir_op_infos[instr->op].output_type == nir_type_float);
> + for (int i = 0; i < 4; ++i) {
> + if (dest->value.f[i] > 1.0f)
> + dest->value.f[i] = 1.0f;
> + else if (dest->value.f[i] < 0.0f)
> + dest->value.f[i] = 0.0f;
> + }
> + }
I think this is just dead code... we don't even handle abs and negate.
> +
> + dest->dest.is_ssa = true;
> + nir_ssa_def_init(&dest->instr, &dest->dest.ssa,
> + instr->dest.dest.ssa.num_components,
> + instr->dest.dest.ssa.name);
> +
> + nir_instr_insert_before(&instr->instr, &dest->instr);
> +
> + nir_src new_src = {
> + .is_ssa = true,
> + .ssa = &dest->dest.ssa,
> + };
> +
> + nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, new_src, state->mem_ctx);
> +
> + nir_instr_remove(&instr->instr);
> + ralloc_free(instr);
> +
> + return true;
> +}
> +
> +static bool
> +constant_fold_block(nir_block *block, void *void_state)
> +{
> + struct constant_fold_state *state = void_state;
> +
> + nir_foreach_instr_safe(block, instr) {
> + if (instr->type != nir_instr_type_alu)
> + continue;
> +
> + state->progress |= constant_fold_alu_instr(nir_instr_as_alu(instr), state);
> + }
> +
> + return true;
> +}
> +
> +static bool
> +nir_opt_constant_folding_impl(nir_function_impl *impl)
> +{
> + struct constant_fold_state state;
> +
> + state.mem_ctx = ralloc_parent(impl);
> + state.impl = impl;
> + state.progress = false;
> +
> + nir_foreach_block(impl, constant_fold_block, &state);
> +
> + return state.progress;
> +}
> +
> +bool
> +nir_opt_constant_folding(nir_shader *shader)
> +{
> + bool progress = false;
> +
> + nir_foreach_overload(shader, overload) {
> + if (overload->impl)
> + progress |= nir_opt_constant_folding_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 039dd4d..f719c86 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> @@ -55,6 +55,8 @@ fs_visitor::emit_nir_code()
> nir_validate_shader(nir);
> progress |= nir_opt_algebraic(nir);
> nir_validate_shader(nir);
> + progress |= nir_opt_constant_folding(nir);
> + nir_validate_shader(nir);
> } while (progress);
>
> /* Lower a bunch of stuff */
> --
> 2.2.0
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
More information about the mesa-dev
mailing list