Commit f77f4c00 authored by Jason Ekstrand's avatar Jason Ekstrand
Browse files

nir: Add a basic constant folding pass


Reviewed-by: default avatarConnor Abbott <cwabbott0@gmail.com>
parent d5410bd8
......@@ -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 \
......
......@@ -1399,6 +1399,7 @@ 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);
......
/*
* 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"
#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;
/* We shouldn't have any source modifiers in the optimization loop. */
assert(!instr->src[i].abs && !instr->src[i].negate);
src[i] = nir_instr_as_load_const(instr->src[i].src.ssa->parent_instr);
}
/* We shouldn't have any saturate modifiers in the optimization loop. */
assert(!instr->dest.saturate);
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;
}
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;
}
......@@ -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 */
......
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