[Mesa-dev] [PATCH 018/133] nir: add an SSA-based copy propagation pass
Jason Ekstrand
jason at jlekstrand.net
Wed Dec 17 13:10:18 PST 2014
On Wed, Dec 17, 2014 at 12:07 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:
>
> On Tue, Dec 16, 2014 at 1:04 AM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > From: Connor Abbott <connor.abbott at intel.com>
> >
> > ---
> > src/glsl/Makefile.sources | 1 +
> > src/glsl/nir/nir.h | 3 +
> > src/glsl/nir/nir_opt_copy_propagate.c | 313
> ++++++++++++++++++++++++++++++++++
> > 3 files changed, 317 insertions(+)
> > create mode 100644 src/glsl/nir/nir_opt_copy_propagate.c
> >
> > diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> > index 0aaea58..556648b 100644
> > --- a/src/glsl/Makefile.sources
> > +++ b/src/glsl/Makefile.sources
> > @@ -25,6 +25,7 @@ NIR_FILES = \
> > $(GLSL_SRCDIR)/nir/nir_lower_variables_scalar.c \
> > $(GLSL_SRCDIR)/nir/nir_opcodes.c \
> > $(GLSL_SRCDIR)/nir/nir_opcodes.h \
> > + $(GLSL_SRCDIR)/nir/nir_opt_copy_propagate.c \
> > $(GLSL_SRCDIR)/nir/nir_opt_global_to_local.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 c2b4724..a5cb5ed 100644
> > --- a/src/glsl/nir/nir.h
> > +++ b/src/glsl/nir/nir.h
> > @@ -1293,6 +1293,9 @@ void nir_convert_to_ssa(nir_shader *shader);
> >
> > bool nir_opt_global_to_local(nir_shader *shader);
> >
> > +bool nir_copy_prop_impl(nir_function_impl *impl);
> > +bool nir_copy_prop(nir_shader *shader);
> > +
> > #ifdef __cplusplus
> > } /* extern "C" */
> > #endif
> > diff --git a/src/glsl/nir/nir_opt_copy_propagate.c
> b/src/glsl/nir/nir_opt_copy_propagate.c
> > new file mode 100644
> > index 0000000..a2be047
> > --- /dev/null
> > +++ b/src/glsl/nir/nir_opt_copy_propagate.c
> > @@ -0,0 +1,313 @@
> > +/*
> > + * 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:
> > + * Connor Abbott (cwabbott0 at gmail.com)
> > + *
> > + */
> > +
> > +#include "nir.h"
> > +#include <main/imports.h>
> > +
> > +/**
> > + * SSA-based copy propagation
> > + */
> > +
> > +static bool is_move(nir_alu_instr *instr)
> > +{
> > + if (instr->op != nir_op_fmov &&
> > + instr->op != nir_op_imov)
> > + return false;
> > +
> > + if (instr->dest.saturate)
> > + return false;
> > +
> > + /* we handle modifiers in a separate pass */
>
> This comment is stale now, since this pass should never see
> modifiers... maybe we should replace those if's with asserts to make
> that clear.
>
Easy enough to do.
>
> > +
> > + if (instr->src[0].abs || instr->src[0].negate)
> > + return false;
> > +
> > + if (!instr->src[0].src.is_ssa)
> > + return false;
> > +
> > + return true;
> > +
> > +}
> > +
> > +static bool
> > +is_swizzleless_move(nir_alu_instr *instr)
> > +{
> > + if (!is_move(instr))
> > + return false;
> > +
> > + for (unsigned i = 0; i < 4; i++) {
> > + if (!((instr->dest.write_mask >> i) & 1))
> > + break;
> > + if (instr->src[0].swizzle[i] != i)
> > + return false;
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool is_vec(nir_alu_instr *instr)
> > +{
> > + for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++)
> > + if (!instr->src[i].src.is_ssa)
> > + return false;
> > +
> > + return instr->op == nir_op_vec2 ||
> > + instr->op == nir_op_vec3 ||
> > + instr->op == nir_op_vec4;
> > +}
> > +
> > +typedef struct {
> > + nir_ssa_def *def;
> > + bool found;
> > +} search_def_state;
> > +
> > +static bool
> > +search_def(nir_src *src, void *_state)
> > +{
> > + search_def_state *state = (search_def_state *) _state;
> > +
> > + if (src->is_ssa && src->ssa == state->def)
> > + state->found = true;
> > +
> > + return true;
> > +}
> > +
> > +static void
> > +rewrite_src_instr(nir_src *src, nir_ssa_def *new_def, nir_instr
> *parent_instr)
> > +{
> > + nir_ssa_def *old_def = src->ssa;
> > +
> > + src->ssa = new_def;
> > +
> > + /*
> > + * The instruction could still use the old definition in one of its
> other
> > + * sources, so only remove the instruction from the uses if there
> are no
> > + * more uses left.
> > + */
> > +
> > + search_def_state search_state;
> > + search_state.def = old_def;
> > + search_state.found = false;
> > + nir_foreach_src(parent_instr, search_def, &search_state);
> > + if (!search_state.found) {
> > + struct set_entry *entry =
> > + _mesa_set_search(old_def->uses,
> _mesa_hash_pointer(parent_instr),
> > + parent_instr);
> > + assert(entry);
> > + _mesa_set_remove(old_def->uses, entry);
> > + }
> > +
> > + _mesa_set_add(new_def->uses, _mesa_hash_pointer(parent_instr),
> > + parent_instr);
> > +}
> > +
> > +static void
> > +rewrite_src_if(nir_if *if_stmt, nir_ssa_def *new_def)
> > +{
> > + nir_ssa_def *old_def = if_stmt->condition.ssa;
> > +
> > + if_stmt->condition.ssa = new_def;
> > +
> > + struct set_entry *entry =
> > + _mesa_set_search(old_def->if_uses, _mesa_hash_pointer(if_stmt),
> if_stmt);
> > + assert(entry);
> > + _mesa_set_remove(old_def->if_uses, entry);
> > +
> > + _mesa_set_add(new_def->if_uses, _mesa_hash_pointer(if_stmt),
> if_stmt);
> > +}
> > +
> > +static bool
> > +copy_prop_src(nir_src *src, nir_instr *parent_instr, nir_if *parent_if)
> > +{
> > + if (!src->is_ssa) {
> > + if (src->reg.indirect)
> > + return copy_prop_src(src, parent_instr, parent_if);
> > + return false;
> > + }
> > +
> > + nir_instr *src_instr = src->ssa->parent_instr;
> > + if (src_instr->type != nir_instr_type_alu)
> > + return false;
> > +
> > + nir_alu_instr *alu_instr = nir_instr_as_alu(src_instr);
> > + if (!is_swizzleless_move(alu_instr))
> > + return false;
> > +
> > + if (parent_instr)
> > + rewrite_src_instr(src, alu_instr->src[0].src.ssa, parent_instr);
> > + else
> > + rewrite_src_if(parent_if, alu_instr->src[0].src.ssa);
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +copy_prop_alu_src(nir_alu_instr *parent_alu_instr, unsigned index)
> > +{
> > + nir_alu_src *src = &parent_alu_instr->src[index];
> > + if (!src->src.is_ssa) {
> > + if (src->src.reg.indirect)
> > + return copy_prop_src(src->src.reg.indirect,
> &parent_alu_instr->instr,
> > + NULL);
> > + return false;
> > + }
> > +
> > + nir_instr *src_instr = src->src.ssa->parent_instr;
> > + if (src_instr->type != nir_instr_type_alu)
> > + return false;
> > +
> > + nir_alu_instr *alu_instr = nir_instr_as_alu(src_instr);
> > + if (!is_move(alu_instr) && !is_vec(alu_instr))
> > + return false;
> > +
> > + nir_ssa_def *def;
> > + unsigned new_swizzle[4] = {0, 0, 0, 0};
> > +
> > + if (alu_instr->op == nir_op_fmov ||
> > + alu_instr->op == nir_op_imov) {
> > + for (unsigned i = 0; i < 4; i++)
> > + new_swizzle[i] = alu_instr->src[0].swizzle[src->swizzle[i]];
> > + def = alu_instr->src[0].src.ssa;
> > + } else {
> > + def = NULL;
> > +
> > + for (unsigned i = 0; i < 4; i++) {
> > + if (!nir_alu_instr_channel_used(parent_alu_instr, index, i))
> > + continue;
> > +
> > + nir_ssa_def *new_def = alu_instr->src[src->swizzle[i]].src.ssa;
> > + if (def == NULL)
> > + def = new_def;
> > + else {
> > + if (def != new_def)
> > + return false;
> > + }
> > + new_swizzle[i] = alu_instr->src[src->swizzle[i]].swizzle[0];
> > + }
> > + }
> > +
> > + for (unsigned i = 0; i < 4; i++)
> > + src->swizzle[i] = new_swizzle[i];
> > +
> > + rewrite_src_instr(&src->src, def, &parent_alu_instr->instr);
> > +
> > + return true;
> > +}
> > +
> > +typedef struct {
> > + nir_instr *parent_instr;
> > + bool progress;
> > +} copy_prop_state;
> > +
> > +static bool
> > +copy_prop_src_cb(nir_src *src, void *_state)
> > +{
> > + copy_prop_state *state = (copy_prop_state *) _state;
> > + while (copy_prop_src(src, state->parent_instr, NULL))
> > + state->progress = true;
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +copy_prop_instr(nir_instr *instr)
> > +{
> > + if (instr->type == nir_instr_type_alu) {
> > + nir_alu_instr *alu_instr = nir_instr_as_alu(instr);
> > + bool progress = false;
> > +
> > + for (unsigned i = 0; i < nir_op_infos[alu_instr->op].num_inputs;
> i++)
> > + while (copy_prop_alu_src(alu_instr, i))
> > + progress = true;
> > +
> > + if (alu_instr->has_predicate)
> > + while (copy_prop_src(&alu_instr->predicate, instr, NULL))
> > + progress = true;
> > +
> > + if (!alu_instr->dest.dest.is_ssa &&
> alu_instr->dest.dest.reg.indirect)
> > + while (copy_prop_src(alu_instr->dest.dest.reg.indirect, instr,
> NULL))
> > + progress = true;
> > +
> > + return progress;
> > + }
> > +
> > + copy_prop_state state;
> > + state.parent_instr = instr;
> > + state.progress = false;
> > + nir_foreach_src(instr, copy_prop_src_cb, &state);
> > +
> > + return state.progress;
> > +}
> > +
> > +static bool
> > +copy_prop_if(nir_if *if_stmt)
> > +{
> > + return copy_prop_src(&if_stmt->condition, NULL, if_stmt);
> > +}
> > +
> > +static bool
> > +copy_prop_block(nir_block *block, void *_state)
> > +{
> > + bool *progress = (bool *) _state;
> > +
> > + nir_foreach_instr(block, instr) {
> > + if (copy_prop_instr(instr))
> > + *progress = true;
> > + }
> > +
> > + if (block->cf_node.node.next != NULL && /* check that we aren't the
> end node */
> > + !nir_cf_node_is_last(&block->cf_node) &&
> > + nir_cf_node_next(&block->cf_node)->type == nir_cf_node_if) {
> > + nir_if *if_stmt =
> nir_cf_node_as_if(nir_cf_node_next(&block->cf_node));
> > + if (copy_prop_if(if_stmt))
> > + *progress = true;
> > + }
> > +
> > + return true;
> > +}
> > +
> > +bool
> > +nir_copy_prop_impl(nir_function_impl *impl)
> > +{
> > + bool progress = false;
> > +
> > + nir_foreach_block(impl, copy_prop_block, &progress);
> > + return progress;
> > +}
> > +
> > +bool
> > +nir_copy_prop(nir_shader *shader)
> > +{
> > + bool progress = false;
> > +
> > + nir_foreach_overload(shader, overload) {
> > + if (overload->impl && nir_copy_prop_impl(overload->impl))
> > + progress = true;
> > + }
> > +
> > + return progress;
> > +}
> > --
> > 2.2.0
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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