*
* Authors:
* Jason Ekstrand (jason@jlekstrand.net)
+ * Connor Abbott (cwabbott0@gmail.com)
*
*/
-#include "nir.h"
+#include "nir_instr_set.h"
/*
* Implements common subexpression elimination
*/
-struct cse_state {
- void *mem_ctx;
- bool progress;
-};
-
-static bool
-nir_alu_srcs_equal(nir_alu_instr *alu1, nir_alu_instr *alu2, unsigned src)
-{
- if (alu1->src[src].abs != alu2->src[src].abs ||
- alu1->src[src].negate != alu2->src[src].negate)
- return false;
-
- for (unsigned i = 0; i < nir_ssa_alu_instr_src_components(alu1, src); i++) {
- if (alu1->src[src].swizzle[i] != alu2->src[src].swizzle[i])
- return false;
- }
-
- return nir_srcs_equal(alu1->src[src].src, alu2->src[src].src);
-}
-
-static bool
-nir_instrs_equal(nir_instr *instr1, nir_instr *instr2)
-{
- if (instr1->type != instr2->type)
- return false;
-
- switch (instr1->type) {
- case nir_instr_type_alu: {
- nir_alu_instr *alu1 = nir_instr_as_alu(instr1);
- nir_alu_instr *alu2 = nir_instr_as_alu(instr2);
-
- if (alu1->op != alu2->op)
- return false;
-
- /* TODO: We can probably acutally do something more inteligent such
- * as allowing different numbers and taking a maximum or something
- * here */
- if (alu1->dest.dest.ssa.num_components != alu2->dest.dest.ssa.num_components)
- return false;
-
- for (unsigned i = 0; i < nir_op_infos[alu1->op].num_inputs; i++) {
- if (!nir_alu_srcs_equal(alu1, alu2, i))
- return false;
- }
- return true;
- }
- case nir_instr_type_tex:
- return false;
- case nir_instr_type_load_const: {
- nir_load_const_instr *load1 = nir_instr_as_load_const(instr1);
- nir_load_const_instr *load2 = nir_instr_as_load_const(instr2);
-
- if (load1->def.num_components != load2->def.num_components)
- return false;
-
- return memcmp(load1->value.f, load2->value.f,
- load1->def.num_components * sizeof(*load2->value.f)) == 0;
- }
- case nir_instr_type_phi: {
- nir_phi_instr *phi1 = nir_instr_as_phi(instr1);
- nir_phi_instr *phi2 = nir_instr_as_phi(instr2);
-
- if (phi1->instr.block != phi2->instr.block)
- return false;
-
- nir_foreach_phi_src(phi1, src1) {
- nir_foreach_phi_src(phi2, src2) {
- if (src1->pred == src2->pred) {
- if (!nir_srcs_equal(src1->src, src2->src))
- return false;
-
- break;
- }
- }
- }
-
- return true;
- }
- case nir_instr_type_intrinsic: {
- nir_intrinsic_instr *intrinsic1 = nir_instr_as_intrinsic(instr1);
- nir_intrinsic_instr *intrinsic2 = nir_instr_as_intrinsic(instr2);
- const nir_intrinsic_info *info =
- &nir_intrinsic_infos[intrinsic1->intrinsic];
-
- if (intrinsic1->intrinsic != intrinsic2->intrinsic ||
- intrinsic1->num_components != intrinsic2->num_components)
- return false;
-
- if (info->has_dest && intrinsic1->dest.ssa.num_components !=
- intrinsic2->dest.ssa.num_components)
- return false;
-
- for (unsigned i = 0; i < info->num_srcs; i++) {
- if (!nir_srcs_equal(intrinsic1->src[i], intrinsic2->src[i]))
- return false;
- }
-
- assert(info->num_variables == 0);
-
- for (unsigned i = 0; i < info->num_indices; i++) {
- if (intrinsic1->const_index[i] != intrinsic2->const_index[i])
- return false;
- }
-
- return true;
- }
- case nir_instr_type_call:
- case nir_instr_type_jump:
- case nir_instr_type_ssa_undef:
- case nir_instr_type_parallel_copy:
- default:
- unreachable("Invalid instruction type");
- }
-
- return false;
-}
-
-static bool
-src_is_ssa(nir_src *src, void *data)
-{
- (void) data;
- return src->is_ssa;
-}
-
-static bool
-dest_is_ssa(nir_dest *dest, void *data)
-{
- (void) data;
- return dest->is_ssa;
-}
+/*
+ * Visits and CSE's the given block and all its descendants in the dominance
+ * tree recursively. Note that the instr_set is guaranteed to only ever
+ * contain instructions that dominate the current block.
+ */
static bool
-nir_instr_can_cse(nir_instr *instr)
-{
- /* We only handle SSA. */
- if (!nir_foreach_dest(instr, dest_is_ssa, NULL) ||
- !nir_foreach_src(instr, src_is_ssa, NULL))
- return false;
-
- switch (instr->type) {
- case nir_instr_type_alu:
- case nir_instr_type_load_const:
- case nir_instr_type_phi:
- return true;
- case nir_instr_type_tex:
- return false; /* TODO */
- case nir_instr_type_intrinsic: {
- const nir_intrinsic_info *info =
- &nir_intrinsic_infos[nir_instr_as_intrinsic(instr)->intrinsic];
- return (info->flags & NIR_INTRINSIC_CAN_ELIMINATE) &&
- (info->flags & NIR_INTRINSIC_CAN_REORDER) &&
- info->num_variables == 0; /* not implemented yet */
- }
- case nir_instr_type_call:
- case nir_instr_type_jump:
- case nir_instr_type_ssa_undef:
- return false;
- case nir_instr_type_parallel_copy:
- default:
- unreachable("Invalid instruction type");
- }
-
- return false;
-}
-
-static nir_ssa_def *
-nir_instr_get_dest_ssa_def(nir_instr *instr)
+cse_block(nir_block *block, struct set *instr_set)
{
- switch (instr->type) {
- case nir_instr_type_alu:
- assert(nir_instr_as_alu(instr)->dest.dest.is_ssa);
- return &nir_instr_as_alu(instr)->dest.dest.ssa;
- case nir_instr_type_load_const:
- return &nir_instr_as_load_const(instr)->def;
- case nir_instr_type_phi:
- assert(nir_instr_as_phi(instr)->dest.is_ssa);
- return &nir_instr_as_phi(instr)->dest.ssa;
- case nir_instr_type_intrinsic:
- assert(nir_instr_as_intrinsic(instr)->dest.is_ssa);
- return &nir_instr_as_intrinsic(instr)->dest.ssa;
- default:
- unreachable("We never ask for any of these");
- }
-}
-
-static void
-nir_opt_cse_instr(nir_instr *instr, struct cse_state *state)
-{
- if (!nir_instr_can_cse(instr))
- return;
+ bool progress = false;
- for (struct exec_node *node = instr->node.prev;
- !exec_node_is_head_sentinel(node); node = node->prev) {
- nir_instr *other = exec_node_data(nir_instr, node, node);
- if (nir_instrs_equal(instr, other)) {
- nir_ssa_def *other_def = nir_instr_get_dest_ssa_def(other);
- nir_ssa_def_rewrite_uses(nir_instr_get_dest_ssa_def(instr),
- nir_src_for_ssa(other_def),
- state->mem_ctx);
+ nir_foreach_instr_safe(block, instr) {
+ if (nir_instr_set_add_or_rewrite(instr_set, instr)) {
+ progress = true;
nir_instr_remove(instr);
- state->progress = true;
- return;
}
}
- for (nir_block *block = instr->block->imm_dom;
- block != NULL; block = block->imm_dom) {
- nir_foreach_instr_reverse(block, other) {
- if (nir_instrs_equal(instr, other)) {
- nir_ssa_def *other_def = nir_instr_get_dest_ssa_def(other);
- nir_ssa_def_rewrite_uses(nir_instr_get_dest_ssa_def(instr),
- nir_src_for_ssa(other_def),
- state->mem_ctx);
- nir_instr_remove(instr);
- state->progress = true;
- return;
- }
- }
+ for (unsigned i = 0; i < block->num_dom_children; i++) {
+ nir_block *child = block->dom_children[i];
+ progress |= cse_block(child, instr_set);
}
-}
-
-static bool
-nir_opt_cse_block(nir_block *block, void *void_state)
-{
- struct cse_state *state = void_state;
- nir_foreach_instr_safe(block, instr)
- nir_opt_cse_instr(instr, state);
+ nir_foreach_instr(block, instr)
+ nir_instr_set_remove(instr_set, instr);
- return true;
+ return progress;
}
static bool
nir_opt_cse_impl(nir_function_impl *impl)
{
- struct cse_state state;
-
- state.mem_ctx = ralloc_parent(impl);
- state.progress = false;
+ struct set *instr_set = nir_instr_set_create(NULL);
nir_metadata_require(impl, nir_metadata_dominance);
- nir_foreach_block(impl, nir_opt_cse_block, &state);
+ bool progress = cse_block(nir_start_block(impl), instr_set);
- if (state.progress)
+ if (progress)
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance);
- return state.progress;
+ nir_instr_set_destroy(instr_set);
+ return progress;
}
bool
return progress;
}
+
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