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authorJason Ekstrand <[email protected]>2018-10-19 21:42:22 -0500
committerJason Ekstrand <[email protected]>2018-10-26 11:45:29 -0500
commita3b4cb34589e2f1a6898e88c8d9686cc3e133de3 (patch)
treeeffd36592820b704e539237cc1fd8a55c2456278 /src/compiler
parent4cd8a58595969e38254aeb0306b2408f80795700 (diff)
nir/opt_if: Rework condition propagation
Instead of doing our own constant folding, we just emit instructions and let constant folding happen. This is substantially simpler and lets us use the nir_imm_bool helper instead of dealing with the const_value's ourselves. Reviewed-by: Ian Romanick <[email protected]> Reviewed-by: Timothy Arceri <[email protected]>
Diffstat (limited to 'src/compiler')
-rw-r--r--src/compiler/nir/nir_opt_if.c91
1 files changed, 30 insertions, 61 deletions
diff --git a/src/compiler/nir/nir_opt_if.c b/src/compiler/nir/nir_opt_if.c
index fb161f1c4fd..72a7285c1ea 100644
--- a/src/compiler/nir/nir_opt_if.c
+++ b/src/compiler/nir/nir_opt_if.c
@@ -376,31 +376,15 @@ opt_if_loop_terminator(nir_if *nif)
return true;
}
-static void
-replace_if_condition_use_with_const(nir_builder *b, nir_src *use,
- nir_const_value nir_boolean,
- bool if_condition)
-{
- /* Create const */
- nir_ssa_def *const_def = nir_build_imm(b, 1, 32, nir_boolean);
-
- /* Rewrite use to use const */
- nir_src new_src = nir_src_for_ssa(const_def);
- if (if_condition)
- nir_if_rewrite_condition(use->parent_if, new_src);
- else
- nir_instr_rewrite_src(use->parent_instr, use, new_src);
-}
-
static bool
-evaluate_if_condition(nir_if *nif, nir_cursor cursor, uint32_t *value)
+evaluate_if_condition(nir_if *nif, nir_cursor cursor, bool *value)
{
nir_block *use_block = nir_cursor_current_block(cursor);
if (nir_block_dominates(nir_if_first_then_block(nif), use_block)) {
- *value = NIR_TRUE;
+ *value = true;
return true;
} else if (nir_block_dominates(nir_if_first_else_block(nif), use_block)) {
- *value = NIR_FALSE;
+ *value = false;
return true;
} else {
return false;
@@ -459,52 +443,31 @@ propagate_condition_eval(nir_builder *b, nir_if *nif, nir_src *use_src,
nir_src *alu_use, nir_alu_instr *alu,
bool is_if_condition)
{
- bool progress = false;
+ bool bool_value;
+ if (!evaluate_if_condition(nif, b->cursor, &bool_value))
+ return false;
- nir_const_value bool_value;
b->cursor = nir_before_src(alu_use, is_if_condition);
- if (nir_op_infos[alu->op].num_inputs == 1) {
- assert(alu->op == nir_op_inot || alu->op == nir_op_b2i);
-
- if (evaluate_if_condition(nif, b->cursor, &bool_value.u32[0])) {
- assert(nir_src_bit_size(alu->src[0].src) == 32);
-
- nir_const_value result =
- nir_eval_const_opcode(alu->op, 1, 32, &bool_value);
- replace_if_condition_use_with_const(b, alu_use, result,
- is_if_condition);
- progress = true;
+ nir_ssa_def *def[2] = { };
+ for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) {
+ if (alu->src[i].src.ssa == use_src->ssa) {
+ def[i] = nir_imm_bool(b, bool_value);
+ } else {
+ def[i] = alu->src[i].src.ssa;
}
- } else {
- assert(alu->op == nir_op_ior || alu->op == nir_op_iand);
-
- if (evaluate_if_condition(nif, b->cursor, &bool_value.u32[0])) {
- nir_ssa_def *def[2];
- for (unsigned i = 0; i < 2; i++) {
- if (alu->src[i].src.ssa == use_src->ssa) {
- def[i] = nir_build_imm(b, 1, 32, bool_value);
- } else {
- def[i] = alu->src[i].src.ssa;
- }
- }
-
- nir_ssa_def *nalu =
- nir_build_alu(b, alu->op, def[0], def[1], NULL, NULL);
-
- /* Rewrite use to use new alu instruction */
- nir_src new_src = nir_src_for_ssa(nalu);
+ }
+ nir_ssa_def *nalu = nir_build_alu(b, alu->op, def[0], def[1], NULL, NULL);
- if (is_if_condition)
- nir_if_rewrite_condition(alu_use->parent_if, new_src);
- else
- nir_instr_rewrite_src(alu_use->parent_instr, alu_use, new_src);
+ /* Rewrite use to use new alu instruction */
+ nir_src new_src = nir_src_for_ssa(nalu);
- progress = true;
- }
- }
+ if (is_if_condition)
+ nir_if_rewrite_condition(alu_use->parent_if, new_src);
+ else
+ nir_instr_rewrite_src(alu_use->parent_instr, alu_use, new_src);
- return progress;
+ return true;
}
static bool
@@ -526,11 +489,17 @@ evaluate_condition_use(nir_builder *b, nir_if *nif, nir_src *use_src,
{
bool progress = false;
- nir_const_value value;
b->cursor = nir_before_src(use_src, is_if_condition);
- if (evaluate_if_condition(nif, b->cursor, &value.u32[0])) {
- replace_if_condition_use_with_const(b, use_src, value, is_if_condition);
+ bool bool_value;
+ if (evaluate_if_condition(nif, b->cursor, &bool_value)) {
+ /* Rewrite use to use const */
+ nir_src imm_src = nir_src_for_ssa(nir_imm_bool(b, bool_value));
+ if (is_if_condition)
+ nir_if_rewrite_condition(use_src->parent_if, imm_src);
+ else
+ nir_instr_rewrite_src(use_src->parent_instr, use_src, imm_src);
+
progress = true;
}