static bool
constant_fold_intrinsic_instr(nir_intrinsic_instr *instr)
{
bool progress = false;
if (instr->intrinsic == nir_intrinsic_discard_if &&
nir_src_is_const(instr->src[0])) {
if (nir_src_as_bool(instr->src[0])) {
/* This method of getting a nir_shader * from a nir_instr is
* admittedly gross, but given the rarity of hitting this case I think
* it's preferable to plumbing an otherwise unused nir_shader *
* parameter through four functions to get here.
*/
nir_cf_node *cf_node = &instr->instr.block->cf_node;
nir_function_impl *impl = nir_cf_node_get_function(cf_node);
nir_shader *shader = impl->function->shader;
nir_intrinsic_instr *discard =
nir_intrinsic_instr_create(shader, nir_intrinsic_discard);
nir_instr_insert_before(&instr->instr, &discard->instr);
nir_instr_remove(&instr->instr);
progress = true;
} else {
/* We're not discarding, just delete the instruction */
nir_instr_remove(&instr->instr);
progress = true;
}
}
return progress;
}
static nir_src
get_deref_reg_src(nir_deref_instr *deref, struct locals_to_regs_state *state)
{
nir_builder *b = &state->builder;
nir_src src;
src.is_ssa = false;
src.reg.reg = get_reg_for_deref(deref, state);
src.reg.base_offset = 0;
src.reg.indirect = NULL;
/* It is possible for a user to create a shader that has an array with a
* single element and then proceed to access it indirectly. Indirectly
* accessing a non-array register is not allowed in NIR. In order to
* handle this case we just convert it to a direct reference.
*/
if (src.reg.reg->num_array_elems == 0)
return src;
unsigned inner_array_size = 1;
for (const nir_deref_instr *d = deref; d; d = nir_deref_instr_parent(d)) {
if (d->deref_type != nir_deref_type_array)
continue;
if (nir_src_is_const(d->arr.index) && !src.reg.indirect) {
src.reg.base_offset += nir_src_as_uint(d->arr.index) *
inner_array_size;
} else {
if (src.reg.indirect) {
assert(src.reg.base_offset == 0);
} else {
src.reg.indirect = ralloc(b->shader, nir_src);
*src.reg.indirect =
nir_src_for_ssa(nir_imm_int(b, src.reg.base_offset));
src.reg.base_offset = 0;
}
assert(src.reg.indirect->is_ssa);
nir_ssa_def *index = nir_i2i(b, nir_ssa_for_src(b, d->arr.index, 1), 32);
src.reg.indirect->ssa =
nir_iadd(b, src.reg.indirect->ssa,
nir_imul(b, index, nir_imm_int(b, inner_array_size)));
}
inner_array_size *= glsl_get_length(nir_deref_instr_parent(d)->type);
}
return src;
}
static unsigned
get_io_offset(nir_deref_instr *deref, bool is_vertex_input)
{
unsigned offset = 0;
for (nir_deref_instr *d = deref; d; d = nir_deref_instr_parent(d)) {
if (d->deref_type == nir_deref_type_array) {
if (!nir_src_is_const(d->arr.index))
return -1;
offset += glsl_count_attribute_slots(d->type, is_vertex_input) *
nir_src_as_uint(d->arr.index);
}
/* TODO: we can get the offset for structs here see nir_lower_io() */
}
return offset;
}