nir/opt_peephole_select: respect selection_control when collapsing ifs

Totals from 34 (0.02% of 138013) affected shaders (RAVEN):
CodeSize: 625888 -> 626336 (+0.07%); split: -0.00%, +0.08%
Instrs: 124121 -> 124229 (+0.09%); split: -0.00%, +0.09%
Cycles: 1403072 -> 1403588 (+0.04%); split: -0.01%, +0.04%
VMEM: 5308 -> 5364 (+1.06%); split: +1.07%, -0.02%
Copies: 12773 -> 12838 (+0.51%); split: -0.08%, +0.59%
Branches: 5758 -> 5801 (+0.75%); split: -0.21%, +0.96%

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7478>
This commit is contained in:
Daniel Schürmann 2020-11-06 23:44:06 +01:00 committed by Marge Bot
parent 28395407eb
commit 1c17223c02

View file

@ -242,6 +242,10 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
if (if_stmt->cf_node.parent->type != nir_cf_node_if)
return false;
nir_if *parent_if = nir_cf_node_as_if(if_stmt->cf_node.parent);
if (parent_if->control == nir_selection_control_dont_flatten)
return false;
/* check if the else block is empty */
if (!nir_cf_list_is_empty_block(&if_stmt->else_list))
return false;
@ -252,7 +256,6 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
/* the nested if has to be the only cf_node:
* i.e. <block> <if_stmt> <block> */
nir_if *parent_if = nir_cf_node_as_if(if_stmt->cf_node.parent);
if (exec_list_length(&parent_if->then_list) != 3)
return false;
@ -268,6 +271,9 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
/* check if all outer phis become trivial after merging the ifs */
nir_foreach_instr(instr, last) {
if (parent_if->control == nir_selection_control_flatten)
break;
nir_phi_instr *phi = nir_instr_as_phi(instr);
nir_phi_src *else_src =
nir_phi_get_src_from_block(phi, nir_if_first_else_block(if_stmt));
@ -282,6 +288,12 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
}
}
if (parent_if->control == nir_selection_control_flatten) {
/* Override driver defaults */
indirect_load_ok = true;
expensive_alu_ok = true;
}
/* check if the block before the nested if matches the requirements */
nir_block *first = nir_if_first_then_block(parent_if);
unsigned count = 0;
@ -289,18 +301,21 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
indirect_load_ok, expensive_alu_ok))
return false;
if (count > limit)
if (count > limit && parent_if->control != nir_selection_control_flatten)
return false;
/* trivialize succeeding phis */
nir_foreach_instr(instr, last) {
nir_phi_instr *phi = nir_instr_as_phi(instr);
nir_phi_src *else_src =
nir_phi_get_src_from_block(phi, nir_if_first_else_block(if_stmt));
nir_foreach_use_safe(src, &phi->dest.ssa) {
nir_phi_src *phi_src =
nir_phi_get_src_from_block(nir_instr_as_phi(src->parent_instr),
nir_if_first_else_block(parent_if));
nir_instr_rewrite_src(src->parent_instr, &phi_src->src,
nir_src_for_ssa(&phi->dest.ssa));
if (phi_src->src.ssa == else_src->src.ssa)
nir_instr_rewrite_src(src->parent_instr, &phi_src->src,
nir_src_for_ssa(&phi->dest.ssa));
}
}