2 * Copyright © 2014 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Jason Ekstrand (jason@jlekstrand.net)
29 #include "nir_builder.h"
30 #include "nir_deref.h"
31 #include "nir_phi_builder.h"
36 struct deref_node
*parent
;
37 const struct glsl_type
*type
;
41 /* Only valid for things that end up in the direct list.
42 * Note that multiple nir_deref_instrs may correspond to this node, but
43 * they will all be equivalent, so any is as good as the other.
46 struct exec_node direct_derefs_link
;
52 struct nir_phi_builder_value
*pb_value
;
54 /* True if this node is fully direct. If set, it must be in the children
55 * array of its parent.
59 /* Set on a root node for a variable to indicate that variable is used by a
60 * cast or passed through some other sequence of instructions that are not
65 struct deref_node
*wildcard
;
66 struct deref_node
*indirect
;
67 struct deref_node
*children
[0];
70 #define UNDEF_NODE ((struct deref_node *)(uintptr_t)1)
72 struct lower_variables_state
{
75 nir_function_impl
*impl
;
77 /* A hash table mapping variables to deref_node data */
78 struct hash_table
*deref_var_nodes
;
80 /* A hash table mapping fully-qualified direct dereferences, i.e.
81 * dereferences with no indirect or wildcard array dereferences, to
84 * At the moment, we only lower loads, stores, and copies that can be
85 * trivially lowered to loads and stores, i.e. copies with no indirects
86 * and no wildcards. If a part of a variable that is being loaded from
87 * and/or stored into is also involved in a copy operation with
88 * wildcards, then we lower that copy operation to loads and stores, but
89 * otherwise we leave copies with wildcards alone. Since the only derefs
90 * used in these loads, stores, and trivial copies are ones with no
91 * wildcards and no indirects, these are precisely the derefs that we
92 * can actually consider lowering.
94 struct exec_list direct_deref_nodes
;
96 /* Controls whether get_deref_node will add variables to the
97 * direct_deref_nodes table. This is turned on when we are initially
98 * scanning for load/store instructions. It is then turned off so we
99 * don't accidentally change the direct_deref_nodes table while we're
100 * iterating throug it.
102 bool add_to_direct_deref_nodes
;
104 struct nir_phi_builder
*phi_builder
;
107 static struct deref_node
*
108 deref_node_create(struct deref_node
*parent
,
109 const struct glsl_type
*type
,
110 bool is_direct
, void *mem_ctx
)
112 size_t size
= sizeof(struct deref_node
) +
113 glsl_get_length(type
) * sizeof(struct deref_node
*);
115 struct deref_node
*node
= rzalloc_size(mem_ctx
, size
);
117 node
->parent
= parent
;
118 exec_node_init(&node
->direct_derefs_link
);
119 node
->is_direct
= is_direct
;
124 /* Returns the deref node associated with the given variable. This will be
125 * the root of the tree representing all of the derefs of the given variable.
127 static struct deref_node
*
128 get_deref_node_for_var(nir_variable
*var
, struct lower_variables_state
*state
)
130 struct deref_node
*node
;
132 struct hash_entry
*var_entry
=
133 _mesa_hash_table_search(state
->deref_var_nodes
, var
);
136 return var_entry
->data
;
138 node
= deref_node_create(NULL
, var
->type
, true, state
->dead_ctx
);
139 _mesa_hash_table_insert(state
->deref_var_nodes
, var
, node
);
144 /* Gets the deref_node for the given deref chain and creates it if it
145 * doesn't yet exist. If the deref is fully-qualified and direct and
146 * state->add_to_direct_deref_nodes is true, it will be added to the hash
147 * table of of fully-qualified direct derefs.
149 static struct deref_node
*
150 get_deref_node_recur(nir_deref_instr
*deref
,
151 struct lower_variables_state
*state
)
153 if (deref
->deref_type
== nir_deref_type_var
)
154 return get_deref_node_for_var(deref
->var
, state
);
156 if (deref
->deref_type
== nir_deref_type_cast
)
159 struct deref_node
*parent
=
160 get_deref_node_recur(nir_deref_instr_parent(deref
), state
);
164 if (parent
== UNDEF_NODE
)
167 switch (deref
->deref_type
) {
168 case nir_deref_type_struct
:
169 assert(glsl_type_is_struct_or_ifc(parent
->type
));
170 assert(deref
->strct
.index
< glsl_get_length(parent
->type
));
172 if (parent
->children
[deref
->strct
.index
] == NULL
) {
173 parent
->children
[deref
->strct
.index
] =
174 deref_node_create(parent
, deref
->type
, parent
->is_direct
,
178 return parent
->children
[deref
->strct
.index
];
180 case nir_deref_type_array
: {
181 if (nir_src_is_const(deref
->arr
.index
)) {
182 uint32_t index
= nir_src_as_uint(deref
->arr
.index
);
183 /* This is possible if a loop unrolls and generates an
184 * out-of-bounds offset. We need to handle this at least
185 * somewhat gracefully.
187 if (index
>= glsl_get_length(parent
->type
))
190 if (parent
->children
[index
] == NULL
) {
191 parent
->children
[index
] =
192 deref_node_create(parent
, deref
->type
, parent
->is_direct
,
196 return parent
->children
[index
];
198 if (parent
->indirect
== NULL
) {
200 deref_node_create(parent
, deref
->type
, false, state
->dead_ctx
);
203 return parent
->indirect
;
208 case nir_deref_type_array_wildcard
:
209 if (parent
->wildcard
== NULL
) {
211 deref_node_create(parent
, deref
->type
, false, state
->dead_ctx
);
214 return parent
->wildcard
;
217 unreachable("Invalid deref type");
221 static struct deref_node
*
222 get_deref_node(nir_deref_instr
*deref
, struct lower_variables_state
*state
)
224 /* This pass only works on local variables. Just ignore any derefs with
227 if (deref
->mode
!= nir_var_function_temp
)
230 struct deref_node
*node
= get_deref_node_recur(deref
, state
);
234 /* Insert the node in the direct derefs list. We only do this if it's not
235 * already in the list and we only bother for deref nodes which are used
236 * directly in a load or store.
238 if (node
!= UNDEF_NODE
&& node
->is_direct
&&
239 state
->add_to_direct_deref_nodes
&&
240 node
->direct_derefs_link
.next
== NULL
) {
241 nir_deref_path_init(&node
->path
, deref
, state
->dead_ctx
);
242 assert(deref
->var
!= NULL
);
243 exec_list_push_tail(&state
->direct_deref_nodes
,
244 &node
->direct_derefs_link
);
250 /* \sa foreach_deref_node_match */
252 foreach_deref_node_worker(struct deref_node
*node
, nir_deref_instr
**path
,
253 void (* cb
)(struct deref_node
*node
,
254 struct lower_variables_state
*state
),
255 struct lower_variables_state
*state
)
262 switch ((*path
)->deref_type
) {
263 case nir_deref_type_struct
:
264 if (node
->children
[(*path
)->strct
.index
]) {
265 foreach_deref_node_worker(node
->children
[(*path
)->strct
.index
],
266 path
+ 1, cb
, state
);
270 case nir_deref_type_array
: {
271 uint32_t index
= nir_src_as_uint((*path
)->arr
.index
);
273 if (node
->children
[index
]) {
274 foreach_deref_node_worker(node
->children
[index
],
275 path
+ 1, cb
, state
);
278 if (node
->wildcard
) {
279 foreach_deref_node_worker(node
->wildcard
,
280 path
+ 1, cb
, state
);
286 unreachable("Unsupported deref type");
290 /* Walks over every "matching" deref_node and calls the callback. A node
291 * is considered to "match" if either refers to that deref or matches up t
292 * a wildcard. In other words, the following would match a[6].foo[3].bar:
299 * The given deref must be a full-length and fully qualified (no wildcards
300 * or indirects) deref chain.
303 foreach_deref_node_match(nir_deref_path
*path
,
304 void (* cb
)(struct deref_node
*node
,
305 struct lower_variables_state
*state
),
306 struct lower_variables_state
*state
)
308 assert(path
->path
[0]->deref_type
== nir_deref_type_var
);
309 struct deref_node
*node
= get_deref_node_for_var(path
->path
[0]->var
, state
);
314 foreach_deref_node_worker(node
, &path
->path
[1], cb
, state
);
317 /* \sa deref_may_be_aliased */
319 path_may_be_aliased_node(struct deref_node
*node
, nir_deref_instr
**path
,
320 struct lower_variables_state
*state
)
325 switch ((*path
)->deref_type
) {
326 case nir_deref_type_struct
:
327 if (node
->children
[(*path
)->strct
.index
]) {
328 return path_may_be_aliased_node(node
->children
[(*path
)->strct
.index
],
334 case nir_deref_type_array
: {
335 if (!nir_src_is_const((*path
)->arr
.index
))
338 uint32_t index
= nir_src_as_uint((*path
)->arr
.index
);
340 /* If there is an indirect at this level, we're aliased. */
344 if (node
->children
[index
] &&
345 path_may_be_aliased_node(node
->children
[index
],
349 if (node
->wildcard
&&
350 path_may_be_aliased_node(node
->wildcard
, path
+ 1, state
))
357 unreachable("Unsupported deref type");
361 /* Returns true if there are no indirects that can ever touch this deref.
363 * For example, if the given deref is a[6].foo, then any uses of a[i].foo
364 * would cause this to return false, but a[i].bar would not affect it
365 * because it's a different structure member. A var_copy involving of
366 * a[*].bar also doesn't affect it because that can be lowered to entirely
367 * direct load/stores.
369 * We only support asking this question about fully-qualified derefs.
370 * Obviously, it's pointless to ask this about indirects, but we also
371 * rule-out wildcards. Handling Wildcard dereferences would involve
372 * checking each array index to make sure that there aren't any indirect
376 path_may_be_aliased(nir_deref_path
*path
,
377 struct lower_variables_state
*state
)
379 assert(path
->path
[0]->deref_type
== nir_deref_type_var
);
380 nir_variable
*var
= path
->path
[0]->var
;
381 struct deref_node
*var_node
= get_deref_node_for_var(var
, state
);
383 /* First see if this variable is ever used by anything other than a
384 * load/store. If there's even so much as a cast in the way, we have to
385 * assume aliasing and bail.
387 if (var_node
->has_complex_use
)
390 return path_may_be_aliased_node(var_node
, &path
->path
[1], state
);
394 register_complex_use(nir_deref_instr
*deref
,
395 struct lower_variables_state
*state
)
397 assert(deref
->deref_type
== nir_deref_type_var
);
398 struct deref_node
*node
= get_deref_node_for_var(deref
->var
, state
);
402 node
->has_complex_use
= true;
406 register_load_instr(nir_intrinsic_instr
*load_instr
,
407 struct lower_variables_state
*state
)
409 nir_deref_instr
*deref
= nir_src_as_deref(load_instr
->src
[0]);
410 struct deref_node
*node
= get_deref_node(deref
, state
);
411 if (node
== NULL
|| node
== UNDEF_NODE
)
414 if (node
->loads
== NULL
)
415 node
->loads
= _mesa_pointer_set_create(state
->dead_ctx
);
417 _mesa_set_add(node
->loads
, load_instr
);
421 register_store_instr(nir_intrinsic_instr
*store_instr
,
422 struct lower_variables_state
*state
)
424 nir_deref_instr
*deref
= nir_src_as_deref(store_instr
->src
[0]);
425 struct deref_node
*node
= get_deref_node(deref
, state
);
426 if (node
== NULL
|| node
== UNDEF_NODE
)
429 if (node
->stores
== NULL
)
430 node
->stores
= _mesa_pointer_set_create(state
->dead_ctx
);
432 _mesa_set_add(node
->stores
, store_instr
);
436 register_copy_instr(nir_intrinsic_instr
*copy_instr
,
437 struct lower_variables_state
*state
)
439 for (unsigned idx
= 0; idx
< 2; idx
++) {
440 nir_deref_instr
*deref
= nir_src_as_deref(copy_instr
->src
[idx
]);
441 struct deref_node
*node
= get_deref_node(deref
, state
);
442 if (node
== NULL
|| node
== UNDEF_NODE
)
445 if (node
->copies
== NULL
)
446 node
->copies
= _mesa_pointer_set_create(state
->dead_ctx
);
448 _mesa_set_add(node
->copies
, copy_instr
);
453 register_variable_uses(nir_function_impl
*impl
,
454 struct lower_variables_state
*state
)
456 nir_foreach_block(block
, impl
) {
457 nir_foreach_instr_safe(instr
, block
) {
458 switch (instr
->type
) {
459 case nir_instr_type_deref
: {
460 nir_deref_instr
*deref
= nir_instr_as_deref(instr
);
462 if (deref
->deref_type
== nir_deref_type_var
&&
463 nir_deref_instr_has_complex_use(deref
))
464 register_complex_use(deref
, state
);
469 case nir_instr_type_intrinsic
: {
470 nir_intrinsic_instr
*intrin
= nir_instr_as_intrinsic(instr
);
472 switch (intrin
->intrinsic
) {
473 case nir_intrinsic_load_deref
:
474 register_load_instr(intrin
, state
);
477 case nir_intrinsic_store_deref
:
478 register_store_instr(intrin
, state
);
481 case nir_intrinsic_copy_deref
:
482 register_copy_instr(intrin
, state
);
498 /* Walks over all of the copy instructions to or from the given deref_node
499 * and lowers them to load/store intrinsics.
502 lower_copies_to_load_store(struct deref_node
*node
,
503 struct lower_variables_state
*state
)
509 nir_builder_init(&b
, state
->impl
);
511 set_foreach(node
->copies
, copy_entry
) {
512 nir_intrinsic_instr
*copy
= (void *)copy_entry
->key
;
514 nir_lower_deref_copy_instr(&b
, copy
);
516 for (unsigned i
= 0; i
< 2; ++i
) {
517 nir_deref_instr
*arg_deref
= nir_src_as_deref(copy
->src
[i
]);
518 struct deref_node
*arg_node
= get_deref_node(arg_deref
, state
);
520 /* Only bother removing copy entries for other nodes */
521 if (arg_node
== NULL
|| arg_node
== node
)
524 struct set_entry
*arg_entry
= _mesa_set_search(arg_node
->copies
, copy
);
526 _mesa_set_remove(arg_node
->copies
, arg_entry
);
529 nir_instr_remove(©
->instr
);
535 /* Performs variable renaming
537 * This algorithm is very similar to the one outlined in "Efficiently
538 * Computing Static Single Assignment Form and the Control Dependence
539 * Graph" by Cytron et al. The primary difference is that we only put one
540 * SSA def on the stack per block.
543 rename_variables(struct lower_variables_state
*state
)
546 nir_builder_init(&b
, state
->impl
);
548 nir_foreach_block(block
, state
->impl
) {
549 nir_foreach_instr_safe(instr
, block
) {
550 if (instr
->type
!= nir_instr_type_intrinsic
)
553 nir_intrinsic_instr
*intrin
= nir_instr_as_intrinsic(instr
);
555 switch (intrin
->intrinsic
) {
556 case nir_intrinsic_load_deref
: {
557 nir_deref_instr
*deref
= nir_src_as_deref(intrin
->src
[0]);
558 if (deref
->mode
!= nir_var_function_temp
)
561 struct deref_node
*node
= get_deref_node(deref
, state
);
565 if (node
== UNDEF_NODE
) {
566 /* If we hit this path then we are referencing an invalid
567 * value. Most likely, we unrolled something and are
568 * reading past the end of some array. In any case, this
569 * should result in an undefined value.
571 nir_ssa_undef_instr
*undef
=
572 nir_ssa_undef_instr_create(state
->shader
,
573 intrin
->num_components
,
574 intrin
->dest
.ssa
.bit_size
);
576 nir_instr_insert_before(&intrin
->instr
, &undef
->instr
);
577 nir_instr_remove(&intrin
->instr
);
579 nir_ssa_def_rewrite_uses(&intrin
->dest
.ssa
,
580 nir_src_for_ssa(&undef
->def
));
584 if (!node
->lower_to_ssa
)
587 nir_alu_instr
*mov
= nir_alu_instr_create(state
->shader
,
589 mov
->src
[0].src
= nir_src_for_ssa(
590 nir_phi_builder_value_get_block_def(node
->pb_value
, block
));
591 for (unsigned i
= intrin
->num_components
; i
< NIR_MAX_VEC_COMPONENTS
; i
++)
592 mov
->src
[0].swizzle
[i
] = 0;
594 assert(intrin
->dest
.is_ssa
);
596 mov
->dest
.write_mask
= (1 << intrin
->num_components
) - 1;
597 nir_ssa_dest_init(&mov
->instr
, &mov
->dest
.dest
,
598 intrin
->num_components
,
599 intrin
->dest
.ssa
.bit_size
, NULL
);
601 nir_instr_insert_before(&intrin
->instr
, &mov
->instr
);
602 nir_instr_remove(&intrin
->instr
);
604 nir_ssa_def_rewrite_uses(&intrin
->dest
.ssa
,
605 nir_src_for_ssa(&mov
->dest
.dest
.ssa
));
609 case nir_intrinsic_store_deref
: {
610 nir_deref_instr
*deref
= nir_src_as_deref(intrin
->src
[0]);
611 if (deref
->mode
!= nir_var_function_temp
)
614 struct deref_node
*node
= get_deref_node(deref
, state
);
618 assert(intrin
->src
[1].is_ssa
);
619 nir_ssa_def
*value
= intrin
->src
[1].ssa
;
621 if (node
== UNDEF_NODE
) {
622 /* Probably an out-of-bounds array store. That should be a
624 nir_instr_remove(&intrin
->instr
);
628 if (!node
->lower_to_ssa
)
631 assert(intrin
->num_components
==
632 glsl_get_vector_elements(node
->type
));
634 nir_ssa_def
*new_def
;
635 b
.cursor
= nir_before_instr(&intrin
->instr
);
637 unsigned wrmask
= nir_intrinsic_write_mask(intrin
);
638 if (wrmask
== (1 << intrin
->num_components
) - 1) {
639 /* Whole variable store - just copy the source. Note that
640 * intrin->num_components and value->num_components
643 unsigned swiz
[NIR_MAX_VEC_COMPONENTS
];
644 for (unsigned i
= 0; i
< NIR_MAX_VEC_COMPONENTS
; i
++)
645 swiz
[i
] = i
< intrin
->num_components
? i
: 0;
647 new_def
= nir_swizzle(&b
, value
, swiz
,
648 intrin
->num_components
);
650 nir_ssa_def
*old_def
=
651 nir_phi_builder_value_get_block_def(node
->pb_value
, block
);
652 /* For writemasked store_var intrinsics, we combine the newly
653 * written values with the existing contents of unwritten
654 * channels, creating a new SSA value for the whole vector.
656 nir_ssa_def
*srcs
[NIR_MAX_VEC_COMPONENTS
];
657 for (unsigned i
= 0; i
< intrin
->num_components
; i
++) {
658 if (wrmask
& (1 << i
)) {
659 srcs
[i
] = nir_channel(&b
, value
, i
);
661 srcs
[i
] = nir_channel(&b
, old_def
, i
);
664 new_def
= nir_vec(&b
, srcs
, intrin
->num_components
);
667 assert(new_def
->num_components
== intrin
->num_components
);
669 nir_phi_builder_value_set_block_def(node
->pb_value
, block
, new_def
);
670 nir_instr_remove(&intrin
->instr
);
683 /** Implements a pass to lower variable uses to SSA values
685 * This path walks the list of instructions and tries to lower as many
686 * local variable load/store operations to SSA defs and uses as it can.
687 * The process involves four passes:
689 * 1) Iterate over all of the instructions and mark where each local
690 * variable deref is used in a load, store, or copy. While we're at
691 * it, we keep track of all of the fully-qualified (no wildcards) and
692 * fully-direct references we see and store them in the
693 * direct_deref_nodes hash table.
695 * 2) Walk over the list of fully-qualified direct derefs generated in
696 * the previous pass. For each deref, we determine if it can ever be
697 * aliased, i.e. if there is an indirect reference anywhere that may
698 * refer to it. If it cannot be aliased, we mark it for lowering to an
699 * SSA value. At this point, we lower any var_copy instructions that
700 * use the given deref to load/store operations.
702 * 3) Walk over the list of derefs we plan to lower to SSA values and
703 * insert phi nodes as needed.
705 * 4) Perform "variable renaming" by replacing the load/store instructions
706 * with SSA definitions and SSA uses.
709 nir_lower_vars_to_ssa_impl(nir_function_impl
*impl
)
711 struct lower_variables_state state
;
713 state
.shader
= impl
->function
->shader
;
714 state
.dead_ctx
= ralloc_context(state
.shader
);
717 state
.deref_var_nodes
= _mesa_pointer_hash_table_create(state
.dead_ctx
);
718 exec_list_make_empty(&state
.direct_deref_nodes
);
720 /* Build the initial deref structures and direct_deref_nodes table */
721 state
.add_to_direct_deref_nodes
= true;
723 register_variable_uses(impl
, &state
);
725 bool progress
= false;
727 nir_metadata_require(impl
, nir_metadata_block_index
);
729 /* We're about to iterate through direct_deref_nodes. Don't modify it. */
730 state
.add_to_direct_deref_nodes
= false;
732 foreach_list_typed_safe(struct deref_node
, node
, direct_derefs_link
,
733 &state
.direct_deref_nodes
) {
734 nir_deref_path
*path
= &node
->path
;
736 assert(path
->path
[0]->deref_type
== nir_deref_type_var
);
738 /* We don't build deref nodes for non-local variables */
739 assert(path
->path
[0]->var
->data
.mode
== nir_var_function_temp
);
741 if (path_may_be_aliased(path
, &state
)) {
742 exec_node_remove(&node
->direct_derefs_link
);
746 node
->lower_to_ssa
= true;
749 foreach_deref_node_match(path
, lower_copies_to_load_store
, &state
);
753 nir_metadata_preserve(impl
, nir_metadata_all
);
757 nir_metadata_require(impl
, nir_metadata_dominance
);
759 /* We may have lowered some copy instructions to load/store
760 * instructions. The uses from the copy instructions hav already been
761 * removed but we need to rescan to ensure that the uses from the newly
762 * added load/store instructions are registered. We need this
763 * information for phi node insertion below.
765 register_variable_uses(impl
, &state
);
767 state
.phi_builder
= nir_phi_builder_create(state
.impl
);
769 BITSET_WORD
*store_blocks
=
770 ralloc_array(state
.dead_ctx
, BITSET_WORD
,
771 BITSET_WORDS(state
.impl
->num_blocks
));
772 foreach_list_typed(struct deref_node
, node
, direct_derefs_link
,
773 &state
.direct_deref_nodes
) {
774 if (!node
->lower_to_ssa
)
777 memset(store_blocks
, 0,
778 BITSET_WORDS(state
.impl
->num_blocks
) * sizeof(*store_blocks
));
780 assert(node
->path
.path
[0]->var
->constant_initializer
== NULL
&&
781 node
->path
.path
[0]->var
->pointer_initializer
== NULL
);
784 set_foreach(node
->stores
, store_entry
) {
785 nir_intrinsic_instr
*store
=
786 (nir_intrinsic_instr
*)store_entry
->key
;
787 BITSET_SET(store_blocks
, store
->instr
.block
->index
);
792 nir_phi_builder_add_value(state
.phi_builder
,
793 glsl_get_vector_elements(node
->type
),
794 glsl_get_bit_size(node
->type
),
798 rename_variables(&state
);
800 nir_phi_builder_finish(state
.phi_builder
);
802 nir_metadata_preserve(impl
, nir_metadata_block_index
|
803 nir_metadata_dominance
);
805 ralloc_free(state
.dead_ctx
);
811 nir_lower_vars_to_ssa(nir_shader
*shader
)
813 bool progress
= false;
815 nir_foreach_function(function
, shader
) {
817 progress
|= nir_lower_vars_to_ssa_impl(function
->impl
);