---
src/compiler/nir/nir_remove_dead_variables.c | 99 ++++++++++++++++++++++++++++
1 file changed, 99 insertions(+)
diff --git a/src/compiler/nir/nir_remove_dead_variables.c
b/src/compiler/nir/nir_remove_dead_variables.c
index eff66f9..6b1927f 100644
--- a/src/compiler/nir/nir_remove_dead_variables.c
+++ b/src/compiler/nir/nir_remove_dead_variables.c
@@ -27,6 +27,55 @@
#include "nir.h"
+static bool
+deref_used_for_not_store(nir_deref_instr *deref)
+{
+ nir_foreach_use(src, &deref->dest.ssa) {
+ switch (src->parent_instr->type) {
+ case nir_instr_type_deref:
+ if (deref_used_for_not_store(nir_instr_as_deref(src->parent_instr)))
+ return true;
+ break;
+
+ case nir_instr_type_intrinsic: {
+ nir_intrinsic_instr *intrin =
+ nir_instr_as_intrinsic(src->parent_instr);
+ /* The first source of copy and store intrinsics is the deref to
+ * write. Don't record those.
+ */
+ if ((intrin->intrinsic != nir_intrinsic_store_deref &&
+ intrin->intrinsic != nir_intrinsic_copy_var) ||
+ src != &intrin->src[0])
+ return true;
+ break;
+ }
+
+ default:
+ /* If it's used by any other instruction type (most likely a texture
+ * instruction), consider it used.
+ */
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void
+add_var_use_deref(nir_deref_instr *deref, struct set *live)
+{
+ if (deref->deref_type != nir_deref_type_var)
+ return;
+
+ /* If it's not a local that never escapes the shader, then any access at
+ * all means we need to keep it alive.
+ */
+ assert(deref->mode == deref->var->data.mode);
+ if (!(deref->mode & (nir_var_local | nir_var_global | nir_var_shared)) ||
+ deref_used_for_not_store(deref))
+ _mesa_set_add(live, deref->var);
+}
+
static void
add_var_use_intrinsic(nir_intrinsic_instr *instr, struct set *live,
nir_variable_mode modes)
@@ -100,6 +149,10 @@ add_var_use_shader(nir_shader *shader, struct set *live,
nir_variable_mode modes
nir_foreach_block(block, function->impl) {
nir_foreach_instr(instr, block) {
switch(instr->type) {
+ case nir_instr_type_deref:
+ add_var_use_deref(nir_instr_as_deref(instr), live);
+ break;
+
case nir_instr_type_intrinsic:
add_var_use_intrinsic(nir_instr_as_intrinsic(instr), live,
modes);
@@ -123,6 +176,33 @@ add_var_use_shader(nir_shader *shader, struct set *live,
nir_variable_mode modes
}
static void
+remove_dead_deref(nir_deref_instr *deref)
+{
+ nir_foreach_use(src, &deref->dest.ssa) {
+ switch (src->parent_instr->type) {
+ case nir_instr_type_deref:
+ remove_dead_deref(nir_instr_as_deref(src->parent_instr));
+ break;
+
+ case nir_instr_type_intrinsic: {
+ nir_intrinsic_instr *intrin =
+ nir_instr_as_intrinsic(src->parent_instr);
+
+ assert(intrin->intrinsic == nir_intrinsic_copy_deref ||
+ intrin->intrinsic == nir_intrinsic_store_deref);
+ nir_instr_remove(&intrin->instr);
+ break;
+ }
+
+ default:
+ unreachable("This must have been marked as live!");
+ }
+ }
+
+ nir_instr_remove(&deref->instr);
+}
+
+static void
remove_dead_var_writes(nir_shader *shader, struct set *live)
{
nir_foreach_function(function, shader) {
@@ -144,6 +224,25 @@ remove_dead_var_writes(nir_shader *shader, struct set
*live)
nir_instr_remove(instr);
}
}
+
+ /* We walk the list of instructions backwards because we're going to
+ * delete a deref and all of it's uses and we don't want to end up
+ * deleting stuff ahead of us.
+ */
+ nir_foreach_block_reverse(block, function->impl) {
+ nir_foreach_instr_reverse_safe(instr, block) {
+ if (instr->type != nir_instr_type_deref)
+ continue;
+
+ nir_deref_instr *deref = nir_instr_as_deref(instr);
+ if (deref->deref_type != nir_deref_type_var)
+ continue;
+
+ /* If it's been marked as dead, delete it */
+ if (deref->var->data.mode == 0)
+ remove_dead_deref(deref);
+ }
+ }
}
}
--
2.5.0.400.gff86faf
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