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nir/deref: Re-arrange variable checks in compare_deref_paths

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Instead of having a bunch of mode checks as special cases, assert that
the modes equal and then switch on the mode.  This should make the
special cases a bit easier to understand.  Handling of `a_var == b_var`
looks redundant now but it won't be in the next patch.

Tested-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: M Henning <drawoc@darkrefraction.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Cc: mesa-stable@lists.freedesktop.org
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16894>
This commit is contained in:
Jason Ekstrand
2022-06-03 15:06:46 -05:00
committed by Marge Bot
parent 130d9d80db
commit 0ad2dfe942
1 changed files with 31 additions and 20 deletions
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src/compiler/nir/nir_deref.c
+31 -20
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@@ -573,32 +573,43 @@ nir_compare_deref_paths(nir_deref_path *a_path,
return nir_derefs_may_alias_bit;
if (a_path->path[0]->deref_type == nir_deref_type_var) {
if (a_path->path[0]->var != b_path->path[0]->var) {
/* Shader and function temporaries aren't backed by memory so two
* distinct variables never alias.
*/
static const nir_variable_mode temp_var_modes =
nir_var_shader_temp | nir_var_function_temp;
if (!(a_path->path[0]->modes & ~temp_var_modes) ||
!(b_path->path[0]->modes & ~temp_var_modes))
return nir_derefs_do_not_alias;
const nir_variable *a_var = a_path->path[0]->var;
const nir_variable *b_var = b_path->path[0]->var;
/* Per SPV_KHR_workgroup_memory_explicit_layout and GL_EXT_shared_memory_block,
* shared blocks alias each other.
/* If we got here, the two variables must have the same mode. The
* only way modes_may_alias() can return true for two different modes
* is if one is global and the other ssbo. However, Global variables
* only exist in OpenCL and SSBOs don't exist there. No API allows
* both for variables.
*/
assert(a_var->data.mode == b_var->data.mode);
switch (a_var->data.mode) {
case nir_var_mem_shared:
if (a_var == b_var)
break;
/* Per SPV_KHR_workgroup_memory_explicit_layout and
* GL_EXT_shared_memory_block, shared blocks alias each other.
* We will have either all blocks or all non-blocks.
*/
if (a_path->path[0]->modes & nir_var_mem_shared &&
b_path->path[0]->modes & nir_var_mem_shared &&
(glsl_type_is_interface(a_path->path[0]->var->type) ||
glsl_type_is_interface(b_path->path[0]->var->type))) {
assert(glsl_type_is_interface(a_path->path[0]->var->type) &&
glsl_type_is_interface(b_path->path[0]->var->type));
if (glsl_type_is_interface(a_var->type) ||
glsl_type_is_interface(b_var->type)) {
assert(glsl_type_is_interface(a_var->type) &&
glsl_type_is_interface(b_var->type));
return nir_derefs_may_alias_bit;
}
/* If we can chase the deref all the way back to the variable and
* they're not the same variable and at least one is not declared
* coherent, we know they can't possibly alias.
/* Otherwise, distinct shared vars don't alias */
return nir_derefs_do_not_alias;
default:
/* For any other variable types, if we can chase them back to the
* variable, and the variables are different, they don't alias.
*/
if (a_var == b_var)
break;
return nir_derefs_do_not_alias;
}
} else {