Module: Mesa
Branch: master
Commit: 57165f2ef8ea743238ac1074fe80539a91da4835
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=57165f2ef8ea743238ac1074fe80539a91da4835
Author: Timothy Arceri <tarc...@itsqueeze.com>
Date: Thu May 25 12:29:20 2017 +1000
glsl: disable array splitting for AoA
While it produces functioning code the pass creates worse code
for arrays of arrays. See the comment added in this patch for more
detail.
V2: skip splitting of AoA of matrices too.
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
---
src/compiler/glsl/opt_array_splitting.cpp | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/src/compiler/glsl/opt_array_splitting.cpp
b/src/compiler/glsl/opt_array_splitting.cpp
index fb6d77bd94..d2e81665b7 100644
--- a/src/compiler/glsl/opt_array_splitting.cpp
+++ b/src/compiler/glsl/opt_array_splitting.cpp
@@ -140,6 +140,29 @@ ir_array_reference_visitor::get_variable_entry(ir_variable
*var)
if (var->type->is_unsized_array())
return NULL;
+ /* FIXME: arrays of arrays are not handled correctly by this pass so we
+ * skip it for now. While the pass will create functioning code it actually
+ * produces worse code.
+ *
+ * For example the array:
+ *
+ * int[3][2] a;
+ *
+ * ends up being split up into:
+ *
+ * int[3][2] a_0;
+ * int[3][2] a_1;
+ * int[3][2] a_2;
+ *
+ * And we end up referencing each of these new arrays for example:
+ *
+ * a[0][1] will be turned into a_0[0][1]
+ * a[1][0] will be turned into a_1[1][0]
+ * a[2][0] will be turned into a_2[2][0]
+ */
+ if (var->type->is_array() && var->type->fields.array->is_array())
+ return NULL;
+
foreach_in_list(variable_entry, entry, &this->variable_list) {
if (entry->var == var)
return entry;
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