Patch provides new compiler option for backend to force unroll loops
that have non-constant expression indexing on sampler arrays.
This makes sure that we can never end up with a shader that uses loop
induction variable as sampler array index but does not unroll because
of having too much instructions. This would not work without dynamic
indexing support.
Signed-off-by: Tapani Pälli <tapani.pa...@intel.com>
---
src/glsl/loop_unroll.cpp | 10 ++++++++++
src/mesa/main/mtypes.h | 6 ++++++
2 files changed, 16 insertions(+)
diff --git a/src/glsl/loop_unroll.cpp b/src/glsl/loop_unroll.cpp
index 635e1dd..b9de51d 100644
--- a/src/glsl/loop_unroll.cpp
+++ b/src/glsl/loop_unroll.cpp
@@ -100,6 +100,16 @@ public:
virtual ir_visitor_status visit_enter(ir_dereference_array *ir)
{
+ /* Force unroll in case of dynamic indexing with sampler arrays. */
+ if (options->UnrollSamplerArrayDynamicIndexing) {
+ if ((ir->array->type->is_array() &&
+ ir->array->type->contains_sampler()) &&
+ !ir->array_index->constant_expression_value()) {
+ unsupported_variable_indexing = true;
+ return visit_continue;
+ }
+ }
+
/* Check for arrays variably-indexed by a loop induction variable.
* Unrolling the loop may convert that access into constant-indexing.
*
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 1598e2c..61d1dfb 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2896,6 +2896,12 @@ struct gl_shader_compiler_options
*/
GLboolean OptimizeForAOS;
+ /**
+ * Unroll any loops with dynamic indexing to sampler array. This can be used
+ * to force loop unroll from the backend for GLSL <= 1.20 and GLSL ES 1.00.
+ */
+ GLboolean UnrollSamplerArrayDynamicIndexing;
+
const struct nir_shader_compiler_options *NirOptions;
};
--
2.1.0
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