Mesa (master): glsl: don't flatten if-blocks with dynamic array indices
Nicolai Hähnle
nh at kemper.freedesktop.org
Mon Nov 21 07:27:08 UTC 2016
Module: Mesa
Branch: master
Commit: 47db6b4600cfd3919c6120d392950d624b5a6ea7
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=47db6b4600cfd3919c6120d392950d624b5a6ea7
Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date: Thu Nov 17 22:24:07 2016 +0100
glsl: don't flatten if-blocks with dynamic array indices
This fixes the regression of radeonsi in
glsl-1.10/execution/variable-indexing/vs-output-array-vec3-index-wr
caused by commit 74e39de9324d2d2333cda6adca50ae2a3fc36de2.
Acked-by: Edward O'Callaghan <funfunctor at folklore1984.net>
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
---
src/compiler/glsl/lower_if_to_cond_assign.cpp | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/src/compiler/glsl/lower_if_to_cond_assign.cpp b/src/compiler/glsl/lower_if_to_cond_assign.cpp
index ae048be..37f1ec8 100644
--- a/src/compiler/glsl/lower_if_to_cond_assign.cpp
+++ b/src/compiler/glsl/lower_if_to_cond_assign.cpp
@@ -86,6 +86,7 @@ public:
bool found_unsupported_op;
bool found_expensive_op;
+ bool found_dynamic_arrayref;
bool is_then;
bool progress;
gl_shader_stage stage;
@@ -148,8 +149,13 @@ check_ir_node(ir_instruction *ir, void *data)
v->found_expensive_op = true;
break;
+ case ir_type_dereference_array: {
+ ir_dereference_array *deref = ir->as_dereference_array();
+
+ if (deref->array_index->ir_type != ir_type_constant)
+ v->found_dynamic_arrayref = true;
+ } /* fall-through */
case ir_type_expression:
- case ir_type_dereference_array:
case ir_type_dereference_record:
if (v->is_then)
v->then_cost++;
@@ -229,6 +235,7 @@ ir_if_to_cond_assign_visitor::visit_leave(ir_if *ir)
this->found_unsupported_op = false;
this->found_expensive_op = false;
+ this->found_dynamic_arrayref = false;
this->then_cost = 0;
this->else_cost = 0;
@@ -248,9 +255,17 @@ ir_if_to_cond_assign_visitor::visit_leave(ir_if *ir)
if (this->found_unsupported_op)
return visit_continue; /* can't handle inner unsupported opcodes */
- /* Skip if the branch cost is high enough or if there's an expensive op. */
+ /* Skip if the branch cost is high enough or if there's an expensive op.
+ *
+ * Also skip if non-constant array indices were encountered, since those
+ * can be out-of-bounds for a not-taken branch, and so generating an
+ * assignment would be incorrect. In the case of must_lower, it's up to the
+ * backend to deal with any potential fall-out (perhaps by translating the
+ * assignments to hardware-predicated moves).
+ */
if (!must_lower &&
(this->found_expensive_op ||
+ this->found_dynamic_arrayref ||
MAX2(this->then_cost, this->else_cost) >= this->min_branch_cost))
return visit_continue;
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