[Mesa-dev] [PATCH] glsl: don't flatten if-blocks with dynamic array indices
Nicolai Hähnle
nhaehnle at gmail.com
Thu Nov 17 21:59:26 UTC 2016
From: Nicolai Hähnle <nicolai.haehnle at amd.com>
This fixes the regression of radeonsi in
glsl-1.10/execution/variable-indexing/vs-output-array-vec3-index-wr
caused by commit 74e39de9324d2d2333cda6adca50ae2a3fc36de2.
---
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
@@ -79,20 +79,21 @@ public:
~ir_if_to_cond_assign_visitor()
{
_mesa_set_destroy(this->condition_variables, NULL);
}
ir_visitor_status visit_enter(ir_if *);
ir_visitor_status visit_leave(ir_if *);
bool found_unsupported_op;
bool found_expensive_op;
+ bool found_dynamic_arrayref;
bool is_then;
bool progress;
gl_shader_stage stage;
unsigned then_cost;
unsigned else_cost;
unsigned min_branch_cost;
unsigned max_depth;
unsigned depth;
struct set *condition_variables;
@@ -141,22 +142,27 @@ check_ir_node(ir_instruction *ir, void *data)
var->data.mode == ir_var_shader_out)
v->found_unsupported_op = true;
break;
}
/* SSBO, images, atomic counters are handled by ir_type_call */
case ir_type_texture:
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++;
else
v->else_cost++;
break;
default:
break;
}
@@ -222,42 +228,51 @@ ir_visitor_status
ir_if_to_cond_assign_visitor::visit_leave(ir_if *ir)
{
bool must_lower = this->depth-- > this->max_depth;
/* Only flatten when beyond the GPU's maximum supported nesting depth. */
if (!must_lower && this->min_branch_cost == 0)
return visit_continue;
this->found_unsupported_op = false;
this->found_expensive_op = false;
+ this->found_dynamic_arrayref = false;
this->then_cost = 0;
this->else_cost = 0;
ir_assignment *assign;
/* Check that both blocks don't contain anything we can't support. */
this->is_then = true;
foreach_in_list(ir_instruction, then_ir, &ir->then_instructions) {
visit_tree(then_ir, check_ir_node, this);
}
this->is_then = false;
foreach_in_list(ir_instruction, else_ir, &ir->else_instructions) {
visit_tree(else_ir, check_ir_node, this);
}
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;
void *mem_ctx = ralloc_parent(ir);
/* Store the condition to a variable. Move all of the instructions from
* the then-clause of the if-statement. Use the condition variable as a
* condition for all assignments.
*/
ir_variable *const then_var =
--
2.7.4
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