From: "\"Ian Romanick\"" <i...@freedesktop.org>
From: Ian Romanick <ian.d.roman...@intel.com>
The optimization as done in opt_copy_propagation would have to be
removed in the next patch, and doing so would lead to some substantial
regressions.
Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
Cc: Jason Ekstrand <ja...@jlekstrand.net>
---
src/compiler/glsl/opt_copy_propagation.cpp | 19 +++++++------------
src/compiler/glsl/opt_dead_code_local.cpp | 11 +++++++++++
2 files changed, 18 insertions(+), 12 deletions(-)
diff --git a/src/compiler/glsl/opt_copy_propagation.cpp
b/src/compiler/glsl/opt_copy_propagation.cpp
index b72ae5a..b8ef0de0 100644
--- a/src/compiler/glsl/opt_copy_propagation.cpp
+++ b/src/compiler/glsl/opt_copy_propagation.cpp
@@ -348,18 +348,13 @@ ir_copy_propagation_visitor::add_copy(ir_assignment *ir)
ir_variable *lhs_var = ir->whole_variable_written();
ir_variable *rhs_var = ir->rhs->whole_variable_referenced();
- if ((lhs_var != NULL) && (rhs_var != NULL)) {
- if (lhs_var == rhs_var) {
- /* This is a dumb assignment, but we've conveniently noticed
- * it here. Removing it now would mess up the loop iteration
- * calling us. Just flag it to not execute, and someone else
- * will clean up the mess.
- */
- ir->condition = new(ralloc_parent(ir)) ir_constant(false);
- this->progress = true;
- } else if (lhs_var->data.mode != ir_var_shader_storage &&
- lhs_var->data.mode != ir_var_shader_shared &&
- lhs_var->data.precise == rhs_var->data.precise) {
+ /* Don't try to remove a dumb assignment of a variable to itself. Removing
+ * it now would mess up the loop iteration calling us.
+ */
+ if (lhs_var != NULL && rhs_var != NULL && lhs_var != rhs_var) {
+ if (lhs_var->data.mode != ir_var_shader_storage &&
+ lhs_var->data.mode != ir_var_shader_shared &&
+ lhs_var->data.precise == rhs_var->data.precise) {
assert(lhs_var);
assert(rhs_var);
_mesa_hash_table_insert(acp, lhs_var, rhs_var);
diff --git a/src/compiler/glsl/opt_dead_code_local.cpp
b/src/compiler/glsl/opt_dead_code_local.cpp
index a403879..3cbc441 100644
--- a/src/compiler/glsl/opt_dead_code_local.cpp
+++ b/src/compiler/glsl/opt_dead_code_local.cpp
@@ -173,6 +173,17 @@ process_assignment(void *lin_ctx, ir_assignment *ir,
exec_list *assignments)
bool progress = false;
kill_for_derefs_visitor v(assignments);
+ if (ir->condition == NULL) {
+ /* If this is an assignment of the form "foo = foo;", remove the whole
+ * instruction and be done with it.
+ */
+ const ir_variable *const lhs_var = ir->whole_variable_written();
+ if (lhs_var != NULL && lhs_var == ir->rhs->whole_variable_referenced()) {
+ ir->remove();
+ return true;
+ }
+ }
+
/* Kill assignment entries for things used to produce this assignment. */
ir->rhs->accept(&v);
if (ir->condition) {
--
2.9.5
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