On 21/09/17 16:34, Ian Romanick wrote:
> 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.
Based on the cover-letter, I guess that are "regressions on shader-db
numbers, even on platforms that use NIR". Perhaps it is worth to mention
on the commit message?
>
> 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) {
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