I had thought about doing something similar once upon a time, but I
never got around to it. I'm glad you got some good performance data.
With the couple typos fixed, this patch is
Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
On 08/19/2015 09:37 PM, Timothy Arceri wrote:
> The constant folding pass can take a long time to complete
> so rather than running throught the entire pass each time
through
> a new constant is propagated (and vice versa) interleave them.
>
> This change helps ES31-CTS.arrays_of_arrays.InteractionFunctionCalls1
> go from around 2 min -> 23 sec.
> ---
> src/glsl/opt_constant_propagation.cpp | 46 +++++++++++++++++++++++++++++++++--
> 1 file changed, 44 insertions(+), 2 deletions(-)
>
> diff --git a/src/glsl/opt_constant_propagation.cpp b/src/glsl/opt_constant_propagation.cpp
> index 10be8e8..ebe30d9 100644
> --- a/src/glsl/opt_constant_propagation.cpp
> +++ b/src/glsl/opt_constant_propagation.cpp
> @@ -110,6 +110,8 @@ public:
> virtual ir_visitor_status visit_enter(class ir_if *);
>
> void add_constant(ir_assignment *ir);
> + void constant_folding(ir_rvalue **rvalue);
> + void constant_propagation(ir_rvalue **rvalue);
> void kill(ir_variable *ir, unsigned write_mask);
> void handle_if_block(exec_list *instructions);
> void handle_rvalue(ir_rvalue **rvalue);
> @@ -132,8 +134,39 @@ public:
>
>
> void
> -ir_constant_propagation_visitor::handle_rvalue(ir_rvalue **rvalue)
> -{
> +ir_constant_propagation_visitor::constant_folding(ir_rvalue **rvalue) {
> +
> + if (*rvalue == NULL || (*rvalue)->ir_type == ir_type_constant)
> + return;
> +
> + /* Note that we do rvalue visitoring on leaving. So if an
Note that we visit rvalues one leaving.
> + * expression has a non-constant operand, no need to go looking
> + * down it to find if it's constant. This cuts the time of this
> + * pass down drastically.
> + */
> + ir_expression *expr = (*rvalue)->as_expression();
> + if (expr) {
> + for (unsigned int i = 0; i < expr->get_num_operands(); i++) {
> + if (!expr->operands[i]->as_constant())
> + return;
> + }
> + }
> +
> + /* Ditto for swizzles. */
> + ir_swizzle *swiz = (*rvalue)->as_swizzle();
> + if (swiz && !swiz->val->as_constant())
> + return;
> +
> + ir_constant *constant = (*rvalue)->constant_expression_value();
> + if (constant) {
> + *rvalue = constant;
> + this->progress = true;
> + }
> +}
> +
> +void
> +ir_constant_propagation_visitor::constant_propagation(ir_rvalue **rvalue) {
> +
> if (this->in_assignee || !*rvalue)
> return;
>
> @@ -216,6 +249,13 @@ ir_constant_propagation_visitor::handle_rvalue(ir_rvalue **rvalue)
> this->progress = true;
> }
>
> +void
> +ir_constant_propagation_visitor::handle_rvalue(ir_rvalue **rvalue)
> +{
> + constant_propagation(rvalue);
> + constant_folding(rvalue);
> +}
> +
> ir_visitor_status
> ir_constant_propagation_visitor::visit_enter(ir_function_signature *ir)
> {
> @@ -243,6 +283,8 @@ ir_constant_propagation_visitor::visit_enter(ir_function_signature *ir)
> ir_visitor_status
> ir_constant_propagation_visitor::visit_leave(ir_assignment *ir)
> {
> + constant_folding(&ir->rhs);
> +
> if (this->in_assignee)
> return visit_continue;
>
>