[Mesa-dev] [PATCH 1/2] i965/fs: Perform CSE on MAD instructions with final arguments switched.

[Kenneth Graunke]

On Wednesday, October 29, 2014 02:09:55 PM Matt Turner wrote:
> Multiplication is commutative.
> 
> instructions in affected programs:     48314 -> 47954 (-0.75%)
> ---
>  src/mesa/drivers/dri/i965/brw_fs_cse.cpp | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp 
b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
> index 8012001..5fdbf46 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
> @@ -128,7 +128,11 @@ operands_match(fs_inst *a, fs_inst *b)
>     fs_reg *xs = a->src;
>     fs_reg *ys = b->src;
>  
> -   if (!is_expression_commutative(a->opcode)) {
> +   if (a->opcode == BRW_OPCODE_MAD) {
> +      return xs[0].equals(ys[0]) &&
> +             ((xs[1].equals(ys[1]) && xs[2].equals(ys[2])) ||
> +              (xs[2].equals(ys[1]) && xs[1].equals(ys[2])));
> +   } else if (!is_expression_commutative(a->opcode)) {
>        bool match = true;
>        for (int i = 0; i < a->sources; i++) {
>           if (!xs[i].equals(ys[i])) {
> 

Series is:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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