[Mesa-dev] [PATCH 1/2] mesa: remove redundant modulus operation

[Ian Romanick]

On 05/23/2017 05:01 AM, Timothy Arceri wrote:
> The if check above means we can only get here if size is less than 4.
> ---
>  src/mesa/program/prog_parameter.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/src/mesa/program/prog_parameter.c b/src/mesa/program/prog_parameter.c
> index 44e680c..40bc47d 100644
> --- a/src/mesa/program/prog_parameter.c
> +++ b/src/mesa/program/prog_parameter.c
> @@ -260,23 +260,22 @@ _mesa_add_parameter(struct gl_program_parameter_list *paramList,
>        struct gl_program_parameter *p = paramList->Parameters + oldNum + i;
>        p->Name = strdup(name ? name : "");
>        p->Type = type;
>        p->Size = size;
>        p->DataType = datatype;
>        if (values) {
>           if (size >= 4) {
>              COPY_4V(paramList->ParameterValues[oldNum + i], values);
>           } else {
>              /* copy 1, 2 or 3 values */
> -            GLuint remaining = size % 4;
> -            assert(remaining < 4);
> -            for (j = 0; j < remaining; j++) {
> +            assert(size < 4);
> +            for (j = 0; j < size; j++) {
>                 paramList->ParameterValues[oldNum + i][j].f = values[j].f;
>              }
>              /* fill in remaining positions with zeros */
>              for (; j < 4; j++) {
>                 paramList->ParameterValues[oldNum + i][j].f = 0.0f;
>              }

It might be interesting to see if just setting all four values to 0.0
before the copy produces better code.  There are a bunch of different
micro optimizations possible depending on what GCC does.

Either way, this patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

>           }
>           values += 4;
>        } else {
>           /* silence valgrind */
>