[Mesa-dev] [PATCH 1/6] r600g: Add no_merge_inst_groups flag

[Tom Stellard]

On Thu, Apr 26, 2012 at 08:46:52AM -0400, Tom Stellard wrote:
> Setting this flag will skip the merge_inst_groups() function.
> ---
>  src/gallium/drivers/r600/r600_asm.c |    3 ++-
>  src/gallium/drivers/r600/r600_asm.h |   10 ++++++++++
>  2 files changed, 12 insertions(+), 1 deletions(-)
> 
> diff --git a/src/gallium/drivers/r600/r600_asm.c b/src/gallium/drivers/r600/r600_asm.c
> index 0ecca36..5f83879 100644
> --- a/src/gallium/drivers/r600/r600_asm.c
> +++ b/src/gallium/drivers/r600/r600_asm.c
> @@ -1034,6 +1034,7 @@ static int merge_inst_groups(struct r600_bytecode *bc, struct r600_bytecode_alu
>  	int have_mova = 0, have_rel = 0;
>  	int max_slots = bc->chip_class == CAYMAN ? 4 : 5;
>  
> +	assert(!bc->no_merge_inst_groups);
>  	r = assign_alu_units(bc, alu_prev, prev);
>  	if (r)
>  		return r;
> @@ -1481,7 +1482,7 @@ int r600_bytecode_add_alu_type(struct r600_bytecode *bc, const struct r600_bytec
>  		if (r)
>  			return r;
>  
> -		if (bc->cf_last->prev_bs_head) {
> +		if (!bc->no_merge_inst_groups && bc->cf_last->prev_bs_head) {
>  			r = merge_inst_groups(bc, slots, bc->cf_last->prev_bs_head);
>  			if (r)
>  				return r;
> diff --git a/src/gallium/drivers/r600/r600_asm.h b/src/gallium/drivers/r600/r600_asm.h
> index 5790ead..86d44d3 100644
> --- a/src/gallium/drivers/r600/r600_asm.h
> +++ b/src/gallium/drivers/r600/r600_asm.h
> @@ -205,6 +205,16 @@ struct r600_bytecode {
>  	unsigned	ar_reg;
>  	unsigned        ar_handling;
>  	unsigned        r6xx_nop_after_rel_dst;
> +
> +	/* Setting this bit will prevent the r600 assembler from trying to
> +	 * merge instruction groups.  This is necessary for compute shaders,
> +	 * because the CF_ALLOC_EXPORT_WORD0_RAT instructions expects the index
> +	 * values to be in the X, Y, and Z channels depending on the
> +	 * dimension of the surface.  The merge_inst_groups function will move
> +	 * these values around to the wrong channels and the RAT read or write
> +	 * will fail.
> +	 */

vadimg has pointed out on IRC that this comment is wrong, and the
merge_inst_groups function won't rewrite the destination channels.

I think this patch might still be useful, so I'll just drop this comment
from the final version.

-Tom

> +	unsigned			no_merge_inst_groups;
>  };
>  
>  /* eg_asm.c */
> -- 
> 1.7.7.6
> 
>