[Mesa-dev] [PATCH 5/5] i965/fs: don't make unused payload registers interfere

[Jordan Justen]

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

On 2015-07-01 11:51:39, Connor Abbott wrote:
> From: Connor Abbott <cwabbott0 at gmail.com>
> 
> Before, we were setting payload_last_use_ip for unused payload
> registers to 0, which made them interfere with whatever the first
> instruction wrote to due to the workaround for SIMD16 uniform arguments.
> Just use -1 to mean "unused" instead, and then skip setting any
> interferences for unused payload registers.
> 
> instructions in affected programs:     0 -> 0
> helped:                                0
> HURT:                                  0
> GAINED:                                1
> LOST:                                  0
> 
> Signed-off-by: Connor Abbott <connor.w.abbott at intel.com>
> ---
>  src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
> index 1ee19e4..f25f2ec 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
> @@ -341,7 +341,9 @@ fs_visitor::setup_payload_interference(struct ra_graph *g,
>     int loop_end_ip = 0;
>  
>     int payload_last_use_ip[payload_node_count];
> -   memset(payload_last_use_ip, 0, sizeof(payload_last_use_ip));
> +   for (int i = 0; i < payload_node_count; i++)
> +      payload_last_use_ip[i] = -1;
> +
>     int ip = 0;
>     foreach_block_and_inst(block, fs_inst, inst, cfg) {
>        switch (inst->opcode) {
> @@ -411,6 +413,9 @@ fs_visitor::setup_payload_interference(struct ra_graph *g,
>     }
>  
>     for (int i = 0; i < payload_node_count; i++) {
> +      if (payload_last_use_ip[i] == -1)
> +         continue;
> +
>        /* Mark the payload node as interfering with any virtual grf that is
>         * live between the start of the program and our last use of the payload
>         * node.
> -- 
> 2.4.3
> 
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