[Mesa-dev] [PATCH 05/14] i965/compaction: Make src_offset local to the for loop.

[Ian Romanick]

On 08/28/2014 08:10 PM, Matt Turner wrote:
> ---
>  src/mesa/drivers/dri/i965/brw_eu_compact.c | 17 +++++++----------
>  1 file changed, 7 insertions(+), 10 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_eu_compact.c b/src/mesa/drivers/dri/i965/brw_eu_compact.c
> index 5617947..dd32175 100644
> --- a/src/mesa/drivers/dri/i965/brw_eu_compact.c
> +++ b/src/mesa/drivers/dri/i965/brw_eu_compact.c
> @@ -737,6 +737,8 @@ brw_try_compact_instruction(struct brw_context *brw, brw_compact_inst *dst,
>  {
>     brw_compact_inst temp;
>  
> +   assert(brw_inst_cmpt_control(brw, src) == 0);
> +
>     if (brw_inst_opcode(brw, src) == BRW_OPCODE_IF ||
>         brw_inst_opcode(brw, src) == BRW_OPCODE_ELSE ||
>         brw_inst_opcode(brw, src) == BRW_OPCODE_ENDIF ||
> @@ -1105,10 +1107,10 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
>     if (brw->gen < 6)
>        return;
>  
> -   int src_offset;
>     int offset = 0;
>     int compacted_count = 0;
> -   for (src_offset = 0; src_offset < p->next_insn_offset - start_offset;) {
> +   for (int src_offset = 0; src_offset < p->next_insn_offset - start_offset;
> +        src_offset += sizeof(brw_inst)) {
>        brw_inst *src = store + src_offset;
>        void *dst = store + offset;
>  
> @@ -1117,8 +1119,7 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
>  
>        brw_inst saved = *src;
>  
> -      if (!brw_inst_cmpt_control(brw, src) &&
> -          brw_try_compact_instruction(brw, dst, src)) {
> +      if (brw_try_compact_instruction(brw, dst, src)) {
>           compacted_count++;
>  
>           if (INTEL_DEBUG) {
> @@ -1130,10 +1131,7 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
>           }
>  
>           offset += 8;
> -         src_offset += 16;
>        } else {
> -         int size = brw_inst_cmpt_control(brw, src) ? 8 : 16;
> -
>           /* It appears that the end of thread SEND instruction needs to be
>            * aligned, or the GPU hangs.
>            */
> @@ -1154,10 +1152,9 @@ brw_compact_instructions(struct brw_compile *p, int start_offset,
>            * place.
>            */
>           if (offset != src_offset) {
> -            memmove(dst, src, size);
> +            memmove(dst, src, sizeof(brw_inst));
>           }
> -         offset += size;
> -         src_offset += size;
> +         offset += sizeof(brw_inst);

Sometimes this would increment src_offset by 8 and sometimes by 16.  Now
src_offset is always incremented by sizeof(brw_inst).  I'm not grokking
it enough to know if this is the same issue that Ken and Jason mentioned.

>        }
>     }
>  
>