[Mesa-dev] [PATCH 1/3] i965/fs: Detect multi-register MOVs correctly in register_coalesce.

[Jason Ekstrand]

On Jul 28, 2015 2:43 AM, "Francisco Jerez" <currojerez at riseup.net> wrote:
>
> register_coalesce() was considering the exec_size of the MOV
> instruction alone to decide whether the register at offset+1 of the
> source VGRF was being copied to inst->dst.reg_offset+1 of the
> destination VGRF, which is only a valid assumption if the move has a
> 32-bit execution type.  Use regs_read() instead to find out the number
> of registers copied by the instruction.
> ---
>  src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
> index a253c81..4544122 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
> @@ -195,7 +195,7 @@ fs_visitor::register_coalesce()
>              continue;
>           }
>           reg_to_offset[offset] = inst->dst.reg_offset;
> -         if (inst->exec_size == 16)
> +         if (inst->regs_read(0) > 1)
>              reg_to_offset[offset + 1] = inst->dst.reg_offset + 1;
>           mov[offset] = inst;
>           channels_remaining -= inst->regs_written;

And then we use regs_written directly below...

Off you want it to be more consistent, we could use regs_written for both.
Either wary,

Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com>

> --
> 2.4.6
>
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