[Mesa-dev] [PATCH 12/59] i965: add brw_imm_df

[Francisco Jerez]

Samuel Iglesias Gonsálvez <siglesias at igalia.com> writes:

> From: Connor Abbott <connor.w.abbott at intel.com>
>
> v2 (Iago)
>   - Fixup accessibility in backend_reg
>
> Signed-off-by: Iago Toral Quiroga <itoral at igalia.com>

I've just noticed (while running valgrind) that this patch causes
serious breakage in the back-end.  The reason is that the extra bits
required to make room for the df field of the union don't get
initialized in all codepaths, so backend_reg comparisons done using
memcmp() can basically return random results now.  Can you please look
into this?  Some ways to fix it would be to make sure we zero-initialize
the whole brw_reg in all cases (or at least the union padding), or stop
using memcmp() to compare registers -- I guess the latter might be
somewhat less intrusive and increase the likelihood that we can get this
sorted out timely.

> ---
>  src/mesa/drivers/dri/i965/brw_reg.h    | 9 +++++++++
>  src/mesa/drivers/dri/i965/brw_shader.h | 1 +
>  2 files changed, 10 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_reg.h b/src/mesa/drivers/dri/i965/brw_reg.h
> index b84c709..6d51623 100644
> --- a/src/mesa/drivers/dri/i965/brw_reg.h
> +++ b/src/mesa/drivers/dri/i965/brw_reg.h
> @@ -254,6 +254,7 @@ struct brw_reg {
>           unsigned pad1:1;
>        };
>  
> +      double df;
>        float f;
>        int   d;
>        unsigned ud;
> @@ -544,6 +545,14 @@ brw_imm_reg(enum brw_reg_type type)
>  
>  /** Construct float immediate register */
>  static inline struct brw_reg
> +brw_imm_df(double df)
> +{
> +   struct brw_reg imm = brw_imm_reg(BRW_REGISTER_TYPE_DF);
> +   imm.df = df;
> +   return imm;
> +}
> +
> +static inline struct brw_reg
>  brw_imm_f(float f)
>  {
>     struct brw_reg imm = brw_imm_reg(BRW_REGISTER_TYPE_F);
> diff --git a/src/mesa/drivers/dri/i965/brw_shader.h b/src/mesa/drivers/dri/i965/brw_shader.h
> index fc228f6..f6f6167 100644
> --- a/src/mesa/drivers/dri/i965/brw_shader.h
> +++ b/src/mesa/drivers/dri/i965/brw_shader.h
> @@ -90,6 +90,7 @@ struct backend_reg : private brw_reg
>     using brw_reg::width;
>     using brw_reg::hstride;
>  
> +   using brw_reg::df;
>     using brw_reg::f;
>     using brw_reg::d;
>     using brw_reg::ud;
> -- 
> 2.5.0
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 212 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20160510/82f33439/attachment.sig>