[Mesa-stable] [PATCH] intel/compiler: do not copy-propagate strided regions to ddx/ddy arguments

[Iago Toral]

Yes,it was a mistake, since I had sent it manually to mesa-stable I
understood it was not necessary to add the CC again when I pushed it to
master.

Iago

On Mon, 2018-12-17 at 11:42 +0100, Juan A. Suarez Romero wrote:
> On Tue, 2018-12-11 at 12:22 +0100, Iago Toral Quiroga wrote:
> > The implementation of these opcodes in the generator assumes that
> > their
> > arguments are packed, and it generates register regions based on
> > that
> > assumption.
> > 
> > Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
> 
> 
> This patch landed in master without CCed to stable.
> 
> I understand this was done explicitly, so I'll keep this out of 18.2
> stable
> queue.
> 
> If this was a mistake, and you think this patch should be in 18.2
> stable, let me
> know.
> 
> Thanks.
> 
> 	J.A.
> 
> > ---
> > Although this patch hasn't landed in master yet (it is part of a
> > larger series
> > that is still in review), Jason suggested to backport it to stable.
> > I guess it
> > might be a good idea to land it early in master too if we are doing
> > this
> > though.
> > 
> >  .../compiler/brw_fs_copy_propagation.cpp      | 21
> > +++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/src/intel/compiler/brw_fs_copy_propagation.cpp
> > b/src/intel/compiler/brw_fs_copy_propagation.cpp
> > index ab34b63748..a8ec1c3463 100644
> > --- a/src/intel/compiler/brw_fs_copy_propagation.cpp
> > +++ b/src/intel/compiler/brw_fs_copy_propagation.cpp
> > @@ -361,6 +361,20 @@ can_take_stride(fs_inst *inst, unsigned arg,
> > unsigned stride,
> >     return true;
> >  }
> >  
> > +static bool
> > +instruction_requires_packed_data(fs_inst *inst)
> > +{
> > +   switch (inst->opcode) {
> > +   case FS_OPCODE_DDX_FINE:
> > +   case FS_OPCODE_DDX_COARSE:
> > +   case FS_OPCODE_DDY_FINE:
> > +   case FS_OPCODE_DDY_COARSE:
> > +      return true;
> > +   default:
> > +      return false;
> > +   }
> > +}
> > +
> >  bool
> >  fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry
> > *entry)
> >  {
> > @@ -407,6 +421,13 @@ fs_visitor::try_copy_propagate(fs_inst *inst,
> > int arg, acp_entry *entry)
> >         inst->opcode == SHADER_OPCODE_GEN4_SCRATCH_WRITE)
> >        return false;
> >  
> > +   /* Some instructions implemented in the generator backend, such
> > as
> > +    * derivatives, assume that their operands are packed so we
> > can't
> > +    * generally propagate strided regions to them.
> > +    */
> > +   if (instruction_requires_packed_data(inst) && entry->src.stride 
> > > 1)
> > +      return false;
> > +
> >     /* Bail if the result of composing both strides would exceed
> > the
> >      * hardware limit.
> >      */
> 
>