On Fri, Nov 04, 2016 at 05:59:29PM -0700, Jason Ekstrand wrote:
> On Nov 4, 2016 2:30 AM, "Pohjolainen, Topi"
> <[1]topi.pohjolai...@gmail.com> wrote:
> >
> > On Fri, Nov 04, 2016 at 11:17:13AM +0200, Pohjolainen, Topi wrote:
> > > On Fri, Oct 28, 2016 at 02:17:12AM -0700, Jason Ekstrand wrote:
> > > > Previously, blorp copy operations were CCS-unaware so you had to
> perform
> > > > resolves on the source and destination before performing the
> copy. This
> > > > commit makes blorp_copy capable of handling CCS-compressed images
> without
> > > > any resolves.
> > > >
> > > > Signed-off-by: Jason Ekstrand <[2]ja...@jlekstrand.net>
> > > > ---
> > > > src/intel/blorp/blorp_blit.c | 173
> ++++++++++++++++++++++++++++++++++++++++++-
> > > > src/intel/blorp/blorp_priv.h | 6 ++
> > > > 2 files changed, 177 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/src/intel/blorp/blorp_blit.c
> b/src/intel/blorp/blorp_blit.c
> > > > index 07bb181..598b7c9 100644
> > > > --- a/src/intel/blorp/blorp_blit.c
> > > > +++ b/src/intel/blorp/blorp_blit.c
> > > > @@ -851,6 +851,66 @@ blorp_nir_manual_blend_bilinear(nir_builder
> *b, nir_ssa_def *pos,
> > > > frac_y);
> > > > }
> > > >
> > > > +/** Perform a color bit-cast operation
> > > > + *
> > > > + * For copy operations involving CCS, we may need to use
> different formats for
> > > > + * the source and destination surfaces. The two formats must
> both be UINT
> > > > + * formats and must have the same size but may have different
> bit layouts.
> > > > + * For instance, we may be copying from R8G8B8A8_UINT to
> R32_UINT or R32_UINT
> > > > + * to R16G16_UINT. This function generates code to shuffle bits
> around to get
> > > > + * us from one to the other.
> > > > + */
> > > > +static nir_ssa_def *
> > > > +bit_cast_color(struct nir_builder *b, nir_ssa_def *color,
> > > > + const struct brw_blorp_blit_prog_key *key)
> > > > +{
> > > > + assert(key->texture_data_type == nir_type_uint);
> > > > +
> > > > + if (key->dst_bpc > key->src_bpc) {
> > > > + nir_ssa_def *u = nir_ssa_undef(b, 1, 32);
> > > > + nir_ssa_def *dst_chan[2] = { u, u };
> > > > + unsigned shift = 0;
> > > > + unsigned dst_idx = 0;
> > > > + for (unsigned i = 0; i < 4; i++) {
> > > > + nir_ssa_def *shifted = nir_ishl(b, nir_channel(b,
> color, i),
> > > > + nir_imm_int(b,
> shift));
> > > > + if (shift == 0) {
> > > > + dst_chan[dst_idx] = shifted;
> > > > + } else {
> > > > + dst_chan[dst_idx] = nir_ior(b, dst_chan[dst_idx],
> shifted);
> > > > + }
> > > > +
> > > > + shift += key->src_bpc;
> > > > + if (shift >= key->dst_bpc) {
> > > > + dst_idx++;
> > > > + shift = 0;
> > > > + }
> > > > + }
> > >
> > > This iterates unconditionally over 4 source components regardless
> how many
> > > there are in source, right? Lets assume we have dst == R32_UINT and
> > > src == R16G16_UINT, don't we get the following where iterations
> with i = 2
> > > and i = 3 try to access non-existing z and w components:
> > >
> > > i = 0:
> > > nir_ssa_def *shifted = nir_ishl(b, nir_channel(b,
> color, 0),
> > > nir_imm_int(b, 0));
> > > dst_chan[0] = shifted;
> > >
> > > i = 1:
> > > nir_ssa_def *shifted = nir_ishl(b, nir_channel(b,
> color, 1),
> > > nir_imm_int(b, 16));
> > > dst_chan[0] = nir_ior(b, dst_chan[0], shifted);
> > >
> > > i = 2:
> > > nir_ssa_def *shifted = nir_ishl(b, nir_channel(b,
> color, 2),
> > > nir_imm_int(b, 0));
> > > dst_chan[1] = shifted;
> > >
> > > i = 3:
> > > nir_ssa_def *shifted = nir_ishl(b, nir_channel(b,
> color, 3),
> > > nir_imm_int(b, 16));
> > > dst_chan[1] = nir_ior(b, dst_chan[1], shifted);
> >
> > If this is intentional and the idea is to rely on optimization passes
> to
> > remove unnecessary writes to "dst_chan[1]" then a comment would be
> nice.
>
> It is intentional but instead of relying on any compiler magic, we're
> just relying on the fact that the texturing instruction always returns
> a vec4 and the render target write always takes a vec4. I could have
> included the number of components in the key and used that to not
> generate pointless conversion code in a few places but that would have
> ended up making it more complicated and we would end up generating more
> distinct shader programs for only marginal benefit.
Ah, okay, I didn't think that. Thanks for fixing this (I can drop one of
my patches):
Reviewed-by: Topi Pohjolainen <topi.pohjolai...@intel.com>
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
