[Mesa-stable] [Mesa-dev] [PATCH 02/10] intel/fs: Implement quad swizzles on ICL+.

Iago Toral itoral at igalia.com
Tue Jan 8 07:00:23 UTC 2019


On Mon, 2019-01-07 at 11:58 -0800, Francisco Jerez wrote:
> Iago Toral <itoral at igalia.com> writes:
> 
> > On Sat, 2018-12-29 at 12:38 -0800, Francisco Jerez wrote:
> > > Align16 is no longer a thing, so a new implementation is provided
> > > using Align1 instead.  Not all possible swizzles can be
> > > represented
> > > as
> > > a single Align1 region, but some fast paths are provided for
> > > frequently used swizzles that can be represented efficiently in
> > > Align1
> > > mode.
> > > 
> > > Fixes ~90 subgroup quad swap Vulkan CTS tests.
> > > 
> > > Cc: mesa-stable at lists.freedesktop.org
> > > ---
> > >  src/intel/compiler/brw_fs.cpp           | 25 +++++++-
> > >  src/intel/compiler/brw_fs.h             |  4 ++
> > >  src/intel/compiler/brw_fs_generator.cpp | 82
> > > ++++++++++++++++++++---
> > > --
> > >  3 files changed, 93 insertions(+), 18 deletions(-)
> > > 
> > > diff --git a/src/intel/compiler/brw_fs.cpp
> > > b/src/intel/compiler/brw_fs.cpp
> > > index 2f0f0151219..97544fdf465 100644
> > > --- a/src/intel/compiler/brw_fs.cpp
> > > +++ b/src/intel/compiler/brw_fs.cpp
> > > @@ -315,6 +315,20 @@ fs_inst::has_source_and_destination_hazard()
> > > const
> > >         * may stomp all over it.
> > >         */
> > >        return true;
> > > +   case SHADER_OPCODE_QUAD_SWIZZLE:
> > > +      switch (src[1].ud) {
> > 
> > Maybe it is worth adding a small comment here indicating that these
> > are
> > the cases where we implement the opcode as a single instruction and
> > refer to the generator for details?
> > 
> 
> Yeah, fixed up locally.
> 
> > > +      case BRW_SWIZZLE_XXXX:
> > > +      case BRW_SWIZZLE_YYYY:
> > > +      case BRW_SWIZZLE_ZZZZ:
> > > +      case BRW_SWIZZLE_WWWW:
> > > +      case BRW_SWIZZLE_XXZZ:
> > > +      case BRW_SWIZZLE_YYWW:
> > > +      case BRW_SWIZZLE_XYXY:
> > > +      case BRW_SWIZZLE_ZWZW:
> > > +         return false;
> > > +      default:
> > > +         return !is_uniform(src[0]);
> > 
> > Shouldn't this be:
> > 
> > return !is_uniform(src[0]) ||
> >        (devinfo->gen < 11 && type_sz(src.type) == 4);
> > 
> > Since in that case we also implement the opcode with a single
> > ALIGN16
> > instruction.
> > 
> 
> Not really.  Maybe you mean "!is_uniform(src[0]) &&
> (devinfo->gen >= 11 || type_sz(src.type) != 4)" instead? 

Ah yes, that's what I meant.

>  That would be
> somewhat more accurate than the expression in my patch, but
> unfortunately the devinfo pointer is not available here.  I wouldn't
> mind plumbing it through but patch is meant for mesa-stable, and it
> shouldn't affect correctness to be more strict than necessary
> regarding
> source/destination hazards.

Right, I didn't realize we didn't have devinfo available here. I guess
it is fine, the only drawback is that we might add a little bit more of
register pressure in (probably very few) cases in those gens, but that
is a very small issue I guess and it can be improved in a future patch
if we want.

> > > +      }
> > >     default:
> > >        /* The SIMD16 compressed instruction
> > >         *
> > > @@ -5579,9 +5593,14 @@ get_lowered_simd_width(const struct
> > > gen_device_info *devinfo,
> > >     case SHADER_OPCODE_URB_WRITE_SIMD8_MASKED_PER_SLOT:
> > >        return MIN2(8, inst->exec_size);
> > >  
> > > -   case SHADER_OPCODE_QUAD_SWIZZLE:
> > > -      return 8;
> > > -
> > > +   case SHADER_OPCODE_QUAD_SWIZZLE: {
> > > +      const unsigned swiz = inst->src[1].ud;
> > > +      return (is_uniform(inst->src[0]) ?
> > > +                 get_fpu_lowered_simd_width(devinfo, inst) :
> > > +              devinfo->gen < 11 && type_sz(inst->src[0].type) ==
> > > 4 ?
> > > 8 :
> > > +              swiz == BRW_SWIZZLE_XYXY || swiz ==
> > > BRW_SWIZZLE_ZWZW ?
> > > 4 :
> > > +              get_fpu_lowered_simd_width(devinfo, inst));
> > > +   }
> > >     case SHADER_OPCODE_MOV_INDIRECT: {
> > >        /* From IVB and HSW PRMs:
> > >         *
> > > diff --git a/src/intel/compiler/brw_fs.h
> > > b/src/intel/compiler/brw_fs.h
> > > index 53d9b6ce7bf..dc36ecc21ac 100644
> > > --- a/src/intel/compiler/brw_fs.h
> > > +++ b/src/intel/compiler/brw_fs.h
> > > @@ -480,6 +480,10 @@ private:
> > >                           struct brw_reg src,
> > >                           struct brw_reg idx);
> > >  
> > > +   void generate_quad_swizzle(const fs_inst *inst,
> > > +                              struct brw_reg dst, struct brw_reg
> > > src,
> > > +                              unsigned swiz);
> > > +
> > >     bool patch_discard_jumps_to_fb_writes();
> > >  
> > >     const struct brw_compiler *compiler;
> > > diff --git a/src/intel/compiler/brw_fs_generator.cpp
> > > b/src/intel/compiler/brw_fs_generator.cpp
> > > index 08dd83dded7..84627e83132 100644
> > > --- a/src/intel/compiler/brw_fs_generator.cpp
> > > +++ b/src/intel/compiler/brw_fs_generator.cpp
> > > @@ -582,6 +582,72 @@ fs_generator::generate_shuffle(fs_inst
> > > *inst,
> > >     }
> > >  }
> > >  
> > > +void
> > > +fs_generator::generate_quad_swizzle(const fs_inst *inst,
> > > +                                    struct brw_reg dst, struct
> > > brw_reg src,
> > > +                                    unsigned swiz)
> > > +{
> > > +   /* Requires a quad. */
> > > +   assert(inst->exec_size >= 4);
> > > +
> > > +   if (src.file == BRW_IMMEDIATE_VALUE ||
> > > +       has_scalar_region(src)) {
> > > +      /* The value is uniform across all channels */
> > > +      brw_MOV(p, dst, src);
> > > +
> > > +   } else if (devinfo->gen < 11 && type_sz(src.type) == 4) {
> > > +      /* This only works on 8-wide 32-bit values */
> > > +      assert(inst->exec_size == 8);
> > > +      assert(src.hstride == BRW_HORIZONTAL_STRIDE_1);
> > > +      assert(src.vstride == src.width + 1);
> > > +      brw_set_default_access_mode(p, BRW_ALIGN_16);
> > > +      struct brw_reg swiz_src = stride(src, 4, 4, 1);
> > > +      swiz_src.swizzle = swiz;
> > > +      brw_MOV(p, dst, swiz_src);
> > > +
> > 
> > Extra blank line.
> > 
> > > +   } else {
> > > +      assert(src.hstride == BRW_HORIZONTAL_STRIDE_1);
> > > +      assert(src.vstride == src.width + 1);
> > > +      const struct brw_reg src_0 = suboffset(src,
> > > BRW_GET_SWZ(swiz,
> > > 0));
> > > +
> > > +      switch (swiz) {
> > > +      case BRW_SWIZZLE_XXXX:
> > > +      case BRW_SWIZZLE_YYYY:
> > > +      case BRW_SWIZZLE_ZZZZ:
> > > +      case BRW_SWIZZLE_WWWW:
> > > +         brw_MOV(p, dst, stride(src_0, 4, 4, 0));
> > > +         break;
> > > +
> > > +      case BRW_SWIZZLE_XXZZ:
> > > +      case BRW_SWIZZLE_YYWW:
> > > +         brw_MOV(p, dst, stride(src_0, 2, 2, 0));
> > > +         break;
> > > +
> > > +      case BRW_SWIZZLE_XYXY:
> > > +      case BRW_SWIZZLE_ZWZW:
> > > +         assert(inst->exec_size == 4);
> > > +         brw_MOV(p, dst, stride(src_0, 0, 2, 1));
> > > +         break;
> > > +
> > > +      default:
> > > +         assert(inst->force_writemask_all);
> > > +         brw_set_default_exec_size(p, cvt(inst->exec_size / 4) -
> > > 1);
> > > +
> > > +         for (unsigned c = 0; c < 4; c++) {
> > > +            brw_inst *insn = brw_MOV(
> > > +               p, stride(suboffset(dst, c),
> > > +                         4 * inst->dst.stride, 1, 4 * inst-
> > > > dst.stride),
> > > 
> > > +               stride(suboffset(src, BRW_GET_SWZ(swiz, c)), 4,
> > > 1,
> > > 0));
> > > +
> > > +            brw_inst_set_no_dd_clear(devinfo, insn, c < 3);
> > > +            brw_inst_set_no_dd_check(devinfo, insn, c > 0);
> > > +         }
> > > +
> > > +         break;
> > > +      }
> > > +   }
> > > +}
> > > +
> > >  void
> > >  fs_generator::generate_urb_read(fs_inst *inst,
> > >                                  struct brw_reg dst,
> > > @@ -2303,23 +2369,9 @@ fs_generator::generate_code(const cfg_t
> > > *cfg,
> > > int dispatch_width)
> > >           break;
> > >  
> > >        case SHADER_OPCODE_QUAD_SWIZZLE:
> > > -         /* This only works on 8-wide 32-bit values */
> > > -         assert(inst->exec_size == 8);
> > > -         assert(type_sz(src[0].type) == 4);
> > > -         assert(inst->force_writemask_all);
> > >           assert(src[1].file == BRW_IMMEDIATE_VALUE);
> > >           assert(src[1].type == BRW_REGISTER_TYPE_UD);
> > > -
> > > -         if (src[0].file == BRW_IMMEDIATE_VALUE ||
> > > -             (src[0].vstride == 0 && src[0].hstride == 0)) {
> > > -            /* The value is uniform across all channels */
> > > -            brw_MOV(p, dst, src[0]);
> > > -         } else {
> > > -            brw_set_default_access_mode(p, BRW_ALIGN_16);
> > > -            struct brw_reg swiz_src = stride(src[0], 4, 4, 1);
> > > -            swiz_src.swizzle = inst->src[1].ud;
> > > -            brw_MOV(p, dst, swiz_src);
> > > -         }
> > > +         generate_quad_swizzle(inst, dst, src[0], src[1].ud);
> > >           break;
> > >  
> > >        case SHADER_OPCODE_CLUSTER_BROADCAST: {
> > 
> > _______________________________________________
> > mesa-stable mailing list
> > mesa-stable at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-stable



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