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

Francisco Jerez currojerez at riseup.net
Mon Jan 7 19:58:07 UTC 2019


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?  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.

>> +      }
>>     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: {
>
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