[Mesa-dev] [PATCH 2/7] i965/fs: Use a stride of 1 and byte offsets for UBOs

[Matt Turner]

On Mon, Nov 23, 2015 at 6:11 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> ---
>  src/mesa/drivers/dri/i965/brw_fs.cpp             | 16 ++++++++--------
>  src/mesa/drivers/dri/i965/brw_fs_nir.cpp         | 11 ++++-------
>  src/mesa/drivers/dri/i965/brw_wm_surface_state.c |  2 +-
>  3 files changed, 13 insertions(+), 16 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> index 777cee5..9e2b1fa2 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> @@ -187,7 +187,7 @@ fs_visitor::VARYING_PULL_CONSTANT_LOAD(const fs_builder &bld,
>      * the redundant ones.
>      */
>     fs_reg vec4_offset = vgrf(glsl_type::int_type);
> -   bld.ADD(vec4_offset, varying_offset, brw_imm_ud(const_offset & ~3));
> +   bld.ADD(vec4_offset, varying_offset, brw_imm_ud(const_offset & ~0xf));
>
>     int scale = 1;
>     if (devinfo->gen == 4 && bld.dispatch_width() == 8) {
> @@ -219,7 +219,7 @@ fs_visitor::VARYING_PULL_CONSTANT_LOAD(const fs_builder &bld,
>           inst->mlen = 1 + bld.dispatch_width() / 8;
>     }
>
> -   bld.MOV(dst, offset(vec4_result, bld, (const_offset & 3) * scale));
> +   bld.MOV(dst, offset(vec4_result, bld, ((const_offset & 0xf) / 4) * scale));
>  }
>
>  /**
> @@ -1999,10 +1999,12 @@ fs_visitor::demote_pull_constants()
>
>           /* Generate a pull load into dst. */
>           if (inst->src[i].reladdr) {
> +            fs_reg indirect = ibld.vgrf(BRW_REGISTER_TYPE_D);
> +            ibld.MUL(indirect, *inst->src[i].reladdr, brw_imm_d(4));
>              VARYING_PULL_CONSTANT_LOAD(ibld, dst,
>                                         brw_imm_ud(index),
> -                                       *inst->src[i].reladdr,
> -                                       pull_index);
> +                                       indirect,
> +                                       pull_index * 4);
>              inst->src[i].reladdr = NULL;
>              inst->src[i].stride = 1;
>           } else {
> @@ -3038,13 +3040,11 @@ fs_visitor::lower_uniform_pull_constant_loads()
>           continue;
>
>        if (devinfo->gen >= 7) {
> -         /* The offset arg before was a vec4-aligned byte offset.  We need to
> -          * turn it into a dword offset.
> -          */
> +         /* The offset arg is a vec4-aligned immediate byte offset. */
>           fs_reg const_offset_reg = inst->src[1];
>           assert(const_offset_reg.file == IMM &&
>                  const_offset_reg.type == BRW_REGISTER_TYPE_UD);
> -         const_offset_reg.ud /= 4;
> +         assert(const_offset_reg.ud % 16 == 0);
>
>           fs_reg payload, offset;
>           if (devinfo->gen >= 9) {
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> index c439da2..062ae08 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> @@ -2343,16 +2343,13 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
>        }
>
>        if (has_indirect) {
> -         /* Turn the byte offset into a dword offset. */
> -         fs_reg base_offset = vgrf(glsl_type::int_type);
> -         bld.SHR(base_offset, retype(get_nir_src(instr->src[1]),
> -                                     BRW_REGISTER_TYPE_D),
> -                 brw_imm_d(2));
> +         fs_reg base_offset = retype(get_nir_src(instr->src[1]),
> +                                     BRW_REGISTER_TYPE_D);
>
> -         unsigned vec4_offset = instr->const_index[0] / 4;
> +         unsigned vec4_offset = instr->const_index[0];
>           for (int i = 0; i < instr->num_components; i++)
>              VARYING_PULL_CONSTANT_LOAD(bld, offset(dest, bld, i), surf_index,
> -                                       base_offset, vec4_offset + i);
> +                                       base_offset, vec4_offset + i * 4);
>        } else {
>           fs_reg packed_consts = vgrf(glsl_type::float_type);
>           packed_consts.type = dest.type;
> diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> index f88f8d5..7cb7dd5 100644
> --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> @@ -403,7 +403,7 @@ brw_create_constant_surface(struct brw_context *brw,
>                             uint32_t *out_offset,
>                              bool dword_pitch)
>  {
> -   uint32_t stride = dword_pitch ? 4 : 16;
> +   uint32_t stride = dword_pitch ? 1 : 16;

I've thought dword_pitch was a bad name for a long time, but this
really seals it.

>     uint32_t elements = ALIGN(size, stride) / stride;
>
>     brw->vtbl.emit_buffer_surface_state(brw, out_offset, bo, offset,
> --