<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Jul 22, 2016 at 1:11 AM, Pohjolainen, Topi <<a href="mailto:topi.pohjolainen@intel.com" target="_blank">topi.pohjolainen@intel.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div>On Thu, Jul 21, 2016 at 09:21:53PM -0700, Jason Ekstrand wrote: > On i965, we can't support coordinate offsets for texelFetch or rectangle > textures. Previously, we were doing this with a GLSL pass but we need to > do it in NIR if we want those workarounds for SPIR-V. > > Signed-off-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net" target="_blank">jason@jlekstrand.net</a>> > Cc: "12.0" <<a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a>> > --- > src/compiler/nir/nir.h | 10 ++++++++ > src/compiler/nir/nir_lower_tex.c | 54 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > > diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h > index d0f52b0..45f758c 100644 > --- a/src/compiler/nir/nir.h > +++ b/src/compiler/nir/nir.h > @@ -2405,6 +2405,16 @@ typedef struct nir_lower_tex_options { > unsigned lower_txp; > > /** > + * If true, lower away nir_tex_src_offset for all texelfetch instructions. > + */ > + bool lower_txf_offset; > + > + /** > + * If true, lower away nir_tex_src_offset for all rect textures. > + */ > + bool lower_rect_offset; > + > + /** > * If true, lower rect textures to 2D, using txs to fetch the > * texture dimensions and dividing the texture coords by the > * texture dims to normalize. > diff --git a/src/compiler/nir/nir_lower_tex.c b/src/compiler/nir/nir_lower_tex.c > index 0cf1071..a1280e1 100644 > --- a/src/compiler/nir/nir_lower_tex.c > +++ b/src/compiler/nir/nir_lower_tex.c > @@ -128,6 +128,54 @@ project_src(nir_builder *b, nir_tex_instr *tex) > tex_instr_remove_src(tex, proj_index); > } > > +static bool > +lower_offset(nir_builder *b, nir_tex_instr *tex) > +{ > + int offset_index = tex_instr_find_src(tex, nir_tex_src_offset); </div></div>Could be 'const'. > + if (offset_index < 0) > + return false; > + > + int coord_index = tex_instr_find_src(tex, nir_tex_src_coord); Same here. > + assert(coord_index >= 0); > + > + assert(tex->src[offset_index].src.is_ssa); > + assert(tex->src[coord_index].src.is_ssa); > + nir_ssa_def *offset = tex->src[offset_index].src.ssa; > + nir_ssa_def *coord = tex->src[coord_index].src.ssa; In principle, it looks these could be declared constants as well: const nir_ssa_def * const offset = tex->src[offset_index].src.ssa; const nir_ssa_def * const coord = tex->src[coord_index].src.ssa; But further digging tells me that they can be only: nir_ssa_def * const offset = tex->src[offset_index].src.ssa; nir_ssa_def * const coord = tex->src[coord_index].src.ssa; Quite a few of the helpers in nir declare their inputs as read-write even though they only read the contents... </blockquote><div> </div><div>I have tried on multiple occasions to make NIR more const-safe. Unfortunately, every attempt only seems to lead to frustration. Some of this is due to limitations in C (which are fixed in C11 which we can't use) that make it very hard to make constructs that can handle either const or non-const. This, in turn, makes it very hard to constify things. There is also the fact that we use a lot of embedded linked lists which make a bunch of things that look like they should be const non-const. I've given up. It's better to not claim any sort of constness than to try and claim it and have it all be lies. </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div><div> > + > + b->cursor = nir_before_instr(&tex->instr); > + > + nir_ssa_def *offset_coord; > + if (nir_tex_instr_src_type(tex, coord_index) == nir_type_float) { > + assert(tex->sampler_dim == GLSL_SAMPLER_DIM_RECT); > + offset_coord = nir_fadd(b, coord, nir_i2f(b, offset)); > + } else { > + offset_coord = nir_iadd(b, coord, offset); > + } > + > + if (tex->is_array) { > + /* The offset is not applied to the array index */ > + if (tex->coord_components == 2) { > + offset_coord = nir_vec2(b, nir_channel(b, offset_coord, 0), > + nir_channel(b, coord, 1)); > + } else if (tex->coord_components == 3) { > + offset_coord = nir_vec3(b, nir_channel(b, offset_coord, 0), > + nir_channel(b, offset_coord, 1), > + nir_channel(b, coord, 2)); > + } else { > + unreachable("Invalid number of components"); > + } > + } > + > + nir_instr_rewrite_src(&tex->instr, &tex->src[coord_index].src, > + nir_src_for_ssa(offset_coord)); > + > + tex_instr_remove_src(tex, offset_index); > + > + return true; > +} > + > + > static nir_ssa_def * > get_texture_size(nir_builder *b, nir_tex_instr *tex) > { > @@ -458,6 +506,12 @@ nir_lower_tex_block(nir_block *block, nir_builder *b, > progress = true; > } > > + if ((tex->op == nir_texop_txf && options->lower_txf_offset) || > + (tex->sampler_dim == GLSL_SAMPLER_DIM_RECT && > + options->lower_rect_offset)) { > + progress = lower_offset(b, tex) || progress; > + } > + > if ((tex->sampler_dim == GLSL_SAMPLER_DIM_RECT) && options->lower_rect) { > lower_rect(b, tex); > progress = true; > -- > 2.5.0.400.gff86faf > </div></div>> _______________________________________________ > mesa-dev mailing list > <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a> > <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div> </div></div>