Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net> On Mon, Jul 9, 2018 at 5:21 AM Alejandro Piñeiro <apinhe...@igalia.com> wrote:
> From: Neil Roberts <nrobe...@igalia.com> > > If the glsl is something like this: > > in vec4 some_input; > interpolateAtCentroid(some_input[idx]) > > then it now gets generated as if it were: > > interpolateAtCentroid(some_input)[idx] > > This is necessary because the index will get generated as a series of > nir_bcsel instructions so it would no longer be an input variable. It > is similar to what is done for GLSL in ca63a5ed3e9efb2bd645b42. > > Although I can’t find anything explicit in the Vulkan specs to say > this should be allowed, the SPIR-V spec just says “the operand > interpolant must be a pointer to the Input Storage Class”, which I > guess doesn’t rule out any type of pointer to an input. > > This was found using the spec/glsl-4.40/execution/fs-interpolateAt* > Piglit tests with the ARB_gl_spirv branch. > > Signed-off-by: Neil Roberts <nrobe...@igalia.com> > Signed-off-by: Alejandro Piñeiro <apinhe...@igalia.com> > > v2: update after nir_deref_instr land on master. Implemented by > Alejandro Piñeiro. Special thanks to Jason Ekstrand for guidance > at the new nir_deref_instr world. > --- > > Although this was initially detected while testing the ARB_gl_spirv > ongoing implementation, as v1, this can be tested on Vulkan using > vkrunner: > > git clone https://github.com/Igalia/vkrunner.git -b tests > cd vkrunner && ./autogen.sh && make > ./src/vkrunner examples/interpolation/*.shader_test > > src/compiler/spirv/vtn_glsl450.c | 38 > +++++++++++++++++++++++++++++++++----- > 1 file changed, 33 insertions(+), 5 deletions(-) > > diff --git a/src/compiler/spirv/vtn_glsl450.c > b/src/compiler/spirv/vtn_glsl450.c > index 7f941ceeb0d..8393450f2f4 100644 > --- a/src/compiler/spirv/vtn_glsl450.c > +++ b/src/compiler/spirv/vtn_glsl450.c > @@ -802,7 +802,22 @@ handle_glsl450_interpolation(struct vtn_builder *b, > enum GLSLstd450 opcode, > > struct vtn_pointer *ptr = > vtn_value(b, w[5], vtn_value_type_pointer)->pointer; > - intrin->src[0] = nir_src_for_ssa(&vtn_pointer_to_deref(b, > ptr)->dest.ssa); > + nir_deref_instr *deref = vtn_pointer_to_deref(b, ptr); > + > + /* If the value we are interpolating has an index into a vector then > + * interpolate the vector and index the result of that instead. This is > + * necessary because the index will get generated as a series of > nir_bcsel > + * instructions so it would no longer be an input variable. > + */ > + const bool vec_array_deref = deref->deref_type == nir_deref_type_array > && > + glsl_type_is_vector(nir_deref_instr_parent(deref)->type); > + > + nir_deref_instr *vec_deref = NULL; > + if (vec_array_deref) { > + vec_deref = deref; > + deref = nir_deref_instr_parent(deref); > + } > + intrin->src[0] = nir_src_for_ssa(&deref->dest.ssa); > > switch (opcode) { > case GLSLstd450InterpolateAtCentroid: > @@ -815,13 +830,26 @@ handle_glsl450_interpolation(struct vtn_builder *b, > enum GLSLstd450 opcode, > vtn_fail("Invalid opcode"); > } > > - intrin->num_components = glsl_get_vector_elements(dest_type); > + intrin->num_components = glsl_get_vector_elements(deref->type); > nir_ssa_dest_init(&intrin->instr, &intrin->dest, > - glsl_get_vector_elements(dest_type), > - glsl_get_bit_size(dest_type), NULL); > - val->ssa->def = &intrin->dest.ssa; > + glsl_get_vector_elements(deref->type), > + glsl_get_bit_size(deref->type), NULL); > > nir_builder_instr_insert(&b->nb, &intrin->instr); > + > + if (vec_array_deref) { > + assert(vec_deref); > + nir_const_value *const_index = > nir_src_as_const_value(vec_deref->arr.index); > + if (const_index) { > + val->ssa->def = vtn_vector_extract(b, &intrin->dest.ssa, > + const_index->u32[0]); > + } else { > + val->ssa->def = vtn_vector_extract_dynamic(b, &intrin->dest.ssa, > + > vec_deref->arr.index.ssa); > + } > + } else { > + val->ssa->def = &intrin->dest.ssa; > + } > } > > bool > -- > 2.14.1 > >
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