<div dir="ltr">Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> </div> <div class="gmail_quote"><div dir="ltr">On Mon, Jul 9, 2018 at 5:21 AM Alejandro Piñeiro <<a href="mailto:apinheiro@igalia.com">apinheiro@igalia.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">From: Neil Roberts <<a href="mailto:nroberts@igalia.com" target="_blank">nroberts@igalia.com</a>> 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 <<a href="mailto:nroberts@igalia.com" target="_blank">nroberts@igalia.com</a>> Signed-off-by: Alejandro Piñeiro <<a href="mailto:apinheiro@igalia.com" target="_blank">apinheiro@igalia.com</a>> 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 <a href="https://github.com/Igalia/vkrunner.git" rel="noreferrer" target="_blank">https://github.com/Igalia/vkrunner.git</a> -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 </blockquote></div>