From fe9a6c0f14aa3ca6dfb1c7480871c95838b5cf14 Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Mon, 11 Mar 2019 18:58:24 -0500 Subject: [PATCH] nir/builder: Add a vector extract helper This one's a tiny bit better than what we had in spirv_to_nir because it emits a binary tree rather than a linear walk. It also doesn't leave around unneeded bcsel instructions for a constant index and returns an undef for constant OOB access. Reviewed-by: Caio Marcelo de Oliveira Filho --- src/compiler/nir/nir_builder.h | 29 +++++++++++++++++++++++++++++ src/compiler/spirv/spirv_to_nir.c | 7 +------ 2 files changed, 30 insertions(+), 6 deletions(-) diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h index 4b4d1eef462..9662cd2a217 100644 --- a/src/compiler/nir/nir_builder.h +++ b/src/compiler/nir/nir_builder.h @@ -569,6 +569,35 @@ nir_channels(nir_builder *b, nir_ssa_def *def, nir_component_mask_t mask) return nir_swizzle(b, def, swizzle, num_channels, false); } +static inline nir_ssa_def * +_nir_vector_extract_helper(nir_builder *b, nir_ssa_def *vec, nir_ssa_def *c, + unsigned start, unsigned end) +{ + if (start == end - 1) { + return nir_channel(b, vec, start); + } else { + unsigned mid = start + (end - start) / 2; + return nir_bcsel(b, nir_ilt(b, c, nir_imm_int(b, mid)), + _nir_vector_extract_helper(b, vec, c, start, mid), + _nir_vector_extract_helper(b, vec, c, mid, end)); + } +} + +static inline nir_ssa_def * +nir_vector_extract(nir_builder *b, nir_ssa_def *vec, nir_ssa_def *c) +{ + nir_src c_src = nir_src_for_ssa(c); + if (nir_src_is_const(c_src)) { + unsigned c_const = nir_src_as_uint(c_src); + if (c_const < vec->num_components) + return nir_channel(b, vec, c_const); + else + return nir_ssa_undef(b, 1, vec->bit_size); + } else { + return _nir_vector_extract_helper(b, vec, c, 0, vec->num_components); + } +} + static inline nir_ssa_def * nir_i2i(nir_builder *build, nir_ssa_def *x, unsigned dest_bit_size) { diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c index da0f2dcd805..3b7f8d8a9ac 100644 --- a/src/compiler/spirv/spirv_to_nir.c +++ b/src/compiler/spirv/spirv_to_nir.c @@ -3047,12 +3047,7 @@ nir_ssa_def * vtn_vector_extract_dynamic(struct vtn_builder *b, nir_ssa_def *src, nir_ssa_def *index) { - nir_ssa_def *dest = vtn_vector_extract(b, src, 0); - for (unsigned i = 1; i < src->num_components; i++) - dest = nir_bcsel(&b->nb, nir_ieq_imm(&b->nb, index, i), - vtn_vector_extract(b, src, i), dest); - - return dest; + return nir_vector_extract(&b->nb, src, nir_i2i(&b->nb, index, 32)); } nir_ssa_def * -- 2.30.2