From ba1907f040e9d61be932a8e098061d94d4ba30cb Mon Sep 17 00:00:00 2001 From: Iago Toral Quiroga Date: Tue, 19 Apr 2016 12:59:47 +0200 Subject: [PATCH] i965/fs: optimize pack double When we are actually creating a double using values obtained from a previous unpack operation we can bypass the unpack and source from the original double value directly. v2: - Style changes (Topi) - Bail is parent instruction's src is not SSA (Connor) v3: Use subscript() instead of stride() (Curro) Reviewed-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 29 ++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp index 5b5a7667bbb..afa3308135e 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp @@ -1099,6 +1099,35 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr) break; case nir_op_pack_double_2x32_split: + /* Optimize the common case where we are re-packing a double with + * the result of a previous double unpack. In this case we can take the + * 32-bit value to use in the re-pack from the original double and bypass + * the unpack operation. + */ + for (int i = 0; i < 2; i++) { + if (instr->src[i].src.is_ssa) + continue; + + const nir_instr *parent_instr = instr->src[i].src.ssa->parent_instr; + if (parent_instr->type == nir_instr_type_alu) + continue; + + const nir_alu_instr *alu_parent = nir_instr_as_alu(parent_instr); + if (alu_parent->op == nir_op_unpack_double_2x32_split_x || + alu_parent->op == nir_op_unpack_double_2x32_split_y) + continue; + + if (!alu_parent->src[0].src.is_ssa) + continue; + + op[i] = get_nir_src(alu_parent->src[0].src); + op[i] = offset(retype(op[i], BRW_REGISTER_TYPE_DF), bld, + alu_parent->src[0].swizzle[channel]); + if (alu_parent->op == nir_op_unpack_double_2x32_split_y) + op[i] = subscript(op[i], BRW_REGISTER_TYPE_UD, 1); + else + op[i] = subscript(op[i], BRW_REGISTER_TYPE_UD, 0); + } bld.emit(FS_OPCODE_PACK, result, op[0], op[1]); break; -- 2.30.2