| /* |
| * Copyright (C) 2019 Collabora, Ltd. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| * |
| * Authors (Collabora): |
| * Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> |
| */ |
| |
| /** |
| * @file |
| * |
| * Flushes undefined SSA values to a zero vector fo the appropriate component |
| * count, to avoid undefined behaviour in the resulting shader. Not required |
| * for conformance as use of uninitialized variables is explicitly left |
| * undefined by the spec. Works around buggy apps, however. |
| * |
| * Call immediately after nir_opt_undef. If called before, larger optimization |
| * opportunities from the former pass will be missed. If called outside of an |
| * optimization loop, constant propagation and algebraic optimizations won't be |
| * able to kick in to reduce stuff consuming the zero. |
| */ |
| |
| #include "compiler/nir/nir.h" |
| #include "compiler/nir/nir_builder.h" |
| |
| bool nir_undef_to_zero(nir_shader *shader); |
| |
| bool |
| nir_undef_to_zero(nir_shader *shader) |
| { |
| bool progress = false; |
| |
| nir_foreach_function(function, shader) { |
| if (!function->impl) continue; |
| |
| nir_builder b; |
| nir_builder_init(&b, function->impl); |
| |
| nir_foreach_block(block, function->impl) { |
| nir_foreach_instr_safe(instr, block) { |
| if (instr->type != nir_instr_type_ssa_undef) continue; |
| |
| nir_ssa_undef_instr *und = nir_instr_as_ssa_undef(instr); |
| |
| /* Get the required size */ |
| unsigned c = und->def.num_components; |
| unsigned s = und->def.bit_size; |
| |
| nir_const_value v[NIR_MAX_VEC_COMPONENTS]; |
| memset(v, 0, sizeof(v)); |
| |
| b.cursor = nir_before_instr(instr); |
| nir_ssa_def *zero = nir_build_imm(&b, c, s, v); |
| nir_src zerosrc = nir_src_for_ssa(zero); |
| |
| nir_ssa_def_rewrite_uses(&und->def, zerosrc); |
| |
| progress |= true; |
| } |
| } |
| |
| nir_metadata_preserve(function->impl, nir_metadata_block_index | nir_metadata_dominance); |
| |
| } |
| |
| return progress; |
| } |
| |
| |