| /* |
| * Copyright © 2016 Intel Corporation |
| * |
| * 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. |
| */ |
| |
| #ifndef NIR_PHI_BUILDER_H |
| #define NIR_PHI_BUILDER_H |
| |
| #include "nir.h" |
| |
| /** A helper for placing phi nodes in a NIR shader |
| * |
| * Basic usage goes something like this: |
| * |
| * each variable, var, has: |
| * a bitset var.defs of blocks where the variable is defined |
| * a struct nir_phi_builder_value *pb_val |
| * |
| * // initialize bitsets |
| * foreach block: |
| * foreach def of variable var: |
| * var.defs[def.block] = true; |
| * |
| * // initialize phi builder |
| * pb = nir_phi_builder_create() |
| * foreach var: |
| * var.pb_val = nir_phi_builder_add_value(pb, var.defs) |
| * |
| * // Visit each block. This needs to visit dominators first; |
| * // nir_foreach_block() will be ok. |
| * |
| * foreach block: |
| * foreach instruction: |
| * foreach use of variable var: |
| * replace use with nir_phi_builder_get_block_def(var.pb_val) |
| * foreach def of variable var: |
| * create ssa def, register with |
| * nir_phi_builder_set_block_def(var.pb_val) |
| * |
| * nir_phi_builder_finish(pb) |
| */ |
| struct nir_phi_builder; |
| |
| struct nir_phi_builder_value; |
| |
| /* Create a new phi builder. |
| * |
| * While this is fairly cheap, it does allocate some memory and walk the list |
| * of blocks so it's recommended that you only call it once and use it to |
| * build phis for several values. |
| */ |
| struct nir_phi_builder *nir_phi_builder_create(nir_function_impl *impl); |
| |
| /* Register a value with the builder. |
| * |
| * The 'defs' parameter specifies a bitset of blocks in which the given value |
| * is defined. This is used to determine where to place the phi nodes. |
| */ |
| struct nir_phi_builder_value * |
| nir_phi_builder_add_value(struct nir_phi_builder *pb, unsigned num_components, |
| unsigned bit_size, const BITSET_WORD *defs); |
| |
| /* Register a definition for the given value and block. |
| * |
| * It is safe to call this function as many times as you wish for any given |
| * block/value pair. However, it always replaces whatever was there |
| * previously even if that definition is from a phi node. The phi builder |
| * always uses the latest information it has, so you must be careful about the |
| * order in which you register definitions. The final value at the end of the |
| * block must be the last value registered. |
| */ |
| void |
| nir_phi_builder_value_set_block_def(struct nir_phi_builder_value *val, |
| nir_block *block, nir_ssa_def *def); |
| |
| /* Get the definition for the given value in the given block. |
| * |
| * This definition will always be the latest definition known for the given |
| * block. If no definition is immediately available, it will crawl up the |
| * dominance tree and insert phi nodes as needed until it finds one. In the |
| * case that no suitable definition is found, it will return the result of a |
| * nir_ssa_undef_instr with the correct number of components. |
| * |
| * Because this function only uses the latest available information for any |
| * given block, you must have already finished registering definitions for any |
| * blocks that dominate the current block in order to get the correct result. |
| */ |
| nir_ssa_def * |
| nir_phi_builder_value_get_block_def(struct nir_phi_builder_value *val, |
| nir_block *block); |
| |
| /* Finish building phi nodes and free the builder. |
| * |
| * This function does far more than just free memory. Prior to calling |
| * nir_phi_builder_finish, no phi nodes have actually been inserted in the |
| * program. This function is what finishes setting up phi node sources and |
| * adds the phi nodes to the program. |
| */ |
| void nir_phi_builder_finish(struct nir_phi_builder *pb); |
| |
| #endif /* NIR_PHI_BUILDER_H */ |