| /* |
| * Copyright (C) 2019 Ryan Houdek <Sonicadvance1@gmail.com> |
| * |
| * 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. |
| */ |
| |
| #include "bifrost_opts.h" |
| #include "compiler_defines.h" |
| |
| bool |
| bifrost_opt_branch_fusion(compiler_context *ctx, bifrost_block *block) |
| { |
| bool progress = false; |
| mir_foreach_instr_in_block_safe(block, instr) { |
| if (instr->op != op_branch) continue; |
| if (instr->literal_args[0] != BR_COND_EQ) continue; |
| |
| unsigned src1 = instr->ssa_args.src0; |
| |
| // Only work on SSA values |
| if (src1 >= SSA_FIXED_MINIMUM) continue; |
| |
| // Find the source for this conditional branch instruction |
| // It'll be a CSEL instruction |
| // If it's comparision is one of the ops that our conditional branch supports |
| // then we can merge the two |
| mir_foreach_instr_in_block_from_rev(block, next_instr, instr) { |
| if (next_instr->op != op_csel_i32) continue; |
| |
| if (next_instr->ssa_args.dest == src1) { |
| // We found the CSEL instruction that is the source here |
| // Check its condition to make sure it matches what we can fuse |
| unsigned cond = next_instr->literal_args[0]; |
| if (cond == CSEL_IEQ) { |
| // This CSEL is doing an IEQ for our conditional branch doing EQ |
| // We can just emit a conditional branch that does the comparison |
| struct bifrost_instruction new_instr = { |
| .op = op_branch, |
| .dest_components = 0, |
| .ssa_args = { |
| .dest = SSA_INVALID_VALUE, |
| .src0 = next_instr->ssa_args.src0, |
| .src1 = next_instr->ssa_args.src1, |
| .src2 = SSA_INVALID_VALUE, |
| .src3 = SSA_INVALID_VALUE, |
| }, |
| .literal_args[0] = BR_COND_EQ, |
| .literal_args[1] = instr->literal_args[1], |
| }; |
| mir_insert_instr_before(instr, new_instr); |
| mir_remove_instr(instr); |
| progress |= true; |
| break; |
| } |
| } |
| } |
| } |
| |
| return progress; |
| } |
| |