aco: Initial commit of independent AMD compiler

ACO (short for AMD Compiler) is a new compiler backend with the goal to replace
LLVM for Radeon hardware for the RADV driver.

ACO currently supports only VS, PS and CS on VI and Vega.
There are some optimizations missing because of unmerged NIR changes
which may decrease performance.

Full commit history can be found at
https://github.com/daniel-schuermann/mesa/commits/backend

Co-authored-by: Daniel Schürmann <daniel@schuermann.dev>
Co-authored-by: Rhys Perry <pendingchaos02@gmail.com>
Co-authored-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Co-authored-by: Connor Abbott <cwabbott0@gmail.com>
Co-authored-by: Michael Schellenberger Costa <mschellenbergercosta@googlemail.com>
Co-authored-by: Timur Kristóf <timur.kristof@gmail.com>

Acked-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

1 files changed, 241 insertions, 0 deletions

diff --git a/src/amd/compiler/aco_lower_bool_phis.cpp b/src/amd/compiler/aco_lower_bool_phis.cpp
new file mode 100644
index 00000000000..0c56ca07214
--- /dev/null
+++ b/src/amd/compiler/aco_lower_bool_phis.cpp
@@ -0,0 +1,241 @@
+/*
+ * Copyright © 2019 Valve 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.
+ *
+ * Authors:
+ *    Rhys Perry (pendingchaos02@gmail.com)
+ *
+ */
+
+#include <map>
+
+#include "aco_ir.h"
+#include "aco_builder.h"
+
+
+namespace aco {
+
+struct phi_use {
+   Block *block;
+   unsigned phi_def;
+
+   bool operator<(const phi_use& other) const {
+      return std::make_tuple(block, phi_def) <
+             std::make_tuple(other.block, other.phi_def);
+   }
+};
+
+struct ssa_state {
+   std::map<unsigned, unsigned> latest;
+   std::map<unsigned, std::map<phi_use, uint64_t>> phis;
+};
+
+Operand get_ssa(Program *program, unsigned block_idx, ssa_state *state)
+{
+   while (true) {
+      auto pos = state->latest.find(block_idx);
+      if (pos != state->latest.end())
+         return Operand({pos->second, s2});
+
+      Block& block = program->blocks[block_idx];
+      size_t pred = block.linear_preds.size();
+      if (pred == 0) {
+         return Operand(s2);
+      } else if (pred == 1) {
+         block_idx = block.linear_preds[0];
+         continue;
+      } else {
+         unsigned res = program->allocateId();
+         state->latest[block_idx] = res;
+
+         aco_ptr<Pseudo_instruction> phi{create_instruction<Pseudo_instruction>(aco_opcode::p_linear_phi, Format::PSEUDO, pred, 1)};
+         for (unsigned i = 0; i < pred; i++) {
+            phi->operands[i] = get_ssa(program, block.linear_preds[i], state);
+            if (phi->operands[i].isTemp()) {
+               assert(i < 64);
+               state->phis[phi->operands[i].tempId()][(phi_use){&block, res}] |= (uint64_t)1 << i;
+            }
+         }
+         phi->definitions[0] = Definition(Temp{res, s2});
+         block.instructions.emplace(block.instructions.begin(), std::move(phi));
+
+         return Operand({res, s2});
+      }
+   }
+}
+
+void update_phi(Program *program, ssa_state *state, Block *block, unsigned phi_def, uint64_t operand_mask) {
+   for (auto& phi : block->instructions) {
+      if (phi->opcode != aco_opcode::p_phi && phi->opcode != aco_opcode::p_linear_phi)
+         break;
+      if (phi->opcode != aco_opcode::p_linear_phi)
+         continue;
+      if (phi->definitions[0].tempId() != phi_def)
+         continue;
+      assert(ffsll(operand_mask) <= phi->operands.size());
+
+      uint64_t operands = operand_mask;
+      while (operands) {
+         unsigned operand = u_bit_scan64(&operands);
+         Operand new_operand = get_ssa(program, block->linear_preds[operand], state);
+         phi->operands[operand] = new_operand;
+         if (!new_operand.isUndefined())
+            state->phis[new_operand.tempId()][(phi_use){block, phi_def}] |= (uint64_t)1 << operand;
+      }
+      return;
+   }
+   assert(false);
+}
+
+Temp write_ssa(Program *program, Block *block, ssa_state *state, unsigned previous) {
+   unsigned id = program->allocateId();
+   state->latest[block->index] = id;
+
+   /* update phis */
+   if (previous) {
+      std::map<phi_use, uint64_t> phis;
+      phis.swap(state->phis[previous]);
+      for (auto& phi : phis)
+         update_phi(program, state, phi.first.block, phi.first.phi_def, phi.second);
+   }
+
+   return {id, s2};
+}
+
+void insert_before_branch(Block *block, aco_ptr<Instruction> instr)
+{
+   int end = block->instructions.size() - 1;
+   if (block->instructions[end]->format == Format::PSEUDO_BRANCH)
+      block->instructions.emplace(std::prev(block->instructions.end()), std::move(instr));
+   else
+      block->instructions.emplace_back(std::move(instr));
+}
+
+void insert_before_logical_end(Block *block, aco_ptr<Instruction> instr)
+{
+   for (int i = block->instructions.size() - 1; i >= 0; --i) {
+      if (block->instructions[i]->opcode == aco_opcode::p_logical_end) {
+         block->instructions.emplace(std::next(block->instructions.begin(), i), std::move(instr));
+         return;
+      }
+   }
+   insert_before_branch(block, std::move(instr));
+}
+
+aco_ptr<Instruction> lower_divergent_bool_phi(Program *program, Block *block, aco_ptr<Instruction>& phi)
+{
+   Builder bld(program);
+
+   ssa_state state;
+   for (unsigned i = 0; i < phi->operands.size(); i++) {
+      Block *pred = &program->blocks[block->logical_preds[i]];
+
+      if (phi->operands[i].isUndefined())
+         continue;
+
+      assert(phi->operands[i].isTemp());
+      Temp phi_src = phi->operands[i].getTemp();
+      if (phi_src.regClass() == s1) {
+         Temp new_phi_src = bld.tmp(s2);
+         insert_before_logical_end(pred,
+            bld.sop2(aco_opcode::s_cselect_b64, Definition(new_phi_src),
+                     Operand((uint32_t)-1), Operand(0u), bld.scc(phi_src)).get_ptr());
+         phi_src = new_phi_src;
+      }
+      assert(phi_src.regClass() == s2);
+
+      Operand cur = get_ssa(program, pred->index, &state);
+      Temp new_cur = write_ssa(program, pred, &state, cur.isTemp() ? cur.tempId() : 0);
+
+      if (cur.isUndefined()) {
+         insert_before_logical_end(pred, bld.sop1(aco_opcode::s_mov_b64, Definition(new_cur), phi_src).get_ptr());
+      } else {
+         Temp tmp1 = bld.tmp(s2), tmp2 = bld.tmp(s2);
+         insert_before_logical_end(pred,
+            bld.sop2(aco_opcode::s_andn2_b64, Definition(tmp1), bld.def(s1, scc),
+                     cur, Operand(exec, s2)).get_ptr());
+         insert_before_logical_end(pred,
+            bld.sop2(aco_opcode::s_and_b64, Definition(tmp2), bld.def(s1, scc),
+                     phi_src, Operand(exec, s2)).get_ptr());
+         insert_before_logical_end(pred,
+            bld.sop2(aco_opcode::s_or_b64, Definition(new_cur), bld.def(s1, scc),
+                     tmp1, tmp2).get_ptr());
+      }
+   }
+
+   return bld.sop1(aco_opcode::s_mov_b64, phi->definitions[0], get_ssa(program, block->index, &state)).get_ptr();
+}
+
+void lower_linear_bool_phi(Program *program, Block *block, aco_ptr<Instruction>& phi)
+{
+   Builder bld(program);
+
+   for (unsigned i = 0; i < phi->operands.size(); i++) {
+      if (!phi->operands[i].isTemp())
+         continue;
+
+      Temp phi_src = phi->operands[i].getTemp();
+      if (phi_src.regClass() == s2) {
+         Temp new_phi_src = bld.tmp(s1);
+         insert_before_logical_end(&program->blocks[block->linear_preds[i]],
+            bld.sopc(aco_opcode::s_cmp_lg_u64, bld.scc(Definition(new_phi_src)),
+                     Operand(0u), phi_src).get_ptr());
+         phi->operands[i].setTemp(new_phi_src);
+      }
+   }
+}
+
+void lower_bool_phis(Program* program)
+{
+   for (Block& block : program->blocks) {
+      std::vector<aco_ptr<Instruction>> instructions;
+      std::vector<aco_ptr<Instruction>> non_phi;
+      instructions.swap(block.instructions);
+      block.instructions.reserve(instructions.size());
+      unsigned i = 0;
+      for (; i < instructions.size(); i++)
+      {
+         aco_ptr<Instruction>& phi = instructions[i];
+         if (phi->opcode != aco_opcode::p_phi && phi->opcode != aco_opcode::p_linear_phi)
+            break;
+         if (phi->opcode == aco_opcode::p_phi && phi->definitions[0].regClass() == s2) {
+            non_phi.emplace_back(std::move(lower_divergent_bool_phi(program, &block, phi)));
+         } else if (phi->opcode == aco_opcode::p_linear_phi && phi->definitions[0].regClass() == s1) {
+            /* if it's a valid non-boolean phi, this should be a no-op */
+            lower_linear_bool_phi(program, &block, phi);
+            block.instructions.emplace_back(std::move(phi));
+         } else {
+            block.instructions.emplace_back(std::move(phi));
+         }
+      }
+      for (auto&& instr : non_phi) {
+         assert(instr->opcode != aco_opcode::p_phi && instr->opcode != aco_opcode::p_linear_phi);
+         block.instructions.emplace_back(std::move(instr));
+      }
+      for (; i < instructions.size(); i++) {
+         aco_ptr<Instruction> instr = std::move(instructions[i]);
+         assert(instr->opcode != aco_opcode::p_phi && instr->opcode != aco_opcode::p_linear_phi);
+         block.instructions.emplace_back(std::move(instr));
+      }
+   }
+}
+
+}