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 <[email protected]>
Co-authored-by: Rhys Perry <[email protected]>
Co-authored-by: Bas Nieuwenhuizen <[email protected]>
Co-authored-by: Connor Abbott <[email protected]>
Co-authored-by: Michael Schellenberger Costa <[email protected]>
Co-authored-by: Timur Kristóf <[email protected]>

Acked-by: Samuel Pitoiset <[email protected]>
Acked-by: Bas Nieuwenhuizen <[email protected]>

1 files changed, 102 insertions, 0 deletions

diff --git a/src/amd/compiler/aco_dead_code_analysis.cpp b/src/amd/compiler/aco_dead_code_analysis.cpp
new file mode 100644
index 00000000000..f56718f0479
--- /dev/null
+++ b/src/amd/compiler/aco_dead_code_analysis.cpp
@@ -0,0 +1,102 @@
+/*
+ * 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.
+ *
+ */
+
+#include "aco_ir.h"
+
+#include <algorithm>
+
+/*
+ * Implements an analysis pass to determine the number of uses
+ * for each SSA-definition.
+ */
+
+namespace aco {
+namespace {
+
+struct dce_ctx {
+   int current_block;
+   std::vector<uint16_t> uses;
+   std::vector<std::vector<bool>> live;
+
+   dce_ctx(Program* program) : current_block(program->blocks.size() - 1), uses(program->peekAllocationId())
+   {
+      live.reserve(program->blocks.size());
+      for (Block& block : program->blocks)
+         live.emplace_back(block.instructions.size());
+   }
+};
+
+void process_block(dce_ctx& ctx, Block& block)
+{
+   std::vector<bool>& live = ctx.live[block.index];
+   assert(live.size() == block.instructions.size());
+   bool process_predecessors = false;
+   for (int idx = block.instructions.size() - 1; idx >= 0; idx--) {
+      if (live[idx])
+         continue;
+
+      aco_ptr<Instruction>& instr = block.instructions[idx];
+      const bool is_live = instr->definitions.empty() ||
+                           std::any_of(instr->definitions.begin(), instr->definitions.end(),
+                              [&ctx] (const Definition& def) { return !def.isTemp() || ctx.uses[def.tempId()];});
+
+      if (is_live) {
+         for (const Operand& op : instr->operands) {
+            if (op.isTemp()) {
+               if (ctx.uses[op.tempId()] == 0)
+                  process_predecessors = true;
+               ctx.uses[op.tempId()]++;
+            }
+         }
+         live[idx] = true;
+      }
+   }
+
+   if (process_predecessors) {
+      for (unsigned pred_idx : block.linear_preds)
+         ctx.current_block = std::max(ctx.current_block, (int) pred_idx);
+   }
+}
+
+} /* end namespace */
+
+std::vector<uint16_t> dead_code_analysis(Program *program) {
+
+   dce_ctx ctx(program);
+
+   while (ctx.current_block >= 0) {
+      unsigned next_block = ctx.current_block--;
+      process_block(ctx, program->blocks[next_block]);
+   }
+
+   /* add one use to exec to prevent startpgm from being removed */
+   aco_ptr<Instruction>& startpgm = program->blocks[0].instructions[0];
+   assert(startpgm->opcode == aco_opcode::p_startpgm);
+   ctx.uses[startpgm->definitions.back().tempId()]++;
+
+   return ctx.uses;
+}
+
+}
+