[CodeGen] Implement RISC-V peephole branch optimization

2 files changed, 35 insertions, 0 deletions

diff --git a/backend/include/rcc/CodeGen/MachinePeepholeOptimizer.h b/backend/include/rcc/CodeGen/MachinePeepholeOptimizer.h
new file mode 100644
index 0000000..9505625
--- /dev/null
+++ b/backend/include/rcc/CodeGen/MachinePeepholeOptimizer.h
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_MACHINEPEEPHOLEOPTIMIZER_H
+#define RCC_CODEGEN_MACHINEPEEPHOLEOPTIMIZER_H
+
+#include "rcc/CodeGen/MachinePassManager.h"
+
+namespace rcc {
+
+class TargetInstrInfo;
+
+class MachinePeepholeOptimizerPass final : public MachineFunctionPass {
+public:
+  explicit MachinePeepholeOptimizerPass(const TargetInstrInfo &Info) noexcept : Info(&Info) {}
+
+  [[nodiscard]] const MachinePassContract &contract() const noexcept override;
+  [[nodiscard]] Expected<MachinePassResult> run(MachineFunction &Function,
+                                                const TargetDescription &Target,
+                                                MachineFunctionAnalysisManager &Analyses) override;
+
+private:
+  [[nodiscard]] Expected<MachinePassResult>
+  runImplementation(MachineFunction &Function, const TargetDescription &Target) const;
+
+  const TargetInstrInfo *Info;
+};
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_MACHINEPEEPHOLEOPTIMIZER_H
diff --git a/backend/include/rcc/CodeGen/TargetInstrInfo.h b/backend/include/rcc/CodeGen/TargetInstrInfo.h
index 8457ede..aada102 100644
--- a/backend/include/rcc/CodeGen/TargetInstrInfo.h
+++ b/backend/include/rcc/CodeGen/TargetInstrInfo.h
@@ -73,6 +73,11 @@ public:
     return false;
   }
 
+  [[nodiscard]] virtual Expected<bool> optimizeCondBranch(MachineInstr &, MachineFunction &,
+                                                          const TargetDescription &) const {
+    return false;
+  }
+
   [[nodiscard]] virtual Expected<bool> tryConvertToThreeAddress(MachineInstr &, std::size_t,
                                                                 std::size_t, MachineFunction &,
                                                                 const TargetDescription &) const {