Souper is a superoptimizer for LLVM IR designed to automatically discover missed optimization opportunities within LLVM’s mid-end optimizers. By leveraging SMT (Satisfiability Modulo Theories) solvers, Souper symbolically analyzes LLVM Intermediate Representation (IR) to synthesize equivalent, more efficient expressions. It identifies peephole optimizations—small instruction-level improvements—that LLVM’s optimizer may overlook, thereby improving compiled code quality. Souper can operate in multiple modes: as a standalone analysis tool that extracts and solves SMT queries from LLVM bitcode, or as an LLVM optimization pass that applies discovered optimizations directly to the IR. It integrates seamlessly with Clang and LLVM tools and supports caching mechanisms (RAM or Redis) to accelerate repeated analyses. The system can output suggested rewrites for developers or automatically apply transformations, helping compiler engineers improve optimization passes.
Features
- Synthesizes optimized LLVM IR expressions using SMT solvers
- Detects missed peephole and mid-level optimizations automatically
- Functions as both a standalone optimizer and an LLVM opt pass
- Integrates with Clang and LLVM toolchains for easy usage
- Supports caching (RAM or Redis) to improve performance on large builds
- Provides Valgrind-compatible testing and verification for reliability