Loop Analysis Framework

include/Analysis/Loop/ and lib/Analysis/Loop/ implement the loop-side analysis stack used by several optimization and verification workflows.

Main components:

• FunctionLoopAnalyses coordinates per-function loop analyses.

• LoopContent and LoopEnvironment summarize loop structure and context.

• LoopDependenceGraph and LoopSCCDAG model intra-loop dependencies.

• LoopIterationSpaceAnalysis reasons about loop bounds and iteration space.

• MemoryCloningAnalysis and SCCDAGAttrs support loop transformations.

This subsystem builds on LLVM loop information but adds Lotus-specific program analysis structures.

Using loop facts

Start from the LLVM loop structure associated with a function, then use the coordinating analysis to obtain the Lotus summaries needed by a client. Iteration-space and dependence information describe what is known about a loop; transformations must still check their own legality conditions before rewriting the IR. Analyses should handle loops without a recoverable bound conservatively rather than treating the absence of a bound as a small loop.

See also CFG Analysis and Optimization.