basicblock

A basic block is a contiguous sequence of program instructions that contains no incoming control flow transfers except at its entry point and no outgoing control flow transfers except at its exit point. This means that once execution enters a basic block, it proceeds through each instruction in order until the end of the block is reached, without any branches into or out of the middle of the block.

Basic blocks are fundamental to compiler design and program analysis. They serve as the smallest unit for many compiler optimizations. By isolating sequences of code that execute unconditionally, compilers can more easily analyze and transform these blocks to improve performance, reduce code size, or perform other optimizations.

The process of identifying basic blocks within a program's control flow graph is called "basic block decomposition." The entry point of a basic block is defined as the first instruction executed. The exit point is the last instruction. Control flow can branch out from the exit point to other basic blocks, but no other instruction within the block can be the target of a branch. This structural property makes basic blocks amenable to various static analysis techniques.