Create pi-block nodes from strongly connected components.
Declared in <llvm/Analysis/DependenceGraphBuilder.h>
void
createPiBlocks();Apply graph abstraction to groups of nodes that belong to a strongly connected component of the graph to create larger compound nodes called pi-blocks. The purpose of this abstraction is to isolate sets of program elements that need to stay together during codegen and turn the dependence graph into an acyclic graph.