Question of implementation of EBB in LLVM

GCC in the sched2 stage, there are two kinds of scheduling scheme:
(1)EBB (extended basic block) based method,when turn on option -fsched2-use-superblocks.
(2)single basic block region based method.
I want to konw the implementation of EBB in LLVM, is it implementation in LLVM?and in which stage?

GCC in the sched2 stage, there are two kinds of scheduling scheme:
(1)EBB (extended basic block) based method,when turn on option -fsched2-use-superblocks.
(2)single basic block region based method.
I want to konw the implementation of EBB in LLVM, is it implementation in LLVM?and in which stage?

Currently there is no global scheduling in LLVM.

Evan