go/src/cmd/compile/internal/ssa/layout.go

// layout orders basic blocks in f with the goal of minimizing control flow instructions.
// After this phase returns, the order of f.Blocks matters and is the order
// in which those blocks will appear in the assembly output.
func layout(f *Func) { … }

// Register allocation may use a different order which has constraints
// imposed by the linear-scan algorithm.
func layoutRegallocOrder(f *Func) []*Block { … }

func layoutOrder(f *Func) []*Block { … }