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

// nilcheckelim eliminates unnecessary nil checks.
// runs on machine-independent code.
func nilcheckelim(f *Func) { … }

const minZeroPage …

var faultOnLoad …

// nilcheckelim2 eliminates unnecessary nil checks.
// Runs after lowering and scheduling.
func nilcheckelim2(f *Func) { … }