// of an If block can be derived from its predecessor If block, in
// some such cases, we can redirect the predecessor If block to the
// corresponding successor block directly. For example:
//
//	p:
//	  v11 = Less64 <bool> v10 v8
//	  If v11 goto b else u
//	b: <- p ...
//	  v17 = Leq64 <bool> v10 v8
//	  If v17 goto s else o
//
// We can redirect p to s directly.
//