//	    v38 = MOVQstoreconst <mem> {blob} [val=0,off=0] v2 v32
//
// Important: locatePrologEnd is expected to work properly only with
// optimization turned off (e.g. "-N"). If optimization is enabled
// we can't be assured of finding all input arguments spilled in the
// entry block prolog.
func locatePrologEnd(f *Func, needCloCtx bool) (ID, *Value) {

	// returns true if this instruction looks like it moves an ABI