// lookupVarOutgoing finds the variable's value at the end of block b.
func (s *simplePhiState) lookupVarOutgoing(b *ssa.Block, t ssa.Type, var_ *Node, line int32) *ssa.Value {
for {
if v := s.defvars[b.ID][var_]; v != nil {
return v
}
// The variable is not defined by b and we haven't looked it up yet.
// If b has exactly one predecessor, loop to look it up there.
// Otherwise, give up and insert a new FwdRef and resolve it later.
if len(b.Preds) != 1 {
break
}
b = b.Preds[0].Block()
}
// Generate a FwdRef for the variable and return that.
v := b.NewValue0A(line, ssa.OpFwdRef, t, var_)
s.defvars[b.ID][var_] = v
s.s.addNamedValue(var_, v)
s.fwdrefs = append(s.fwdrefs, v)
return v
}
