go/ir: don't add copied values as referrers of Copy.Why
@@ -1028,9 +1028,6 @@ func copyValue(v Value, why Instruction, info CopyInfo) *Copy {
if refs := v.Referrers(); refs != nil {
*refs = append(*refs, c)
}
- if refs := why.Referrers(); refs != nil {
- *refs = append(*refs, c)
- }
c.setType(v.Type())
c.setSource(v.Source())
return c
