diff --git a/src/cc65/coptlong.c b/src/cc65/coptlong.c
index 29cf4d353..7e30ef42e 100644
--- a/src/cc65/coptlong.c
+++ b/src/cc65/coptlong.c
@@ -120,9 +120,13 @@ unsigned OptLongAssign (CodeSeg* S)
               !CS_RangeHasLabel(S, I, 12)) {
 
               L[1]->AM = L[11]->AM;
+              L[1]->Size = L[11]->Size;
+              L[1]->Flags = L[11]->Flags;
               CE_SetArg(L[1], L[11]->Arg);
 
               L[3]->AM = L[9]->AM;
+              L[3]->Size = L[9]->Size;
+              L[3]->Flags = L[9]->Flags;
               CE_SetArg(L[3], L[9]->Arg);
 
               CS_DelEntries (S, I+8, 4);
@@ -211,9 +215,13 @@ unsigned OptLongCopy (CodeSeg* S)
               !CS_RangeHasLabel(S, I, 12)) {
 
               L[1]->AM = L[11]->AM;
+              L[1]->Size = L[11]->Size;
+              L[1]->Flags = L[11]->Flags;
               CE_SetArg(L[1], L[11]->Arg);
 
               L[3]->AM = L[9]->AM;
+              L[3]->Size = L[9]->Size;
+              L[3]->Flags = L[9]->Flags;
               CE_SetArg(L[3], L[9]->Arg);
 
               CS_DelEntries (S, I+8, 4);