Opt libload 2

[ZERICO2005]

Proof for the push af \ add hl, 15 \ pop af stuff:
#648 (comment)

        ; Original
        ld      de, Y
        ld      hl, X
        or      a, a
        sbc     hl, de  ; HL = X -  Y, DE = Y
        add     hl, de  ; HL = X     , DE = Y

        ex      de, hl  ; HL = Y     , DE = X
        ld      de, 15  ; HL = Y     , DE =     15
        add     hl, de  ; HL = Y + 15, DE =     15
        ex      de, hl  ; HL =     15, DE = Y + 15
        pop     hl      ; HL =      ?, DE = Y + 15

        ; Optimized
        ld      de, Y
        ld      hl, X
        or      a, a
        sbc     hl, de  ; HL = X -  Y, DE = Y

        ld      hl, 15  ; HL =     15, DE = Y
        add     hl, de  ; HL = Y + 15, DE = Y
        ex      de, hl  ; HL =      Y, DE = Y + 15
        pop     hl      ; HL =      ?, DE = Y + 15

[mateoconlechuga]

The flags are changed, are they not? That's what the push af is for. Just need some more proof

[ZERICO2005]

Here push af \ pop af was removed. call ti.CpHLDE was only used to check if HL == DE, so we only need to preserve the Z flag for the jr nz, .loop branch:

• When jr nz, .loop is taken: All flags are destroyed by cp a, (hl).
• When jr nz, .loop is not taken: move_string_to_end (which uses cpir) destroys Z, P, and V. The Carry flag is unused and destroyed by call ti.ChkFindSym

Therefore, it is safe to remove push af \ pop af as we only need the Z flag for jr nz, .loop