Z80 peephole improvements - Implemented RFE #1919415, #1861376, #1880202, #1914434...

[fw/sdcc] / src / z80 / peeph-z80.def

// peeph.def - Common Z80 and gbz80 peephole rules
//
// These peepholes could be potentially moved to peeph.def, but a GBZ80 expert
// Should have a look at them before.
//
// (c) Philipp Klaus Krause (pkk@spth.de, philipp@colecovision.eu) 2006 - 2008
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option) any
// later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

replace restart {
        ld      %1,%1
} by {
        ; peephole -1 removed redundant load.
} if notVolatile(%1)

// This one doesn't work currently since the peephole optimizer can't match lines generated by multiline macros: Bug #1570701
//replace restart {
//      pop     af
//      ld      sp,%1
//} by {
//      ; peephole -1a eleminated dead pop.
//      ld      sp,%1
//} if notUsed('a')

replace restart {
        ld      %1,%2
} by {
        ; peephole 0a removed dead load from %2 into %1.
} if notVolatile(%1), notUsed(%1)
// Should probably check for notVolatile(%2), too, but gives many false positives and no regression tests fail.

replace restart {
        ld      %1,%2
        ld      a,%1
} by {
        ; peephole 0b loaded %2 into a directly instead of going through %1.
        ld      a,%2
} if notVolatile(%1), notUsed(%1)

replace restart {
        ld      %1,%2 (%3)
        ld      a,%1
} by {
        ; peephole 0c loaded %2 (%3) into a directly instead of going through %1.
        ld      a,%2 (%3)
} if notVolatile(%1), notUsed(%1)

replace restart {
        ld      %1,#%2
        ld      a,%3 (%1)
} by {
        ; peephole 0d loaded %2 into a directly instead of going through %1.
        ld      a,(#%2 + %3)
} if notUsed(%1)

replace restart {
        srl     %1
        ld      a,%1
} by {
        ld      a,%1
        ; peephole 0e shifted in a instead of %1.
        srl     a
} if notVolatile(%1), notUsed(%1)

replace restart {
        ld      %1,(hl)
        ld      a,%2 (%3)
        sub     a,%1
} by {
        ld      a,%2 (%3)
        ; peephole 0f used (hl) in sub directly instead of going through %1.
        sub     a,(hl)
} if notVolatile(%1), notUsed(%1)

replace restart {
        inc     de
        inc     de
        ld      l,e
        ld      h,d
} by {
        ld      l,e
        ld      h,d
        ; peephole 0g incremented in hl instead of de.
        inc     hl
        inc     hl
} if notUsed('de')

replace restart {
        inc     de
        ld      l,e
        ld      h,d
} by {
        ld      l,e
        ld      h,d
        ; peephole 0h incremented in hl instead of de.
        inc     hl
} if notUsed('de')

replace restart {
        ld      e,%1
        ld      d,%2
        ld      l,e
        ld      h,d
} by {
        ; peephole 0i loaded %2%1 into hl directly instead of going through de.
        ld      l,%1
        ld      h,%2
} if notUsed('de')

replace restart {
        ld      bc,#%2 + %3
        ld      a,(bc)
        ld      c,a
} by {
        ; peephole 0j used hl for #%2 + %3 instead of bc, not going through a.
        ld      hl,#%2 + %3
        ld      c,(hl)
} if notUsed('a'), notUsed('hl')

replace restart {
        ex      de,hl
        push    hl
} by {
        ; peephole 0k pushed de directly instead of going through hl.
        push    de
} if notUsed('de'), notUsed('hl')

replace restart {
        ex      de,hl
        push    bc
        push    de
} by {
        ; peephole 0l pushed hl directly instead of going through de.
        push    bc
        push    hl
} if notUsed('de'), notUsed('hl')

replace restart {
        ld      l,c
        ld      h,b
        push    hl
} by {
        ; peephole 0m pushed bc directly instead of going through hl.
        push    bc
} if notUsed('hl')

replace restart {
        ld      c,a
        push    de
        ld      a,c
} by {
        ; peephole 0n removed redundant load of a through c.
        push    de
} if notUsed('c')

replace restart {
        ld      c,e
        ld      b,d
        ld      a,(bc)
} by {
        ; peephole 0o used de directly instead of going through bc.
        ld      a,(de)
} if notUsed('bc')

replace restart {
        pop     de
        ld      l,e
        ld      h,d
} by {
        ; peephole 0p popped hl directly instead of going through de.
        pop     hl
} if notUsed('de')

replace restart {
        ld      %1,a
        ld      %2 (%3),%1
} by {
        ; peephole 0q loaded a into %2 (%3) directly instead of going through %1.
        ld      %2 (%3),a
} if notVolatile(%1), notUsed(%1)

replace restart {
        ld      %1 (ix),%2
        ld      %3, %1 (ix)
} by {
        ; peephole 0r loaded %3 from %2 instead of going through %1 (ix).
        ld      %1 (ix),%2
        ld      %3, %2
}
// Don't need to check for volatile, since ix is used for the stack.

replace restart {
        ld      %1, %2 (%3)
        ld      b, %1
} by {
        ; peephole 0s loaded b from %2 (%3) instead of going through %1.
        ld      b, %2 (%3)
} if notVolatile(%1), notUsed(%1)

replace restart {
        ld      %1,a
        ld      %2,%3
        ld      %4,%1
} by {
        ; peephole 0t loaded %4 from a instead of going through %1.
        ld      %1,a
        ld      %2,%3
        ld      %4,a
} if notVolatile(%1), operandsNotRelated(%1 %3), operandsNotRelated(%1 %2)

replace restart {
        ld      %1,(hl)
        ld      e,%1
} by {
        ; peephole 0u loaded e from (hl) instead of going through %1.
        ld      e,(hl)
} if notUsed(%1)

replace restart {
        ld      %1,l
        ld      %2 (%3),%1
} by {  
        ; peephole 0v loaded %2 (%3) from l instead of going through %1.
        ld      %2 (%3),l
} if notUsed(%1)

replace restart {
        ld      l,%1 (ix)
        ld      h,%2 (ix)
        ld      %3,(hl)
        srl     %3
        ld      l,%1 (ix)
        ld      h,%2 (ix)
        ld      (hl),%3
} by {  
        ld      l,%1 (ix)
        ld      h,%2 (ix)
        ; peephole 0w shifted (hl) in place.
        srl     (hl)
        ld      %3,(hl)
} if notVolatile(%3)
// Don't check for volatile since ix points to the stack.

replace restart {
        push    af
        inc     sp
        ld      a,e
        push    af
        inc     sp
} by {
        ; peephole 0x pushed de instead of pushing a twice.
        ld      d,a
        push    de
} if notUsed('d'), notUsed('a')

replace restart {
        push    af
        inc     sp
        ld      a,c
        push    af
        inc     sp
} by {
        ; peephole 0y pushed bc instead of pushing a twice.
        ld      b,a
        push    bc
} if notUsed('b'), notUsed('a')

replace restart {
        ld      a,#%1
        ld      d,a
} by {
        ; peephole 0z loaded #%1 into d directly instead of going through a.
        ld      d,#%1
} if notUsed('a')

replace restart {
        ld      a,%1 (ix)
        push    af
        inc     sp
        ld      a,%2 (ix)
        push    af
        inc     sp
} by {
        ; peephole 0za pushed %1 (ix), %2(ix) through hl instead of af.
        ld      h,%1 (ix)
        ld      l,%2 (ix)
        push    hl
} if notUsed('a'), notUsed('hl')

replace restart {
        ld      c,l
        ld      b,h
        push    bc
} by {
        ; peephole 0zb pushed hl instead of bc.
        push    hl
} if notUsed('bc')

// Doesn'T work due to bug #1947081
//replace restart {
//      pop     %1
//      push    %1
//} by {
//      ; peephole 0zc eleminated dead pop/push pair.
//} if notUsed(%1)

replace restart {
        ld      iy,#%1
        or      a,%2 (iy)
} by {
        ; peephole 0zd used hl instead of iy.
        ld      hl,#%1 + %2
        or      a,(hl)
} if notUsed('iy'), notUsed('hl')

replace restart {
        ld      iy,#%1
        ld      %2,%3 (%4)
} by {
        ; peephole 0ze used hl instead of iy.
        ld      hl,#%1 + %3
        ld      %2,(hl)
} if notUsed('iy'), notUsed('hl')

replace restart {
        ld      iy,#%1
        ld      %2 (%3), %4
} by {
        ; peephole 0zf used hl instead of iy.
        ld      hl,#%1 + %2
        ld      (hl), %4
} if notUsed('iy'), notUsed('hl')

replace restart {
        ld      e,l
        ld      d,h
        ld      %1,(de)
} by {
        ; peephole 0zg loaded %1 from (hl) directly instead of going through (de).
        ld      %1,(hl)
} if notUsed('de')

replace restart {
        ld      c,l
        ld      b,h
        ld      %1,(bc)
} by {
        ; peephole 0zh loaded %1 from (hl) directly instead of going through (bc).
        ld      %1,(hl)
} if notUsed('bc')

replace restart {
        ld      c,l
        ld      b,h
        inc     bc
} by {
        ; peephole 0zi incremented in hl instead of bc.
        inc     hl
        ld      c,l
        ld      b,h
} if notUsed('hl')

replace restart {
        ld      a,%1 (%2)
        bit     %3,a
} by {
        ; peephole 0zj tested bit of %1 (%2) directly instead of going through a.
        bit     %3,%1 (%2)
} if notUsed('a')

replace restart {
        ld      bc, #%1 + %2
        ld      l,c
        ld      h,b
} by {
        ; peephole 0zk stored constant #%1 + %2 into hl directly instead of going through bc.
        ld      hl, #%1 + %2
} if notUsed('bc')

replace restart {
        jp      NC,%1
        jp      %2
%1:
} by {
        jp      C,%2
        ; peephole 3 removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

replace restart {
        jp      C,%1
        jp      %2
%1:
} by {
        jp      NC,%2
        ; peephole 4 removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

replace restart {
        jp      NZ,%1
        jp      %2
%1:
} by {
        jp      Z,%2
        ; peephole 5 removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

replace restart {
        jp      Z,%1
        jp      %2
%1:
} by {
        jp      NZ,%2
        ; peephole 6 removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

replace restart {
        jp      %5
} by {
        jp      %6
        ; peephole 7 redirected jump-to-jump at %5 by jump to %6
} if labelIsUncondJump(), labelRefCountChange(%5 -1), labelRefCountChange(%6 +1)

replace restart {
        jp      %1,%5
} by {
        jp      %1,%6
        ; peephole 8 redirected jump-to-jump at %5 by jump to %6
} if labelIsUncondJump(), labelRefCountChange(%5 -1), labelRefCountChange(%6 +1)

replace restart {
        xor     a,a
        ld      a,#0x00
} by {
        xor     a,a
        ; peephole 10 removed redundant load of 0 into a.
}

replace {
        ld      e,#0x%1
        ld      d,#0x%2
} by {
        ld      de,#0x%2%1
        ; peephole 11 combined constant loads into register pair.
}

replace {
        ld      l,#0x%1
        ld      h,#0x%2
} by {
        ld      hl,#0x%2%1
        ; peephole 12 combined constant loads into register pair.
}

replace {
        ld      c,#0x%1
        ld      b,#0x%2
} by {
        ld      bc,#0x%2%1
        ; peephole 13 combined constant loads into register pair.
}

replace restart {
        ld      %1,a
        ld      a,%1
} by {
        ld      %1,a
        ; peephole 14 removed redundant load from %1 into a.
} if notVolatile(%1)
// This gives many false negatives and without the test no problems are encountered in the regression tests
// Maybe we can try this after 2.7.0 release

replace restart {
        ld      a,%1
        ld      %1,a
} by {
        ld      a,%1
        ; peephole 15 removed redundant load from a into %1.
} if notVolatile(%1)
// This gives many false negatives and without the test no problems are encountered in the regression tests
// Maybe we can try this after 2.7.0 release

replace restart {
        ld      %1,a
        ld      a,%2
        or      a,%1
} by {
        ld      %1,a
        or      a,%2
        ; peephole 17 removed load by reordering or arguments.
} if notVolatile(%1)

replace restart {
        ld      %1,a
        xor     a,a
        or      a,%1
} by {
        ld      %1,a
        or      a,a
        ; peephole 18 used value still in a instead of loading it from %1.
}

replace restart {
        or      a,%1
        or      a,a
} by {
        or      a,%1
        ; peephole 19 removed redundant or after or.
}

replace restart {
        or      a,%1 (%2)
        or      a,a
} by {
        or      a,%1 (%2)
        ; peephole 19a removed redundant or after or.
}

replace restart {
        and     a,%1
        or      a,a
} by {
        and     a,%1
        ; peephole 20 removed redundant or after and.
}

replace restart {
        and     a,%1 (%2)
        or      a,a
} by {
        and     a,%1 (%2)
        ; peephole 20a removed redundant or after and.
}

replace restart {
        xor     a,%1
        or      a,a
} by {
        xor     a,%1
        ; peephole 21 removed redundant or after xor.
}

replace restart {
        xor     a,%1 (%2)
        or      a,a
} by {
        xor     a,%1 (%2)
        ; peephole 21a removed redundant or after xor.
}

replace {
        ld      %1,%2
        ld      a,%2
} by {
        ld      a,%2
        ld      %1,a
        ; peephole 23 load value in a first and use it next
} if notVolatile(%1 %2)

replace restart {
        ld      %1,%2
        ld      %3,%4
        ld      %2,%1
        ld      %4,%3
} by {
        ld      %1,%2
        ld      %3,%4
        ; peephole 24 removed redundant load from %3%1 into %4%2
} if notVolatile(%1 %2 %3 %4)

replace restart {
        ld      a,c
        push    af
        inc     sp
        ld      a,#%2
        push    af
        inc     sp
        call    %3
} by {
        ld      b,c
        ld      c,#%2
        push    bc
        ; peephole 31 moved and pushed arguments c and #%2 through bc instead of pushing them individually.
        call    %3
}

replace restart {
        ld      a,e
        push    af
        inc     sp
        ld      a,#%2
        push    af
        inc     sp
        call    %3
} by {
        ld      d,e
        ld      e,#%2
        push    de
        ; peephole 32 moved and pushed arguments e and #%2 through de instead of pushing them individually.
        call    %3
}

replace restart {
        ld      a,%1
        sub     a,%2
        jp      %3,%4
        ld      a,%1
} by {
        ld      a,%1
        cp      a,%2
        jp      %3,%4
        ; peephole 33 removed load by replacing sub with cp
        assert  a=%1
} if notVolatile(%1)

replace restart {
        assert  a=%1
        sub     a,%2
        jp      %3,%4
        ld      a,%1
} by {
        cp      a,#%2
        jp      %3,%4
        ; peephole 34 removed load by replacing sub with cp
        assert  a=%1
}

replace restart {
        assert  a=%1
} by {
}

replace restart {
        sub     a,#0xFF
        jp      Z,%1
} by {
        inc     a
        ; peephole 35 replaced sub a,#0xFF by inc a.
        jp      Z,%1
}

replace restart {
        sub     a,#0xFF
        jp      NZ,%1
} by {
        inc     a
        ; peephole 36 replaced sub a,#0xFF by inc a.
        jp      NZ,%1
}

replace restart {
        ld      bc,#%1 + %2
        ld      a,c
        add     a,%3
        ld      c,a
        ld      a,b
        adc     a,%4
        ld      b,a
} by {
        ld      a,#<(%1 + %2)
        add     a,%3
        ld      c,a
        ld      a,#>(%1 + %2)
        ; peephole 37 directly used (%1 + %2) in calculation instead of placing it in bc first.
        adc     a,%4
        ld      b,a
}

replace restart {
        ld      de,#%1 + %2
        ld      a,e
        add     a,%3
        ld      e,a
        ld      a,d
        adc     a,%4
        ld      d,a
} by {
        ld      a,#<(%1 + %2)
        add     a,%3
        ld      e,a
        ld      a,#>(%1 + %2)
        ; peephole 38 directly used (%1 + %2) in calculation instead of placing it in de first.
        adc     a,%4
        ld      d,a
}

replace restart {
        rlca
        ld      a,#0x00
        rla
} by {
        rlca
        and     a,#0x01
        ; peephole 39 replaced zero load, rla by and since rlca writes the same value to carry bit and least significant bit.
}

replace restart {
        ld      %1,%2
        push    %1
        pop     %4
        ld      %1,%3
} by {
        ld      %4,%2
        ; peephole 40 moved %2 directly into de instead of going through %1.
        ld      %1,%3
}

replace restart {
        add     a,#0x00
        ld      %2,a
        ld      a,%3
        adc     a,%4
} by {
        ; peephole 41 removed lower part of multibyte addition.
        ld      %2,a
        ld      a,%3
        add     a,%4
}

replace restart {
        ld      %1,a
        ld      a,%2
        add     a,%1
} by {
        ; peephole 42 removed loads by exploiting commutativity of addition.
        add     a,%2
} if notVolatile(%1), notUsed(%1), operandsNotRelated(%2 '(bc)' '(de)')

replace restart {
        ld      %1 (ix),a
        ld      a,#%2
        add     a,%1 (ix)
} by {
        ld      %1 (ix),a
        ; peephole 42a removed loads by exploiting commutativity of addition.
        add     a,#%2
}
// Don't need to check for volatile, since ix is used to access the stack.

// sdcc does not use the H flag. sla resets it, while add sets it.
// To ensure that the state of the H flag is not changed by this
// peephole uncomment the add %3, %4 at the end (since it overwrite the H flag).
replace restart {
        ld      %1, a
        sla     %1
        ld      a, %2
        //add   %3, %4
} by {
        add     a, a
        ; peephole 42b shifts in accumulator insted of %1
        ld      %1, a
        ld      a, %2
        //add   %3, %4
}

replace restart {
        ld      %1,a
        ld      a,%2
        add     a,%1
} by {
        ld      %1, a
        ; peephole 43 removed load by exploiting commutativity of addition.
        add     a,%2
} if operandsNotRelated(%2 '(bc)' '(de)')

replace restart {
        ld      c,l
        ld      b,h
        ld      hl,#%1
        add     hl,bc
} by {
        ; peephole 43a removed loads by exploiting commutativity of addition.
        ld      bc,#%1
        add     hl,bc
} if notUsed('bc')

replace restart {
        ld      hl,#%1
        add     hl,%2
        ld      bc,#%4
        add     hl,bc
} by {
        ; peephole 43b removed loads by exploiting commutativity of addition.
        ld      hl,#%1 + %4
        add     hl,%2
} if notUsed('bc')

replace restart {
        ld      c,e
        ld      b,d
        ld      hl,#%1
        add     hl,bc
} by {
        ; peephole 43c removed loads by exploiting commutativity of addition.
        ld      hl,#%1
        add     hl,de
} if notUsed('bc')

replace restart {
        or      a,%1
        jp      NZ,%2
        xor     a,a
        or      a,%3
} by {
        or      a,%1
        jp      NZ,%2
        ; peephole 44 removed redundant zeroing of a (which has just been tested to be #0x00).
        or      a,%3
}

replace restart {
        or      a,%1
        jp      NZ,%2
        ld      %3,#0x00
} by {
        or      a,%1
        jp      NZ,%2
        ld      %3,a
        ; peephole 45 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        and     a,%1
        jp      NZ,%2
        ld      %3,#0x00
} by {
        and     a,%1
        jp      NZ,%2
        ld      %3,a
        ; peephole 46 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        sub     a,%1
        jp      NZ,%2
        ld      %3,#0x00
} by {
        sub     a,%1
        jp      NZ,%2
        ld      %3,a
        ; peephole 47 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        dec     a
        jp      NZ,%1
        ld      %2,#0x00
} by {
        dec     a
        jp      NZ,%1
        ld      %2,a
        ; peephole 48 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

//replace restart {
//      or      a,%1
//      jp      NZ,%2
//      ld      a,%3
//      or      a,a
//} by {
//      or      a,%1
//      jp      NZ,%2
//      or      a,%3
//      ; peephole 49 shortened or using a (which has just been tested to be #0x00).
//} if operandsNotSame3(%3 '(bc)' '(de)')

//replace restart {
//      and     a,%1
//      jp      NZ,%2
//      ld      a,%3
//      or      a,a
//} by {
//      and     a,%1
//      jp      NZ,%2
//      or      a,%3
//      ; peephole 50 shortened or using a (which has just been tested to be #0x00).
//} if operandsNotSame3(%3 '(bc)' '(de)')

replace restart {
        sub     a,%1
        jp      NZ,%2
        ld      a,%3
        or      a,a
} by {
        sub     a,%1
        jp      NZ,%2
        or      a,%3
        ; peephole 51 shortened or using a (which has just been tested to be #0x00).
}
//if operandsNotSame3(%3 '(bc)' '(de)')

replace restart {
        dec     a
        jp      NZ,%1
        ld      a,%2
        or      a,a
} by {
        dec     a
        jp      NZ,%1
        or      a,%2
        ; peephole 52 shortened or using a (which has just been tested to be #0x00).
}
//if operandsNotSame3(%2 '(bc)' '(de)')

replace restart {
        or      a,%1
        jp      NZ,%2
        push    %3
        ld      %4,#0x00
} by {
        or      a,%1
        jp      NZ,%2
        push    %3
        ld      %4,a
        ; peephole 53 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        and     a,%1
        jp      NZ,%2
        push    %3
        ld      %4,#0x00
} by {
        sub     a,%1
        jp      NZ,%2
        push    %3
        ld      %4,a
        ; peephole 54 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        sub     a,%1
        jp      NZ,%2
        push    %3
        ld      %4,#0x00
} by {
        sub     a,%1
        jp      NZ,%2
        push    %3
        ld      %4,a
        ; peephole 55 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        dec     a
        jp      NZ,%1
        push    %2
        ld      %3,#0x00
} by {
        dec     a
        jp      NZ,%1
        push    %2
        ld      %3,a
        ; peephole 56 replaced constant #0x00 by a (which has just been tested to be #0x00).
}

replace restart {
        ld      de,#%1 + %2
        inc     de
} by {
        ld      de,#%1 + %2+1
        ; peephole 59 moved increment of de to constant.
}

replace restart {
        ld      bc,#%1 + %2
        inc     bc
} by {
        ld      bc,#%1 + %2+1
        ; peephole 62 moved increment of bc to constant.
}

replace restart {
        ld      bc,#%1
        ld      a,c
        add     a,#0x%2
        ld      c,a
        ld      a,b
        adc     a,#0x%3
        ld      b,a
} by {
        ld      bc,#%1 + 0x%3%2
        ; peephole 63 moved addition of constant 0x%3%2 to bc to constant.
}

replace restart {
        call    %1
        ret
} by {
        jp      %1
        ; peephole 65 replaced call at end of function by jump.
}

// Callee saves ix.
replace restart {
        call    %1
        pop     ix
        ret
} by {
        pop     ix
        jp      %1
        ; peephole 66 replaced call at end of function by jump moving call beyond pop ix.
}

replace restart {
        ld      %1,a
        ld      %2,%1
        ld      %3,%1
} by {
        ; peephole 67 loaded %2, %3 from a instead of %1.
        ld      %1,a
        ld      %2,a
        ld      %3,a
} if notVolatile(%1)

replace restart {
        ld      %1,a
        ld      %2,a
        ld      %3,%1
} by {
        ld      %1,a
        ld      %2,a
        ; peephole 68 loaded %3 from a instead of %1.
        ld      %3,a
} if notVolatile(%1)

replace restart {
        ld      %1,l
        xor     a,a
        or      a,%1
} by {  
        ld      %1,l
        xor     a,a
        ; peephole 69 used l in or instead of %1.
        or      a,l
} if notVolatile(%1)

replace restart {
        ld      %1,#%2
        ld      %3,%4
        ld      %1,#%2
} by {
        ld      %1,#%2
        ld      %3,%4
        ; peephole 70 removed load of #%2 into %1 since it's still there.
} if notVolatile(%1), operandsNotRelated(%3 %1)

replace restart {
        ld      hl,#%1
        ld      de,#%1
} by {
        ; peephole 70a used #%1 from hl for load into de.
        ld      hl,#%1
        ld      e,l
        ld      d,h
}

replace restart {
        ld      hl,#%1
        push    hl
        ld      l,e
        ld      h,d
        jp      (hl)
%1:
} by {
        ; peephole 71 used ex to get de into hl.
        ex      de,hl
        ld      de,#%1
        push    de
        jp      (hl)
%1:
}
// Lets' hope this is never applied to a jump table. It's fine for calls.

// Should be after 0z.
replace restart {
        ld      %1 (ix),l
        ld      %2 (ix),h
        ld      %3,%1 (ix)
        ld      %4,%2 (ix)
} by {  
        ld      %1 (ix),l
        ld      %2 (ix),h
        ; peephole 72 used hl instead of %2 (ix), %1 (ix) to load %4%3.
        ld      %3,l
        ld      %4,h
} if operandsNotRelated('h' %3)
// Don't check for volatile since ix points to the stack.

// These ex-generating rules should be among the last ones since ex counts as a read from both hl and de for notUsed().
replace restart {
        ld      d,h
        ld      e,l
} by {
        ; peephole 73 used ex to load hl into de.
        ex      de,hl
} if notUsed('hl')

replace restart {
        ld      e,l
        ld      d,h
} by {
        ; peephole 74 used ex to load hl into de.
        ex      de,hl
} if notUsed('hl')

replace restart {
        ld      l,e
        ld      h,d
} by {
        ; peephole 75 used ex to load de into hl.
        ex      de,hl
} if notUsed('de')

// peeph-z80.def - Z80 peephole rules
//
//
// (c) Philipp Klaus Krause (pkk@spth.de, philipp@colecovision.eu) 2006 - 2007
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option) any
// later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

replace restart {
        ld      %1,#%2
        ld      a,%3 (%1)
        ld      %4,a
        ld      %1,#%5
} by {
        ld      a,(#%2 + %3)
        ; peephole z1 used #%2 directly instead of going through %1 using indirect addressing.
        ld      %4,a
        ld      %1,#%5
}

replace restart {
        ld      %1,#%2
        ld      %3 (%1),a
%4:
        ld      %1,%5
} by {
        ld      (#%2 + %3),a
        ; peephole z2 directly used #%2 instead of going through %1 using indirect addressing.
%4:
        ld      %1,%5
}

replace restart {
        pop     af
        ld      %1,#%2
        ld      %3 (%1),%4
        ld      %1,#%5
} by {
        ld      a,%4
        ld      (#%2 + %3),a
        ; peephole z3 used #%2 directly instead of going through %1 using indirect addressing.
        pop     af
        ld      %1,#%5
} if operandsNotRelated(%3 'a')

replace restart {
        ld      bc,#%1 + %2
        ld      a,%3
        ld      (bc),a
} by {
        ld      a,%3
        ld      (#%1 + %2),a
        ; peephole z4 directly used address #%1 + %2 instead of placing it in bc first.
} if notUsed('bc')

replace restart {
        ld      bc,#%1 + %2 + %6
        ld      a,%3
        ld      (bc),a
} by {
        ld      a,%3
        ld      (#%1 + %2 + %6),a
        ; peephole z5 directly used address #%1 + %2 + %6 instead of placing it in bc first.
} if notUsed('bc')

replace restart {
        ld      c,%1
        ld      l,c
        ret
} by {
        ld      l,%1
        ; peephole z8 moved %1 directly into l instead of going through c.
        ret
}

replace restart {
        ld      b,h
        ld      c,l
        pop     af
        push    bc
        call    %1
} by {
        ex      (sp),hl
        ; peephole z9 moved hl directly to the stack instead of going through bc.
        call    %1
}

replace restart {
        ld      d,h
        ld      e,l
        pop     af
        push    de
        call    %1
} by {
        ex      (sp),hl
        ; peephole z10 moved hl directly to the stack instead of going through de.
        call    %1
}

replace restart {
        jp      %5
} by {
        ret
        ; peephole z11 replaced jump by return.
} if labelIsReturnOnly(), labelRefCountChange(%5 -1)

replace restart {
        jp      %1,%5
} by {
        ret     %1
        ; peephole z11a replaced jump by return.
} if labelIsReturnOnly(), labelRefCountChange(%5 -1)

// Should be one of the last ones. Opens the code to further peephole optimization.
replace restart {
%1:
} by {
        ; peephole z12 removed unused label %1.
} if labelRefCount(%1 0)

// Applying z11 or z11a followed by z12 will often leave a dead ret at the end of the function. Remove it.
replace {
        jp      %5
        ret
} by {
        jp      %5
        ; peephole z13 removed unused ret.
}

// These two need two be here since the peephole optimizer continues to apply rules further down the file even for replace restart rules.
replace restart {
        jp      NZ,%1
        jp      %2
%1:
} by {
        jp      Z,%2
        ; peephole 5' removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

replace restart {
        jp      Z,%1
        jp      %2
%1:
} by {
        jp      NZ,%2
        ; peephole 6' removed jp by using inverse jump logic
%1:
} if labelRefCountChange(%1 -1)

// These should be the last rules, so that the peepholes above need to look at jp only.
replace {
        jp      %5
} by {
        jr      %5
        ; peephole z14 changed absolute to relative unconditional jump.
} if labelInRange()

replace {
        jp      Z,%5
} by {
        jr      Z,%5
        ; peephole z15 changed absolute to relative conditional jump.
} if labelInRange()

replace {
        jp      NZ,%5
} by {
        jr      NZ,%5
        ; peephole z16 changed absolute to relative conditional jump.
} if labelInRange()

replace {
        jp      C,%5
} by {
        jr      C,%5
        ; peephole z17 changed absolute to relative conditional jump.
} if labelInRange()

replace {
        jp      NC,%5
} by {
        jr      NC,%5
        ; peephole z18 changed absolute to relative conditional jump.
} if labelInRange()