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

// peeph.def - Common Z80 and gbz80 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,%1
} by {
        ; peephole 1 removed redundant load.
} if notVolatile(%1)

replace restart {
        ld      %1,%3
        ld      %1,%2
} by {
        ; peephole 2 removed dead load into %1
        ld      %1,%2
} if notVolatile(%1 %3), operandsNotSame

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 {
        ld      %2,%3
        jp      %4
%5:
        ld      %2,%3
%4:
} by {
        ; peephole 9 removed jump and redundant load.
%5:
        ld      %2,%3
%4:
} if labelRefCountChange(%4 -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      %2,%3
        ld      a,%2
        and     a,%1
        ld      %2,%4
} by {
        ld      a,%3
        ; peephole 16 moved %3 directly into a instead of going through %2.
        and     a,%1
        ld      %2,%4
} if notVolatile(%2), operandsNotSame

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 {
        and     a,%1
        or      a,a
} by {
        and     a,%1
        ; peephole 20 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 {
        ld      %1,a
        and     a,%2
        ld      %1,a
} by {
        ; peephole 22 removed redundant load into %1.
        and     a,%2
        ld      %1,a
} if notVolatile(%1)

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      b,%1
        ld      a,b
        pop     bc
} by {
        ld      a,%1
        ; peephole 25 removed load into b
        pop     bc
}

replace restart {
        ld      c,%1
        ld      a,c
        pop     bc
} by {
        ld      a,%1
        ; peephole 26 removed load into c
        pop     bc
}

replace restart {
        ld      d,%1
        ld      a,d
        pop     de
} by {
        ld      a,%1
        ; peephole 27 removed load into d
        pop     de
}

replace restart {
        ld      e,%1
        ld      a,e
        pop     de
} by {
        ld      a,%1
        ; peephole 28 removed load into e
        pop     de
}

replace restart {
        ld      h,%1
        ld      a,h
        pop     hl
} by {
        ld      a,%1
        ; peephole 29 removed load into h
        pop     hl
}

replace restart {
        ld      l,%1
        ld      a,l
        pop     hl
} by {
        ld      a,%1
        ; peephole 30 removed load into l
        pop     hl
}

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
        ld      %1,a
} by {
        ; peephole 42 removed loads by exploiting commutativity of addition.
        add     a,%2
        ld      %1,a
} if notVolatile(%1)

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
}

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).
}

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).
}

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).
}

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).
}

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
        inc     de
        inc     de
} by {
        ld      de,#%1 + %2 + 3
        ; peephole 57 moved triple increment of de to constant.
}

replace restart {
        ld      de,#%1 + %2
        inc     de
        inc     de
} by {
        ld      de,#%1 + %2 + 2
        ; peephole 58 moved double increment of de to constant.
}

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
        inc     bc
        inc     bc
} by {
        ld      bc,#%1 + %2 + 3
        ; peephole 60 moved triple increment of bc to constant.
}

replace restart {
        ld      bc,#%1 + %2
        inc     bc
        inc     bc
} by {
        ld      bc,#%1 + %2 + 2
        ; peephole 61 moved double increment of bc 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 {
        ld      bc,#%1 + %4
        ld      a,c
        add     a,#0x%2
        ld      c,a
        ld      a,b
        adc     a,#0x%3
        ld      b,a
} by {
        ld      bc,#%1 + %4 + 0x%3%2
        ; peephole 64 moved addition of constant 0x%3%2 to bc to constant.
}