Yet another optimized bug - Printable Version

Yet another optimized bug - Printable Version

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Yet another optimized bug - einar - 12-17-2015

Sample program test.bas:

Code:
GOTO 10 

sub FASTCALL proc1()

    asm

start:

        ld hl,(stuff)

        ld (23672),hl

        ret

stuff:

        defw 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

        defw 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

        defw 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

        defw 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

    end asm

end sub

sub FASTCALL proc2(a AS UBYTE)

    asm

        cp      10

        jr      nz, skip

        dec     a

skip:

        jp      start

    end asm

end sub

10 proc1()

   proc2(0)

Compiling it using -O2 works correctly and produces the following code for routine proc2:

Code:
_proc2:

#line 17

        cp      10

        jr      nz, skip

        dec     a

skip:

        jp      start

#line 22

_proc2__leave:

        ret

Compiling it using -O3 produces error "Relative jump out of range" and produces the following code for routine proc2:

Code:
_proc2:

#line 17

        cp      10

        jr      nz, start

        dec     a

skip:

        jp      start

#line 22

_proc2__leave:

        ret

Again, the optimizer is supposed to try to optimize its own generated code only, not someone else's assembly code!