#441 [z80] disallowed undocumented instructions

[Job Bolle]

Peephole rule 174b (and possibly others?) can generate iyl/iyh instructions when not allowed.
This is because the canSplitReg() restriction splits iy into iyl/iyh.

This problem goes away by testing for HAS_IYL_INST instead of !IS_SM83 in z80canSplitReg()

--- a/src/z80/peep.c
+++ b/src/z80/peep.c
@@ -1294,7 +1294,7 @@ bool z80canSplitReg (const char *reg, char dst[][16], int nDst)
           dst[i][1] = '\0';
         }
     }
-  else if (!IS_SM83 && (!strcmp (reg, "ix") || !strcmp (reg, "iy")))
+  else if (HAS_IYL_INST && (!strcmp (reg, "ix") || !strcmp (reg, "iy")))
     {
       for (i = 0; i < nDst; ++i)
         {

[Job Bolle]

Example to reproduce:

sdcc -mz80 --max-allocs-per-node 50000 -c device/lib/_fsadd.c
_fsadd.asm:512: Error: <a> Invalid Addressing Mode.
_fsadd.asm:513: Error: <a> Invalid Addressing Mode.
removing _fsadd.rel

509:        jr  00142$
510:    00141$:
511:        ld  bc, #0x0000
512:        ld  iyh, b
513:        ld  iyl, c
514:    00142$:
515:        ld  e, -9 (ix)
516:        ld  a, -8 (ix)

[Job Bolle]

... additionally, this replacement is not an optimization:

ld  iy, #0x0000  ; 4B, 14T

ld  iyh, b       ; 2B,  8T
ld  iyl, c       ; 2B,  8T

It is not smaller, and it takes 2 more cycles.

[Philipp Klaus Krause]

These issues should be fixed in [r13742].

[Job Bolle]

peep rule 174a now has the notSame(%1 'ix' 'iy') and notSame(%2 'ix' 'iy') restrictions twice.

[Philipp Klaus Krause]

Thanks. Fixed in [r13744].