1 /** @name Z80 Register allocation functions.
4 Note: much of this is ripped straight from Sandeep's mcs51 code.
6 This code maps the virtual symbols and code onto the real
7 hardware. It allocates based on usage and how long the varible
8 lives into registers or temporary memory on the stack.
10 On the Z80 hl and ix and a are reserved for the code generator,
11 leaving bc and de for allocation. iy is unusable due to currently
12 as it's only adressable as a pair. The extra register pressure
13 from reserving hl is made up for by how much easier the sub
14 operations become. You could swap hl for iy if the undocumented
15 iyl/iyh instructions are available.
17 The stack frame is the common ix-bp style. Basically:
22 ix+0: calling functions ix
25 sp: end of local varibles
27 There is currently no support for bit spaces or banked functions.
29 This program is free software; you can redistribute it and/or
30 modify it under the terms of the GNU General Public License as
31 published by the Free Software Foundation; either version 2, or (at
32 your option) any later version. This program is distributed in the
33 hope that it will be useful, but WITHOUT ANY WARRANTY; without even
34 the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
35 PURPOSE. See the GNU General Public License for more details.
37 You should have received a copy of the GNU General Public License
38 along with this program; if not, write to the Free Software
39 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
40 USA. In other words, you are welcome to use, share and improve
41 this program. You are forbidden to forbid anyone else to use,
42 share and improve what you give them. Help stamp out
48 /* Flags to turn off optimisations.
53 DISABLE_PACK_ASSIGN = 0,
54 /* Pack for one use is quite broken. */
55 DISABLE_PACK_ONE_USE = 1,
59 /* Flags to turn on debugging code.
66 D_ACCUSE2_VERBOSE = 0,
71 #define D(_a, _s) if (_a) { printf _s; fflush(stdout); }
76 #define DISABLE_PACKREGSFORSUPPORT 1
77 #define DISABLE_PACKREGSFORACCUSE 1
79 extern void genZ80Code (iCode *);
81 /** Local static variables */
89 /* registers used in a function */
96 static regs _gbz80_regs[] =
98 {REG_GPR, C_IDX, "c", 1},
99 {REG_GPR, B_IDX, "b", 1},
100 {REG_CND, CND_IDX, "c", 1}
103 static regs _z80_regs[] =
105 {REG_GPR, C_IDX, "c", 1},
106 {REG_GPR, B_IDX, "b", 1},
107 {REG_GPR, E_IDX, "e", 1},
108 {REG_GPR, D_IDX, "d", 1},
109 {REG_CND, CND_IDX, "c", 1}
114 /** Number of usable registers (all but C) */
115 #define Z80_MAX_REGS ((sizeof(_z80_regs)/sizeof(_z80_regs[0]))-1)
116 #define GBZ80_MAX_REGS ((sizeof(_gbz80_regs)/sizeof(_gbz80_regs[0]))-1)
118 static void spillThis (symbol *);
120 /** Allocates register of given type.
121 'type' is not used on the z80 version. It was used to select
122 between pointer and general purpose registers on the mcs51 version.
124 @return Pointer to the newly allocated register.
127 allocReg (short type)
131 for (i = 0; i < _G.nRegs; i++)
133 /* For now we allocate from any free */
134 if (regsZ80[i].isFree)
136 regsZ80[i].isFree = 0;
139 currFunc->regsUsed = bitVectSetBit (currFunc->regsUsed, i);
141 D (D_ALLOC, ("allocReg: alloced %p\n", ®sZ80[i]));
145 D (D_ALLOC, ("allocReg: No free.\n"));
149 /** Returns pointer to register wit index number
156 for (i = 0; i < _G.nRegs; i++)
158 if (regsZ80[i].rIdx == idx)
164 wassertl (0, "regWithIdx not found");
168 /** Frees a register.
173 wassert (!reg->isFree);
175 D (D_ALLOC, ("freeReg: freed %p\n", reg));
179 /** Returns number of free registers.
187 for (i = 0; i < _G.nRegs; i++)
189 /* For now only one reg type */
190 if (regsZ80[i].isFree)
198 /** Free registers with type.
201 nfreeRegsType (int type)
206 if ((nfr = nFreeRegs (type)) == 0)
208 return nFreeRegs (REG_GPR);
212 return nFreeRegs (type);
217 /*-----------------------------------------------------------------*/
218 /* allDefsOutOfRange - all definitions are out of a range */
219 /*-----------------------------------------------------------------*/
221 allDefsOutOfRange (bitVect * defs, int fseq, int toseq)
228 for (i = 0; i < defs->size; i++)
232 if (bitVectBitValue (defs, i) &&
233 (ic = hTabItemWithKey (iCodehTab, i)) &&
234 (ic->seq >= fseq && ic->seq <= toseq))
244 /*-----------------------------------------------------------------*/
245 /* computeSpillable - given a point find the spillable live ranges */
246 /*-----------------------------------------------------------------*/
248 computeSpillable (iCode * ic)
252 /* spillable live ranges are those that are live at this
253 point . the following categories need to be subtracted
255 a) - those that are already spilt
256 b) - if being used by this one
257 c) - defined by this one */
259 spillable = bitVectCopy (ic->rlive);
261 bitVectCplAnd (spillable, _G.spiltSet); /* those already spilt */
263 bitVectCplAnd (spillable, ic->uses); /* used in this one */
264 bitVectUnSetBit (spillable, ic->defKey);
265 spillable = bitVectIntersect (spillable, _G.regAssigned);
270 /*-----------------------------------------------------------------*/
271 /* noSpilLoc - return true if a variable has no spil location */
272 /*-----------------------------------------------------------------*/
274 noSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
276 return (sym->usl.spillLoc ? 0 : 1);
279 /*-----------------------------------------------------------------*/
280 /* hasSpilLoc - will return 1 if the symbol has spil location */
281 /*-----------------------------------------------------------------*/
283 hasSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
285 return (sym->usl.spillLoc ? 1 : 0);
288 /** Will return 1 if the remat flag is set.
289 A symbol is rematerialisable if it doesnt need to be allocated
290 into registers at creation as it can be re-created at any time -
291 i.e. it's constant in some way.
294 rematable (symbol * sym, eBBlock * ebp, iCode * ic)
299 /*-----------------------------------------------------------------*/
300 /* allLRs - return true for all */
301 /*-----------------------------------------------------------------*/
303 allLRs (symbol * sym, eBBlock * ebp, iCode * ic)
308 /** liveRangesWith - applies function to a given set of live range
311 liveRangesWith (bitVect * lrs, int (func) (symbol *, eBBlock *, iCode *),
312 eBBlock * ebp, iCode * ic)
317 if (!lrs || !lrs->size)
320 for (i = 1; i < lrs->size; i++)
323 if (!bitVectBitValue (lrs, i))
326 /* if we don't find it in the live range
327 hash table we are in serious trouble */
328 if (!(sym = hTabItemWithKey (liveRanges, i)))
330 wassertl (0, "liveRangesWith could not find liveRange");
334 if (func (sym, ebp, ic) && bitVectBitValue (_G.regAssigned, sym->key))
336 addSetHead (&rset, sym);
344 /** leastUsedLR - given a set determines which is the least used
347 leastUsedLR (set * sset)
349 symbol *sym = NULL, *lsym = NULL;
351 sym = lsym = setFirstItem (sset);
356 for (; lsym; lsym = setNextItem (sset))
359 /* if usage is the same then prefer
360 the spill the smaller of the two */
361 if (lsym->used == sym->used)
362 if (getSize (lsym->type) < getSize (sym->type))
366 if (lsym->used < sym->used)
371 setToNull ((void **) &sset);
376 /** noOverLap - will iterate through the list looking for over lap
379 noOverLap (set * itmpStack, symbol * fsym)
383 for (sym = setFirstItem (itmpStack); sym;
384 sym = setNextItem (itmpStack))
386 // if sym starts before (or on) our end point
387 // and ends after (or on) our start point,
389 if (sym->liveFrom <= fsym->liveTo &&
390 sym->liveTo >= fsym->liveFrom)
398 /*-----------------------------------------------------------------*/
399 /* isFree - will return 1 if the a free spil location is found */
400 /*-----------------------------------------------------------------*/
404 V_ARG (symbol **, sloc);
405 V_ARG (symbol *, fsym);
407 /* if already found */
411 /* if it is free && and the itmp assigned to
412 this does not have any overlapping live ranges
413 with the one currently being assigned and
414 the size can be accomodated */
416 noOverLap (sym->usl.itmpStack, fsym) &&
417 getSize (sym->type) >= getSize (fsym->type))
426 /*-----------------------------------------------------------------*/
427 /* createStackSpil - create a location on the stack to spil */
428 /*-----------------------------------------------------------------*/
430 createStackSpil (symbol * sym)
434 D (D_ALLOC, ("createStackSpil: for sym %p\n", sym));
436 /* first go try and find a free one that is already
437 existing on the stack */
438 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
440 /* found a free one : just update & return */
441 sym->usl.spillLoc = sloc;
444 addSetHead (&sloc->usl.itmpStack, sym);
445 D (D_ALLOC, ("createStackSpil: found existing\n"));
449 /* could not then have to create one , this is the hard part
450 we need to allocate this on the stack : this is really a
451 hack!! but cannot think of anything better at this time */
453 sprintf (buffer, "sloc%d", _G.slocNum++);
454 sloc = newiTemp (buffer);
456 /* set the type to the spilling symbol */
457 sloc->type = copyLinkChain (sym->type);
458 sloc->etype = getSpec (sloc->type);
459 SPEC_SCLS (sloc->etype) = S_AUTO;
460 SPEC_STAT (sloc->etype) = 0;
464 sloc->isref = 1; /* to prevent compiler warning */
466 /* if it is on the stack then update the stack */
467 if (IN_STACK (sloc->etype))
469 currFunc->stack += getSize (sloc->type);
470 _G.stackExtend += getSize (sloc->type);
474 _G.dataExtend += getSize (sloc->type);
477 /* add it to the stackSpil set */
478 addSetHead (&_G.stackSpil, sloc);
479 sym->usl.spillLoc = sloc;
482 /* add it to the set of itempStack set
483 of the spill location */
484 addSetHead (&sloc->usl.itmpStack, sym);
486 D (D_ALLOC, ("createStackSpil: created new\n"));
490 /*-----------------------------------------------------------------*/
491 /* spillThis - spils a specific operand */
492 /*-----------------------------------------------------------------*/
494 spillThis (symbol * sym)
498 D (D_ALLOC, ("spillThis: spilling %p\n", sym));
500 /* if this is rematerializable or has a spillLocation
501 we are okay, else we need to create a spillLocation
503 if (!(sym->remat || sym->usl.spillLoc))
505 createStackSpil (sym);
508 /* mark it has spilt & put it in the spilt set */
510 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
512 bitVectUnSetBit (_G.regAssigned, sym->key);
514 for (i = 0; i < sym->nRegs; i++)
518 freeReg (sym->regs[i]);
523 if (sym->usl.spillLoc && !sym->remat)
525 sym->usl.spillLoc->allocreq = 1;
531 /*-----------------------------------------------------------------*/
532 /* allDefsOutOfRange - all definitions are out of a range */
533 /*-----------------------------------------------------------------*/
535 allDefsOutOfRange (bitVect * defs, int fseq, int toseq)
542 for (i = 0; i < defs->size; i++)
546 if (bitVectBitValue (defs, i) &&
547 (ic = hTabItemWithKey (iCodehTab, i)) &&
548 (ic->seq >= fseq && ic->seq <= toseq))
557 /*-----------------------------------------------------------------*/
558 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location */
559 /* but is not used as a pointer */
560 /*-----------------------------------------------------------------*/
562 hasSpilLocnoUptr (symbol * sym, eBBlock * ebp, iCode * ic)
564 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
567 /*-----------------------------------------------------------------*/
568 /* notUsedInBlock - not used in this block */
569 /*-----------------------------------------------------------------*/
571 notUsedInBlock (symbol * sym, eBBlock * ebp, iCode * ic)
573 return (!bitVectBitsInCommon (sym->defs, ebp->usesDefs) &&
574 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
575 /* return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs)); */
578 /*-----------------------------------------------------------------*/
579 /* notUsedInRemaining - not used or defined in remain of the block */
580 /*-----------------------------------------------------------------*/
582 notUsedInRemaining (symbol * sym, eBBlock * ebp, iCode * ic)
584 return ((usedInRemaining (operandFromSymbol (sym), ic) ? 0 : 1) &&
585 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
589 /** Select a iTemp to spil : rather a simple procedure.
592 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
594 bitVect *lrcs = NULL;
598 D (D_ALLOC, ("selectSpil: finding spill for ic %p\n", ic));
599 /* get the spillable live ranges */
600 lrcs = computeSpillable (ic);
602 /* get all live ranges that are rematerizable */
603 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
605 D (D_ALLOC, ("selectSpil: using remat.\n"));
606 /* return the least used of these */
607 return leastUsedLR (selectS);
611 /* get live ranges with spillLocations in direct space */
612 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
614 sym = leastUsedLR (selectS);
615 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
616 sym->usl.spillLoc->rname :
617 sym->usl.spillLoc->name));
619 /* mark it as allocation required */
620 sym->usl.spillLoc->allocreq = 1;
624 /* if the symbol is local to the block then */
625 if (forSym->liveTo < ebp->lSeq)
628 /* check if there are any live ranges allocated
629 to registers that are not used in this block */
630 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
632 sym = leastUsedLR (selectS);
633 /* if this is not rematerializable */
637 wassertl (0, "Attempted to do an unsupported block spill");
643 /* check if there are any live ranges that not
644 used in the remainder of the block */
645 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
647 sym = leastUsedLR (selectS);
652 wassertl (0, "Attempted to do an unsupported remain spill");
660 /* find live ranges with spillocation && not used as pointers */
661 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
664 sym = leastUsedLR (selectS);
665 /* mark this as allocation required */
666 sym->usl.spillLoc->allocreq = 1;
671 /* find live ranges with spillocation */
672 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
674 D (D_ALLOC, ("selectSpil: using with spill.\n"));
675 sym = leastUsedLR (selectS);
676 sym->usl.spillLoc->allocreq = 1;
680 /* couldn't find then we need to create a spil
681 location on the stack , for which one? the least
683 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
685 D (D_ALLOC, ("selectSpil: creating new spill.\n"));
686 /* return a created spil location */
687 sym = createStackSpil (leastUsedLR (selectS));
688 sym->usl.spillLoc->allocreq = 1;
692 /* this is an extreme situation we will spill
693 this one : happens very rarely but it does happen */
694 D (D_ALLOC, ("selectSpil: using spillThis.\n"));
700 /** Spil some variable & mark registers as free.
701 A spill occurs when an iTemp wont fit into the available registers.
704 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
709 D (D_ALLOC, ("spilSomething: spilling on ic %p\n", ic));
711 /* get something we can spil */
712 ssym = selectSpil (ic, ebp, forSym);
714 /* mark it as spilt */
716 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
718 /* mark it as not register assigned &
719 take it away from the set */
720 bitVectUnSetBit (_G.regAssigned, ssym->key);
722 /* mark the registers as free */
723 for (i = 0; i < ssym->nRegs; i++)
725 freeReg (ssym->regs[i]);
727 wassertl (ssym->blockSpil == 0, "Encountered a sym with a block spill");
728 wassertl (ssym->remainSpil == 0, "Encountered a sym with a remain spill");
730 /* if spilt on stack then free up r0 & r1
731 if they could have been assigned to as gprs */
732 if (!ptrRegReq && isSpiltOnStack (ssym))
735 spillLRWithPtrReg (ssym);
738 /* if this was a block level spil then insert push & pop
739 at the start & end of block respectively */
742 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
743 /* add push to the start of the block */
744 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
745 ebp->sch->next : ebp->sch));
746 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
747 /* add pop to the end of the block */
748 addiCodeToeBBlock (ebp, nic, NULL);
751 /* if spilt because not used in the remainder of the
752 block then add a push before this instruction and
753 a pop at the end of the block */
754 if (ssym->remainSpil)
757 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
758 /* add push just before this instruction */
759 addiCodeToeBBlock (ebp, nic, ic);
761 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
762 /* add pop to the end of the block */
763 addiCodeToeBBlock (ebp, nic, NULL);
767 D (D_ALLOC, ("spilSomething: done.\n"));
775 /** Will try for GPR if not spil.
778 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
782 D (D_ALLOC, ("getRegGpr: on ic %p\n", ic));
784 /* try for gpr type */
785 if ((reg = allocReg (REG_GPR)))
787 D (D_ALLOC, ("getRegGpr: got a reg.\n"));
791 /* we have to spil */
792 if (!spilSomething (ic, ebp, sym))
794 D (D_ALLOC, ("getRegGpr: have to spill.\n"));
798 /* this looks like an infinite loop but
799 in really selectSpil will abort */
803 /** Symbol has a given register.
806 symHasReg (symbol * sym, regs * reg)
810 for (i = 0; i < sym->nRegs; i++)
811 if (sym->regs[i] == reg)
817 /** Check the live to and if they have registers & are not spilt then
818 free up the registers
821 deassignLRs (iCode * ic, eBBlock * ebp)
827 for (sym = hTabFirstItem (liveRanges, &k); sym;
828 sym = hTabNextItem (liveRanges, &k))
832 /* if it does not end here */
833 if (sym->liveTo > ic->seq)
836 /* if it was spilt on stack then we can
837 mark the stack spil location as free */
842 sym->usl.spillLoc->isFree = 1;
848 if (!bitVectBitValue (_G.regAssigned, sym->key))
851 /* special case check if this is an IFX &
852 the privious one was a pop and the
853 previous one was not spilt then keep track
855 if (ic->op == IFX && ic->prev &&
856 ic->prev->op == IPOP &&
857 !ic->prev->parmPush &&
858 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
859 psym = OP_SYMBOL (IC_LEFT (ic->prev));
861 D (D_ALLOC, ("deassignLRs: in loop on sym %p nregs %u\n", sym, sym->nRegs));
867 bitVectUnSetBit (_G.regAssigned, sym->key);
869 /* if the result of this one needs registers
870 and does not have it then assign it right
872 if (IC_RESULT (ic) &&
873 !(SKIP_IC2 (ic) || /* not a special icode */
874 ic->op == JUMPTABLE ||
879 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
880 result->liveTo > ic->seq && /* and will live beyond this */
881 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
882 result->regType == sym->regType && /* same register types */
883 result->nRegs && /* which needs registers */
884 !result->isspilt && /* and does not already have them */
886 !bitVectBitValue (_G.regAssigned, result->key) &&
887 /* the number of free regs + number of regs in this LR
888 can accomodate the what result Needs */
889 ((nfreeRegsType (result->regType) +
890 sym->nRegs) >= result->nRegs)
893 for (i = 0; i < result->nRegs; i++)
896 result->regs[i] = sym->regs[i];
898 result->regs[i] = getRegGpr (ic, ebp, result);
900 /* if the allocation falied which means
901 this was spilt then break */
902 if (!result->regs[i])
910 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
913 /* free the remaining */
914 for (; i < sym->nRegs; i++)
918 if (!symHasReg (psym, sym->regs[i]))
919 freeReg (sym->regs[i]);
922 freeReg (sym->regs[i]);
923 // sym->regs[i] = NULL;
930 /** Reassign this to registers.
933 reassignLR (operand * op)
935 symbol *sym = OP_SYMBOL (op);
938 D (D_ALLOC, ("reassingLR: on sym %p\n", sym));
940 /* not spilt any more */
941 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
942 bitVectUnSetBit (_G.spiltSet, sym->key);
944 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
948 for (i = 0; i < sym->nRegs; i++)
949 sym->regs[i]->isFree = 0;
952 /** Determines if allocating will cause a spill.
955 willCauseSpill (int nr, int rt)
957 /* first check if there are any avlb registers
958 of te type required */
959 if (nFreeRegs (0) >= nr)
962 /* it will cause a spil */
966 /** The allocator can allocate same registers to result and operand,
967 if this happens make sure they are in the same position as the operand
968 otherwise chaos results.
971 positionRegs (symbol * result, symbol * opsym, int lineno)
973 int count = min (result->nRegs, opsym->nRegs);
974 int i, j = 0, shared = 0;
976 D (D_ALLOC, ("positionRegs: on result %p opsum %p line %u\n", result, opsym, lineno));
978 /* if the result has been spilt then cannot share */
983 /* first make sure that they actually share */
984 for (i = 0; i < count; i++)
986 for (j = 0; j < count; j++)
988 if (result->regs[i] == opsym->regs[j] && i != j)
998 regs *tmp = result->regs[i];
999 result->regs[i] = result->regs[j];
1000 result->regs[j] = tmp;
1005 /** Try to allocate a pair of registers to the symbol.
1008 tryAllocatingRegPair (symbol * sym)
1011 wassert (sym->nRegs == 2);
1012 for (i = 0; i < _G.nRegs; i += 2)
1014 if ((regsZ80[i].isFree) && (regsZ80[i + 1].isFree))
1016 regsZ80[i].isFree = 0;
1017 sym->regs[0] = ®sZ80[i];
1018 regsZ80[i + 1].isFree = 0;
1019 sym->regs[1] = ®sZ80[i + 1];
1022 currFunc->regsUsed =
1023 bitVectSetBit (currFunc->regsUsed, i);
1024 currFunc->regsUsed =
1025 bitVectSetBit (currFunc->regsUsed, i + 1);
1027 D (D_ALLOC, ("tryAllocRegPair: succeded for sym %p\n", sym));
1031 D (D_ALLOC, ("tryAllocRegPair: failed on sym %p\n", sym));
1035 /** Serially allocate registers to the variables.
1036 This is the main register allocation function. It is called after
1040 serialRegAssign (eBBlock ** ebbs, int count)
1044 /* for all blocks */
1045 for (i = 0; i < count; i++)
1050 if (ebbs[i]->noPath &&
1051 (ebbs[i]->entryLabel != entryLabel &&
1052 ebbs[i]->entryLabel != returnLabel))
1055 /* of all instructions do */
1056 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1059 /* if this is an ipop that means some live
1060 range will have to be assigned again */
1064 reassignLR (IC_LEFT (ic));
1067 /* if result is present && is a true symbol */
1068 if (IC_RESULT (ic) && ic->op != IFX &&
1069 IS_TRUE_SYMOP (IC_RESULT (ic)))
1070 OP_SYMBOL (IC_RESULT (ic))->allocreq = 1;
1072 /* take away registers from live
1073 ranges that end at this instruction */
1074 deassignLRs (ic, ebbs[i]);
1076 /* some don't need registers */
1077 /* MLH: removed RESULT and POINTER_SET condition */
1078 if (SKIP_IC2 (ic) ||
1079 ic->op == JUMPTABLE ||
1085 /* now we need to allocate registers only for the result */
1088 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1093 D (D_ALLOC, ("serialRegAssign: in loop on result %p\n", sym));
1095 /* if it does not need or is spilt
1096 or is already assigned to registers
1097 or will not live beyond this instructions */
1100 bitVectBitValue (_G.regAssigned, sym->key) ||
1101 sym->liveTo <= ic->seq)
1103 D (D_ALLOC, ("serialRegAssign: wont live long enough.\n"));
1107 /* if some liverange has been spilt at the block level
1108 and this one live beyond this block then spil this
1110 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq)
1112 D (D_ALLOC, ("serialRegAssign: \"spilling to be safe.\"\n"));
1116 /* if trying to allocate this will cause
1117 a spill and there is nothing to spill
1118 or this one is rematerializable then
1120 willCS = willCauseSpill (sym->nRegs, sym->regType);
1121 spillable = computeSpillable (ic);
1123 (willCS && bitVectIsZero (spillable)))
1126 D (D_ALLOC, ("serialRegAssign: \"remat spill\"\n"));
1132 /* if it has a spillocation & is used less than
1133 all other live ranges then spill this */
1135 if (sym->usl.spillLoc) {
1136 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1137 allLRs, ebbs[i], ic));
1138 if (leastUsed && leastUsed->used > sym->used) {
1143 /* if none of the liveRanges have a spillLocation then better
1144 to spill this one than anything else already assigned to registers */
1145 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1152 /* else we assign registers to it */
1153 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1155 /* Special case: Try to fit into a reg pair if
1157 D (D_ALLOC, ("serialRegAssign: actually allocing regs!\n"));
1158 if ((sym->nRegs == 2) && tryAllocatingRegPair (sym))
1163 for (j = 0; j < sym->nRegs; j++)
1165 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1167 /* if the allocation falied which means
1168 this was spilt then break */
1171 D (D_ALLOC, ("Couldnt alloc (spill)\n"))
1176 /* if it shares registers with operands make sure
1177 that they are in the same position */
1178 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1179 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=')
1180 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1181 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1182 /* do the same for the right operand */
1183 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1184 OP_SYMBOL (IC_RIGHT (ic))->nRegs)
1185 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1186 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1193 /*-----------------------------------------------------------------*/
1194 /* rUmaskForOp :- returns register mask for an operand */
1195 /*-----------------------------------------------------------------*/
1197 rUmaskForOp (operand * op)
1203 /* only temporaries are assigned registers */
1207 sym = OP_SYMBOL (op);
1209 /* if spilt or no registers assigned to it
1211 if (sym->isspilt || !sym->nRegs)
1214 rumask = newBitVect (_G.nRegs);
1216 for (j = 0; j < sym->nRegs; j++)
1218 rumask = bitVectSetBit (rumask, sym->regs[j]->rIdx);
1225 z80_rUmaskForOp (operand * op)
1227 return rUmaskForOp (op);
1230 /** Returns bit vector of registers used in iCode.
1233 regsUsedIniCode (iCode * ic)
1235 bitVect *rmask = newBitVect (_G.nRegs);
1237 /* do the special cases first */
1240 rmask = bitVectUnion (rmask,
1241 rUmaskForOp (IC_COND (ic)));
1245 /* for the jumptable */
1246 if (ic->op == JUMPTABLE)
1248 rmask = bitVectUnion (rmask,
1249 rUmaskForOp (IC_JTCOND (ic)));
1254 /* of all other cases */
1256 rmask = bitVectUnion (rmask,
1257 rUmaskForOp (IC_LEFT (ic)));
1261 rmask = bitVectUnion (rmask,
1262 rUmaskForOp (IC_RIGHT (ic)));
1265 rmask = bitVectUnion (rmask,
1266 rUmaskForOp (IC_RESULT (ic)));
1272 /** For each instruction will determine the regsUsed.
1275 createRegMask (eBBlock ** ebbs, int count)
1279 /* for all blocks */
1280 for (i = 0; i < count; i++)
1284 if (ebbs[i]->noPath &&
1285 (ebbs[i]->entryLabel != entryLabel &&
1286 ebbs[i]->entryLabel != returnLabel))
1289 /* for all instructions */
1290 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1295 if (SKIP_IC2 (ic) || !ic->rlive)
1298 /* first mark the registers used in this
1300 ic->rUsed = regsUsedIniCode (ic);
1301 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1303 /* now create the register mask for those
1304 registers that are in use : this is a
1305 super set of ic->rUsed */
1306 ic->rMask = newBitVect (_G.nRegs + 1);
1308 /* for all live Ranges alive at this point */
1309 for (j = 1; j < ic->rlive->size; j++)
1314 /* if not alive then continue */
1315 if (!bitVectBitValue (ic->rlive, j))
1318 /* find the live range we are interested in */
1319 if (!(sym = hTabItemWithKey (liveRanges, j)))
1321 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1322 "createRegMask cannot find live range");
1326 /* if no register assigned to it */
1327 if (!sym->nRegs || sym->isspilt)
1330 /* for all the registers allocated to it */
1331 for (k = 0; k < sym->nRegs; k++)
1334 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1340 /** Returns the rematerialized string for a remat var.
1343 rematStr (symbol * sym)
1346 iCode *ic = sym->rematiCode;
1351 /* if plus or minus print the right hand side */
1352 if (ic->op == '+' || ic->op == '-')
1354 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1357 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1360 /* we reached the end */
1361 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1368 /*-----------------------------------------------------------------*/
1369 /* regTypeNum - computes the type & number of registers required */
1370 /*-----------------------------------------------------------------*/
1377 /* for each live range do */
1378 for (sym = hTabFirstItem (liveRanges, &k); sym;
1379 sym = hTabNextItem (liveRanges, &k))
1382 /* if used zero times then no registers needed */
1383 if ((sym->liveTo - sym->liveFrom) == 0)
1386 D (D_ALLOC, ("regTypeNum: loop on sym %p\n", sym));
1388 /* if the live range is a temporary */
1392 /* if the type is marked as a conditional */
1393 if (sym->regType == REG_CND)
1396 /* if used in return only then we don't
1398 if (sym->ruonly || sym->accuse)
1400 if (IS_AGGREGATE (sym->type) || sym->isptr)
1401 sym->type = aggrToPtr (sym->type, FALSE);
1405 /* if not then we require registers */
1406 D (D_ALLOC, ("regTypeNum: isagg %u nRegs %u type %p\n", IS_AGGREGATE (sym->type) || sym->isptr, sym->nRegs, sym->type));
1407 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1408 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1409 getSize (sym->type));
1410 D (D_ALLOC, ("regTypeNum: setting nRegs of %s (%p) to %u\n", sym->name, sym, sym->nRegs));
1412 D (D_ALLOC, ("regTypeNum: setup to assign regs sym %p\n", sym));
1416 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1417 printTypeChain (sym->type, stderr);
1418 fprintf (stderr, "\n");
1421 /* determine the type of register required */
1422 /* Always general purpose */
1423 sym->regType = REG_GPR;
1428 /* for the first run we don't provide */
1429 /* registers for true symbols we will */
1430 /* see how things go */
1431 D (D_ALLOC, ("regTypeNum: #2 setting num of %p to 0\n", sym));
1438 /** Mark all registers as free.
1445 D (D_ALLOC, ("freeAllRegs: running.\n"));
1447 for (i = 0; i < _G.nRegs; i++)
1448 regsZ80[i].isFree = 1;
1451 /*-----------------------------------------------------------------*/
1452 /* deallocStackSpil - this will set the stack pointer back */
1453 /*-----------------------------------------------------------------*/
1454 DEFSETFUNC (deallocStackSpil)
1462 /** Register reduction for assignment.
1465 packRegsForAssign (iCode * ic, eBBlock * ebp)
1469 D (D_ALLOC, ("packRegsForAssign: running on ic %p\n", ic));
1471 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1472 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1473 OP_LIVETO (IC_RIGHT (ic)) > ic->seq)
1479 /* if the true symbol is defined in far space or on stack
1480 then we should not since this will increase register pressure */
1481 if (isOperandInFarSpace (IC_RESULT (ic)))
1483 if ((dic = farSpacePackable (ic)))
1490 /* find the definition of iTempNN scanning backwards if we find a
1491 a use of the true symbol in before we find the definition then
1493 for (dic = ic->prev; dic; dic = dic->prev)
1495 /* if there is a function call and this is
1496 a parameter & not my parameter then don't pack it */
1497 if ((dic->op == CALL || dic->op == PCALL) &&
1498 (OP_SYMBOL (IC_RESULT (ic))->_isparm &&
1499 !OP_SYMBOL (IC_RESULT (ic))->ismyparm))
1508 if (IS_SYMOP (IC_RESULT (dic)) &&
1509 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1514 if (IS_SYMOP (IC_RIGHT (dic)) &&
1515 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1516 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1522 if (IS_SYMOP (IC_LEFT (dic)) &&
1523 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1524 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1530 if (POINTER_SET (dic) &&
1531 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1540 return 0; /* did not find */
1542 /* if the result is on stack or iaccess then it must be
1543 the same atleast one of the operands */
1544 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1545 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1548 /* the operation has only one symbol
1549 operator then we can pack */
1550 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1551 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1554 if (!((IC_LEFT (dic) &&
1555 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1557 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1561 /* found the definition */
1562 /* replace the result with the result of */
1563 /* this assignment and remove this assignment */
1564 IC_RESULT (dic) = IC_RESULT (ic);
1566 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1568 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1570 /* delete from liverange table also
1571 delete from all the points inbetween and the new
1573 for (sic = dic; sic != ic; sic = sic->next)
1575 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1576 if (IS_ITEMP (IC_RESULT (dic)))
1577 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1580 remiCodeFromeBBlock (ebp, ic);
1581 // PENDING: Check vs mcs51
1585 /** Scanning backwards looks for first assig found.
1588 findAssignToSym (operand * op, iCode * ic)
1592 for (dic = ic->prev; dic; dic = dic->prev)
1595 /* if definition by assignment */
1596 if (dic->op == '=' &&
1597 !POINTER_SET (dic) &&
1598 IC_RESULT (dic)->key == op->key)
1599 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1602 /* we are interested only if defined in far space */
1603 /* or in stack space in case of + & - */
1605 /* if assigned to a non-symbol then return
1607 if (!IS_SYMOP (IC_RIGHT (dic)))
1610 /* if the symbol is in far space then
1612 if (isOperandInFarSpace (IC_RIGHT (dic)))
1615 /* for + & - operations make sure that
1616 if it is on the stack it is the same
1617 as one of the three operands */
1618 if ((ic->op == '+' || ic->op == '-') &&
1619 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1622 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1623 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1624 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1632 /* if we find an usage then we cannot delete it */
1633 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1636 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1639 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1643 /* now make sure that the right side of dic
1644 is not defined between ic & dic */
1647 iCode *sic = dic->next;
1649 for (; sic != ic; sic = sic->next)
1650 if (IC_RESULT (sic) &&
1651 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1660 #if !DISABLE_PACKREGSFORSUPPORT
1663 /*-----------------------------------------------------------------*/
1664 /* packRegsForSupport :- reduce some registers for support calls */
1665 /*-----------------------------------------------------------------*/
1667 packRegsForSupport (iCode * ic, eBBlock * ebp)
1670 /* for the left & right operand :- look to see if the
1671 left was assigned a true symbol in far space in that
1672 case replace them */
1673 D (D_ALLOC, ("packRegsForSupport: running on ic %p\n", ic));
1675 if (IS_ITEMP (IC_LEFT (ic)) &&
1676 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1678 iCode *dic = findAssignToSym (IC_LEFT (ic), ic);
1684 /* found it we need to remove it from the
1686 for (sic = dic; sic != ic; sic = sic->next)
1687 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1689 IC_LEFT (ic)->operand.symOperand =
1690 IC_RIGHT (dic)->operand.symOperand;
1691 IC_LEFT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1692 remiCodeFromeBBlock (ebp, dic);
1693 // PENDING: Check vs mcs51
1697 /* do the same for the right operand */
1700 IS_ITEMP (IC_RIGHT (ic)) &&
1701 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1703 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1709 /* found it we need to remove it from the block */
1710 for (sic = dic; sic != ic; sic = sic->next)
1711 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1713 IC_RIGHT (ic)->operand.symOperand =
1714 IC_RIGHT (dic)->operand.symOperand;
1715 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1717 remiCodeFromeBBlock (ebp, dic);
1718 // PENDING: vs mcs51
1726 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1728 /** Will reduce some registers for single use.
1731 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1737 D (D_ALLOC, ("packRegsForOneUse: running on ic %p\n", ic));
1739 /* if returning a literal then do nothing */
1743 /* only upto 2 bytes since we cannot predict
1744 the usage of b, & acc */
1745 if (getSize (operandType (op)) > 2 &&
1750 /* this routine will mark the a symbol as used in one
1751 instruction use only && if the defintion is local
1752 (ie. within the basic block) && has only one definition &&
1753 that definiion is either a return value from a
1754 function or does not contain any variables in
1756 uses = bitVectCopy (OP_USES (op));
1757 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1758 if (!bitVectIsZero (uses)) /* has other uses */
1761 /* if it has only one defintion */
1762 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1763 return NULL; /* has more than one definition */
1765 /* get the that definition */
1767 hTabItemWithKey (iCodehTab,
1768 bitVectFirstBit (OP_DEFS (op)))))
1771 /* found the definition now check if it is local */
1772 if (dic->seq < ebp->fSeq ||
1773 dic->seq > ebp->lSeq)
1774 return NULL; /* non-local */
1776 /* now check if it is the return from a function call */
1777 if (dic->op == CALL || dic->op == PCALL)
1779 if (ic->op != SEND && ic->op != RETURN)
1781 OP_SYMBOL (op)->ruonly = 1;
1787 /* otherwise check that the definition does
1788 not contain any symbols in far space */
1789 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1790 isOperandInFarSpace (IC_RIGHT (dic)) ||
1791 IS_OP_RUONLY (IC_LEFT (ic)) ||
1792 IS_OP_RUONLY (IC_RIGHT (ic)))
1797 /* if pointer set then make sure the pointer is one byte */
1798 if (POINTER_SET (dic))
1801 if (POINTER_GET (dic))
1806 /* also make sure the intervenening instructions
1807 don't have any thing in far space */
1808 for (dic = dic->next; dic && dic != ic; dic = dic->next)
1810 /* if there is an intervening function call then no */
1811 if (dic->op == CALL || dic->op == PCALL)
1813 /* if pointer set then make sure the pointer
1815 if (POINTER_SET (dic))
1818 if (POINTER_GET (dic))
1821 /* if address of & the result is remat the okay */
1822 if (dic->op == ADDRESS_OF &&
1823 OP_SYMBOL (IC_RESULT (dic))->remat)
1826 /* if left or right or result is in far space */
1827 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1828 isOperandInFarSpace (IC_RIGHT (dic)) ||
1829 isOperandInFarSpace (IC_RESULT (dic)) ||
1830 IS_OP_RUONLY (IC_LEFT (dic)) ||
1831 IS_OP_RUONLY (IC_RIGHT (dic)) ||
1832 IS_OP_RUONLY (IC_RESULT (dic)))
1838 OP_SYMBOL (op)->ruonly = 1;
1842 /*-----------------------------------------------------------------*/
1843 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1844 /*-----------------------------------------------------------------*/
1846 isBitwiseOptimizable (iCode * ic)
1848 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
1850 /* bitwise operations are considered optimizable
1851 under the following conditions (Jean-Louis VERN)
1863 if (IS_LITERAL (rtype))
1869 Certian assignments involving pointers can be temporarly stored
1880 #if !DISABLE_PACKREGSFORACCUSE
1883 /** Pack registers for acc use.
1884 When the result of this operation is small and short lived it may
1885 be able to be stored in the accumelator.
1888 packRegsForAccUse (iCode * ic)
1892 /* if + or - then it has to be one byte result */
1893 if ((ic->op == '+' || ic->op == '-')
1894 && getSize (operandType (IC_RESULT (ic))) > 1)
1897 /* if shift operation make sure right side is not a literal */
1898 if (ic->op == RIGHT_OP &&
1899 (isOperandLiteral (IC_RIGHT (ic)) ||
1900 getSize (operandType (IC_RESULT (ic))) > 1))
1903 if (ic->op == LEFT_OP &&
1904 (isOperandLiteral (IC_RIGHT (ic)) ||
1905 getSize (operandType (IC_RESULT (ic))) > 1))
1908 /* has only one definition */
1909 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
1912 /* has only one use */
1913 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
1916 /* and the usage immediately follows this iCode */
1917 if (!(uic = hTabItemWithKey (iCodehTab,
1918 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
1921 if (ic->next != uic)
1924 /* if it is a conditional branch then we definitely can */
1928 if (uic->op == JUMPTABLE)
1932 /* if the usage is not is an assignment or an
1933 arithmetic / bitwise / shift operation then not */
1934 if (POINTER_SET (uic) &&
1935 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
1939 if (uic->op != '=' &&
1940 !IS_ARITHMETIC_OP (uic) &&
1941 !IS_BITWISE_OP (uic) &&
1942 uic->op != LEFT_OP &&
1943 uic->op != RIGHT_OP)
1946 /* if used in ^ operation then make sure right is not a
1948 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
1951 /* if shift operation make sure right side is not a literal */
1952 if (uic->op == RIGHT_OP &&
1953 (isOperandLiteral (IC_RIGHT (uic)) ||
1954 getSize (operandType (IC_RESULT (uic))) > 1))
1957 if (uic->op == LEFT_OP &&
1958 (isOperandLiteral (IC_RIGHT (uic)) ||
1959 getSize (operandType (IC_RESULT (uic))) > 1))
1963 /* make sure that the result of this icode is not on the
1964 stack, since acc is used to compute stack offset */
1965 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
1966 OP_SYMBOL (IC_RESULT (uic))->onStack)
1971 /* if either one of them in far space then we cannot */
1972 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
1973 isOperandInFarSpace (IC_LEFT (uic))) ||
1974 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
1975 isOperandInFarSpace (IC_RIGHT (uic))))
1979 /* if the usage has only one operand then we can */
1980 if (IC_LEFT (uic) == NULL ||
1981 IC_RIGHT (uic) == NULL)
1984 /* make sure this is on the left side if not
1985 a '+' since '+' is commutative */
1986 if (ic->op != '+' &&
1987 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
1990 // See mcs51 ralloc for reasoning
1992 /* if one of them is a literal then we can */
1993 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
1994 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2001 /** This is confusing :) Guess for now */
2002 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2003 (IS_ITEMP (IC_RIGHT (uic)) ||
2004 (IS_TRUE_SYMOP (IC_RIGHT (uic)))))
2007 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2008 (IS_ITEMP (IC_LEFT (uic)) ||
2009 (IS_TRUE_SYMOP (IC_LEFT (uic)))))
2013 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2018 packRegsForHLUse (iCode * ic)
2022 /* PENDING: Could do IFX */
2028 /* has only one definition */
2029 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2031 D (D_HLUSE, (" + Dropping as has more than one def\n"));
2035 /* has only one use */
2036 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2038 D (D_HLUSE, (" + Dropping as has more than one use\n"));
2042 /* and the usage immediately follows this iCode */
2043 if (!(uic = hTabItemWithKey (iCodehTab,
2044 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2046 D (D_HLUSE, (" + Dropping as usage isn't in this block\n"));
2050 if (ic->next != uic)
2052 D (D_HLUSE, (" + Dropping as usage doesn't follow this\n"));
2061 if (getSize (operandType (IC_RESULT (ic))) != 2 ||
2062 (IC_LEFT(uic) && getSize (operandType (IC_LEFT (uic))) != 2) ||
2063 (IC_RIGHT(uic) && getSize (operandType (IC_RIGHT (uic))) != 2))
2065 D (D_HLUSE, (" + Dropping as the result size is not 2\n"));
2071 if (ic->op == CAST && uic->op == IPUSH)
2073 if (ic->op == ADDRESS_OF && uic->op == IPUSH)
2075 if (ic->op == ADDRESS_OF && POINTER_GET (uic) && IS_ITEMP( IC_RESULT (uic)))
2077 if (ic->op == CALL && ic->parmBytes == 0 && (uic->op == '-' || uic->op == '+'))
2082 /* Case of assign a constant to offset in a static array. */
2083 if (ic->op == '+' && IS_VALOP (IC_RIGHT (ic)))
2085 if (uic->op == '=' && POINTER_SET (uic))
2089 else if (uic->op == IPUSH && getSize (operandType (IC_LEFT (uic))) == 2)
2096 D (D_HLUSE, (" + Dropping as it's a bad op\n"));
2099 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_SCRATCH;
2103 opPreservesA (iCode * ic, iCode * uic)
2107 /* If we've gotten this far then the thing to compare must be
2108 small enough and must be in A.
2113 if (uic->op == JUMPTABLE)
2115 D (D_ACCUSE2, (" + Dropping as operation is a Jumptable\n"));
2119 /* A pointer assign preserves A if A is the left value. */
2120 if (uic->op == '=' && POINTER_SET (uic))
2125 /* if the usage has only one operand then we can */
2126 /* PENDING: check */
2127 if (IC_LEFT (uic) == NULL ||
2128 IC_RIGHT (uic) == NULL)
2130 D (D_ACCUSE2, (" + Dropping as operation has only one operand\n"));
2134 /* PENDING: check this rule */
2135 if (getSize (operandType (IC_RESULT (uic))) > 1)
2137 D (D_ACCUSE2, (" + Dropping as operation has size is too big\n"));
2142 /* Disabled all of the old rules as they weren't verified and have
2143 caused at least one problem.
2149 opIgnoresA (iCode * ic, iCode * uic)
2151 /* A increment of an iTemp by a constant is OK. */
2152 if ( uic->op == '+' &&
2153 IS_ITEMP (IC_LEFT (uic)) &&
2154 IS_ITEMP (IC_RESULT (uic)) &&
2155 IS_OP_LITERAL (IC_RIGHT (uic)))
2157 unsigned int icount = (unsigned int) floatFromVal (IC_RIGHT (uic)->operand.valOperand);
2159 /* Being an ITEMP means that we're already a symbol. */
2161 IC_RESULT (uic)->operand.symOperand->key == IC_LEFT (uic)->operand.symOperand->key
2172 /* Some optimisation cases:
2184 ; genAssign (pointer)
2188 want to optimise down to:
2194 So genPointer get is OK
2195 genPlus where the right is constant, left is iTemp, and result is same as left
2196 genAssign (pointer) is OK
2207 ; genAssign (pointer)
2208 ; AOP_STK for _strcpy_to_1_1
2213 want to optimise down to:
2219 So genIfx where IC_COND has size of 1 and is a constant.
2222 /** Pack registers for acc use.
2223 When the result of this operation is small and short lived it may
2224 be able to be stored in the accumulator.
2226 Note that the 'A preserving' list is currently emperical :)
2229 packRegsForAccUse2 (iCode * ic)
2233 D (D_ALLOC, ("packRegsForAccUse2: running on ic %p\n", ic));
2235 /* Filter out all but those 'good' commands */
2237 !POINTER_GET (ic) &&
2239 !IS_BITWISE_OP (ic) &&
2243 ic->op != GETHBIT &&
2246 D (D_ACCUSE2, (" + Dropping as not a 'good' source command\n"));
2250 /* if + or - then it has to be one byte result.
2253 if ((ic->op == '+' || ic->op == '-')
2254 && getSize (operandType (IC_RESULT (ic))) > 1)
2256 D (D_ACCUSE2, (" + Dropping as it's a big + or -\n"));
2260 /* has only one definition */
2261 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2263 D (D_ACCUSE2, (" + Dropping as it has more than one definition\n"));
2267 /* Right. We may be able to propagate it through if:
2268 For each in the chain of uses the intermediate is OK.
2270 /* Get next with 'uses result' bit on
2271 If this->next == next
2272 Validate use of next
2273 If OK, increase count
2275 /* and the usage immediately follows this iCode */
2276 if (!(uic = hTabItemWithKey (iCodehTab,
2277 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2279 D (D_ACCUSE2, (" + Dropping as usage does not follow first\n"));
2284 /* Create a copy of the OP_USES bit vect */
2285 bitVect *uses = bitVectCopy (OP_USES (IC_RESULT (ic)));
2287 iCode *scan = ic, *next;
2291 setBit = bitVectFirstBit (uses);
2292 next = hTabItemWithKey (iCodehTab, setBit);
2293 if (scan->next == next)
2295 D (D_ACCUSE2_VERBOSE, (" ! Is next in line\n"));
2297 bitVectUnSetBit (uses, setBit);
2298 /* Still contigous. */
2299 if (!opPreservesA (ic, next))
2301 D (D_ACCUSE2, (" + Dropping as operation doesn't preserve A\n"));
2304 D (D_ACCUSE2_VERBOSE, (" ! Preserves A, so continue scanning\n"));
2307 else if (scan->next == NULL && bitVectnBitsOn (uses) == 1 && next != NULL)
2309 if (next->prev == NULL)
2311 if (!opPreservesA (ic, next))
2313 D (D_ACCUSE2, (" + Dropping as operation doesn't preserve A #2\n"));
2316 bitVectUnSetBit (uses, setBit);
2321 D (D_ACCUSE2, (" + Dropping as last in list and next doesn't start a block\n"));
2325 else if (scan->next == NULL)
2327 D (D_ACCUSE2, (" + Dropping as hit the end of the list\n"));
2328 D (D_ACCUSE2, (" + Next in htab: %p\n", next));
2333 if (opIgnoresA (ic, scan->next))
2337 D (D_ACCUSE2_VERBOSE, (" ! Op ignores A, so continue scanning\n"));
2341 D (D_ACCUSE2, (" + Dropping as parts are not consecuitive and intermediate might use A\n"));
2346 while (!bitVectIsZero (uses));
2348 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2352 /* OLD CODE FOLLOWS */
2353 /* if it is a conditional branch then we definitely can
2361 if (uic->op == JUMPTABLE)
2365 /* if the usage is not is an assignment or an
2366 arithmetic / bitwise / shift operation then not.
2367 MLH: Pending: Invalid. Our pointer sets are always peechy.
2370 if (POINTER_SET (uic) &&
2371 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2373 printf ("e5 %u\n", getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)));
2379 if (uic->op != '=' &&
2380 !IS_ARITHMETIC_OP (uic) &&
2381 !IS_BITWISE_OP (uic) &&
2382 uic->op != LEFT_OP &&
2383 uic->op != RIGHT_OP)
2389 /* if used in ^ operation then make sure right is not a
2391 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2394 /* if shift operation make sure right side is not a literal */
2395 if (uic->op == RIGHT_OP &&
2396 (isOperandLiteral (IC_RIGHT (uic)) ||
2397 getSize (operandType (IC_RESULT (uic))) > 1))
2400 if (uic->op == LEFT_OP &&
2401 (isOperandLiteral (IC_RIGHT (uic)) ||
2402 getSize (operandType (IC_RESULT (uic))) > 1))
2406 /* make sure that the result of this icode is not on the
2407 stack, since acc is used to compute stack offset */
2408 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2409 OP_SYMBOL (IC_RESULT (uic))->onStack)
2414 /* if either one of them in far space then we cannot */
2415 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2416 isOperandInFarSpace (IC_LEFT (uic))) ||
2417 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2418 isOperandInFarSpace (IC_RIGHT (uic))))
2422 /* if the usage has only one operand then we can */
2423 if (IC_LEFT (uic) == NULL ||
2424 IC_RIGHT (uic) == NULL)
2427 /* make sure this is on the left side if not
2428 a '+' since '+' is commutative */
2429 if (ic->op != '+' &&
2430 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2433 /* if one of them is a literal then we can */
2434 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2435 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2441 /** This is confusing :) Guess for now */
2442 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2443 (IS_ITEMP (IC_RIGHT (uic)) ||
2444 (IS_TRUE_SYMOP (IC_RIGHT (uic)))))
2447 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2448 (IS_ITEMP (IC_LEFT (uic)) ||
2449 (IS_TRUE_SYMOP (IC_LEFT (uic)))))
2453 printf ("acc ok!\n");
2454 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2457 /** Does some transformations to reduce register pressure.
2460 packRegisters (eBBlock * ebp)
2465 D (D_ALLOC, ("packRegisters: entered.\n"));
2467 while (1 && !DISABLE_PACK_ASSIGN)
2470 /* look for assignments of the form */
2471 /* iTempNN = TRueSym (someoperation) SomeOperand */
2473 /* TrueSym := iTempNN:1 */
2474 for (ic = ebp->sch; ic; ic = ic->next)
2476 /* find assignment of the form TrueSym := iTempNN:1 */
2477 if (ic->op == '=' && !POINTER_SET (ic))
2478 change += packRegsForAssign (ic, ebp);
2484 for (ic = ebp->sch; ic; ic = ic->next)
2486 /* Safe: address of a true sym is always constant. */
2487 /* if this is an itemp & result of a address of a true sym
2488 then mark this as rematerialisable */
2489 D (D_ALLOC, ("packRegisters: looping on ic %p\n", ic));
2491 if (ic->op == ADDRESS_OF &&
2492 IS_ITEMP (IC_RESULT (ic)) &&
2493 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2494 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2495 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2498 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2499 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2500 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2503 /* Safe: just propagates the remat flag */
2504 /* if straight assignment then carry remat flag if this is the
2506 if (ic->op == '=' &&
2507 !POINTER_SET (ic) &&
2508 IS_SYMOP (IC_RIGHT (ic)) &&
2509 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2510 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2513 OP_SYMBOL (IC_RESULT (ic))->remat =
2514 OP_SYMBOL (IC_RIGHT (ic))->remat;
2515 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2516 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2519 /* if the condition of an if instruction is defined in the
2520 previous instruction then mark the itemp as a conditional */
2521 if ((IS_CONDITIONAL (ic) ||
2522 ((ic->op == BITWISEAND ||
2525 isBitwiseOptimizable (ic))) &&
2526 ic->next && ic->next->op == IFX &&
2527 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2528 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2529 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2532 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2537 /* reduce for support function calls */
2538 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2539 packRegsForSupport (ic, ebp);
2542 /* if pointer set & left has a size more than
2543 one and right is not in far space */
2544 if (!DISABLE_PACK_ONE_USE &&
2546 /* MLH: no such thing.
2547 !isOperandInFarSpace(IC_RIGHT(ic)) && */
2548 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2549 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2550 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2553 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2556 /* if pointer get */
2557 if (!DISABLE_PACK_ONE_USE &&
2559 /* MLH: dont have far space
2560 !isOperandInFarSpace(IC_RESULT(ic))&& */
2561 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2562 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2563 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2566 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2569 /* pack registers for accumulator use, when the result of an
2570 arithmetic or bit wise operation has only one use, that use is
2571 immediately following the defintion and the using iCode has
2572 only one operand or has two operands but one is literal & the
2573 result of that operation is not on stack then we can leave the
2574 result of this operation in acc:b combination */
2576 if (!DISABLE_PACK_HL && IS_ITEMP (IC_RESULT (ic)))
2578 packRegsForHLUse (ic);
2581 if (!DISABLE_PACK_ACC && IS_ITEMP (IC_RESULT (ic)) &&
2582 getSize (operandType (IC_RESULT (ic))) == 1)
2584 packRegsForAccUse2 (ic);
2589 /** Joins together two byte constant pushes into one word push.
2592 joinPushes (iCode *lic)
2596 for (ic = lic; ic; ic = ic->next)
2603 /* Anything past this? */
2608 /* This and the next pushes? */
2609 if (ic->op != IPUSH || uic->op != IPUSH)
2613 /* Both literals? */
2614 if ( !IS_OP_LITERAL (IC_LEFT (ic)) || !IS_OP_LITERAL (IC_LEFT (uic)))
2618 /* Both characters? */
2619 if ( getSize (operandType (IC_LEFT (ic))) != 1 || getSize (operandType (IC_LEFT (uic))) != 1)
2623 /* Pull out the values, make a new type, and create the new iCode for it.
2625 first = (int)operandLitValue ( IC_LEFT (ic));
2626 second = (int)operandLitValue ( IC_LEFT (uic));
2628 sprintf (buffer, "%u", ((first << 8) | (second & 0xFF)) & 0xFFFFU);
2629 val = constVal (buffer);
2630 SPEC_NOUN (val->type) = V_INT;
2631 IC_LEFT (ic)->operand.valOperand = val;
2633 /* Now remove the second one from the list. */
2634 ic->next = uic->next;
2637 /* Patch up the reverse link */
2638 uic->next->prev = ic;
2645 /*-----------------------------------------------------------------*/
2646 /* assignRegisters - assigns registers to each live range as need */
2647 /*-----------------------------------------------------------------*/
2649 z80_assignRegisters (eBBlock ** ebbs, int count)
2654 D (D_ALLOC, ("\n-> z80_assignRegisters: entered.\n"));
2656 setToNull ((void *) &_G.funcrUsed);
2657 _G.stackExtend = _G.dataExtend = 0;
2661 /* DE is required for the code gen. */
2662 _G.nRegs = GBZ80_MAX_REGS;
2663 regsZ80 = _gbz80_regs;
2667 _G.nRegs = Z80_MAX_REGS;
2668 regsZ80 = _z80_regs;
2671 /* change assignments this will remove some
2672 live ranges reducing some register pressure */
2673 for (i = 0; i < count; i++)
2674 packRegisters (ebbs[i]);
2676 if (options.dump_pack)
2677 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2679 /* first determine for each live range the number of
2680 registers & the type of registers required for each */
2683 /* and serially allocate registers */
2684 serialRegAssign (ebbs, count);
2686 /* if stack was extended then tell the user */
2689 /* werror(W_TOOMANY_SPILS,"stack", */
2690 /* _G.stackExtend,currFunc->name,""); */
2696 /* werror(W_TOOMANY_SPILS,"data space", */
2697 /* _G.dataExtend,currFunc->name,""); */
2701 if (options.dump_rassgn) {
2702 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2703 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2706 /* after that create the register mask
2707 for each of the instruction */
2708 createRegMask (ebbs, count);
2710 /* now get back the chain */
2711 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2713 ic = joinPushes (ic);
2715 /* redo that offsets for stacked automatic variables */
2716 redoStackOffsets ();
2720 /* free up any stackSpil locations allocated */
2721 applyToSet (_G.stackSpil, deallocStackSpil);
2723 setToNull ((void **) &_G.stackSpil);
2724 setToNull ((void **) &_G.spiltSet);
2725 /* mark all registers as free */