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, ix, iy, and a are reserved for the code generator,
11 leaving bc and de for allocation. The extra register pressure
12 from reserving hl is made up for by how much easier the sub
13 operations become. You could swap hl for iy if the undocumented
14 iyl/iyh instructions are available.
16 The stack frame is the common ix-bp style. Basically:
21 ix+0: calling functions ix
24 sp: end of local varibles
26 There is currently no support for bit spaces or banked functions.
28 This program is free software; you can redistribute it and/or
29 modify it under the terms of the GNU General Public License as
30 published by the Free Software Foundation; either version 2, or (at
31 your option) any later version. This program is distributed in the
32 hope that it will be useful, but WITHOUT ANY WARRANTY; without even
33 the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
34 PURPOSE. See the GNU General Public License for more details.
36 You should have received a copy of the GNU General Public License
37 along with this program; if not, write to the Free Software
38 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
39 USA. In other words, you are welcome to use, share and improve
40 this program. You are forbidden to forbid anyone else to use,
41 share and improve what you give them. Help stamp out
49 DISABLE_PACK_ASSIGN = 0,
56 #define D(_a, _s) if (_a) { printf _s; fflush(stdout); }
61 /*-----------------------------------------------------------------*/
62 /* At this point we start getting processor specific although */
63 /* some routines are non-processor specific & can be reused when */
64 /* targetting other processors. The decision for this will have */
65 /* to be made on a routine by routine basis */
66 /* routines used to pack registers are most definitely not reusable*/
67 /* since the pack the registers depending strictly on the MCU */
68 /*-----------------------------------------------------------------*/
70 bitVect *spiltSet = NULL ;
71 set *stackSpil = NULL;
72 bitVect *regAssigned = NULL;
75 extern void genZ80Code(iCode *);
76 bitVect *funcrUsed = NULL; /* registers used in a function */
81 /** Set to help debug register pressure related problems */
82 #define DEBUG_FAKE_EXTRA_REGS 0
84 static regs _gbz80_regs[] = {
85 { REG_GPR, C_IDX , "c", 1 },
86 { REG_GPR, B_IDX , "b", 1 },
87 { REG_CND, CND_IDX, "c", 1}
90 static regs _z80_regs[] = {
91 { REG_GPR, C_IDX , "c", 1 },
92 { REG_GPR, B_IDX , "b", 1 },
93 { REG_GPR, E_IDX , "e", 1 },
94 { REG_GPR, D_IDX , "d", 1 },
95 /* { REG_GPR, L_IDX , "l", 1 },
96 { REG_GPR, H_IDX , "h", 1 },*/
97 #if DEBUG_FAKE_EXTRA_REGS
98 { REG_GPR, M_IDX , "m", 1 },
99 { REG_GPR, N_IDX , "n", 1 },
100 { REG_GPR, O_IDX , "o", 1 },
101 { REG_GPR, P_IDX , "p", 1 },
102 { REG_GPR, Q_IDX , "q", 1 },
103 { REG_GPR, R_IDX , "r", 1 },
104 { REG_GPR, S_IDX , "s", 1 },
105 { REG_GPR, T_IDX , "t", 1 },
107 { REG_CND, CND_IDX, "c", 1}
112 /** Number of usable registers (all but C) */
113 #define Z80_MAX_REGS ((sizeof(_z80_regs)/sizeof(_z80_regs[0]))-1)
114 #define GBZ80_MAX_REGS ((sizeof(_gbz80_regs)/sizeof(_gbz80_regs[0]))-1)
116 static void spillThis (symbol *);
118 /** Allocates register of given type.
119 'type' is not used on the z80 version. It was used to select
120 between pointer and general purpose registers on the mcs51 version.
122 @return Pointer to the newly allocated register.
124 static regs *allocReg (short type)
128 for ( i = 0 ; i < _nRegs ; i++ ) {
129 /* For now we allocate from any free */
130 if (regsZ80[i].isFree ) {
131 regsZ80[i].isFree = 0;
134 bitVectSetBit(currFunc->regsUsed,i);
135 D(D_ALLOC, ("allocReg: alloced %zr\n", ®sZ80[i]));
139 D(D_ALLOC, ("allocReg: No free.\n"));
143 /** Returns pointer to register wit index number
145 regs *regWithIdx (int idx)
149 for (i=0;i < _nRegs;i++)
150 if (regsZ80[i].rIdx == idx)
153 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
154 "regWithIdx not found");
158 /** Frees a register.
160 static void freeReg (regs *reg)
162 wassert(!reg->isFree);
164 D(D_ALLOC, ("freeReg: freed %zr\n", reg));
168 /** Returns number of free registers.
170 static int nFreeRegs (int type)
175 for (i = 0 ; i < _nRegs; i++ ) {
176 /* For now only one reg type */
177 if (regsZ80[i].isFree)
183 /** Free registers with type.
185 static int nfreeRegsType (int type)
188 if (type == REG_PTR) {
189 if ((nfr = nFreeRegs(type)) == 0)
190 return nFreeRegs(REG_GPR);
193 return nFreeRegs(type);
198 /*-----------------------------------------------------------------*/
199 /* allDefsOutOfRange - all definitions are out of a range */
200 /*-----------------------------------------------------------------*/
201 static bool allDefsOutOfRange (bitVect *defs,int fseq, int toseq)
208 for ( i = 0 ;i < defs->size ; i++ ) {
211 if (bitVectBitValue(defs,i) &&
212 (ic = hTabItemWithKey(iCodehTab,i)) &&
213 ( ic->seq >= fseq && ic->seq <= toseq))
223 /*-----------------------------------------------------------------*/
224 /* computeSpillable - given a point find the spillable live ranges */
225 /*-----------------------------------------------------------------*/
226 static bitVect *computeSpillable (iCode *ic)
230 /* spillable live ranges are those that are live at this
231 point . the following categories need to be subtracted
233 a) - those that are already spilt
234 b) - if being used by this one
235 c) - defined by this one */
237 spillable = bitVectCopy(ic->rlive);
239 bitVectCplAnd(spillable,spiltSet); /* those already spilt */
241 bitVectCplAnd(spillable,ic->uses); /* used in this one */
242 bitVectUnSetBit(spillable,ic->defKey);
243 spillable = bitVectIntersect(spillable,regAssigned);
248 /*-----------------------------------------------------------------*/
249 /* noSpilLoc - return true if a variable has no spil location */
250 /*-----------------------------------------------------------------*/
251 static int noSpilLoc (symbol *sym, eBBlock *ebp,iCode *ic)
253 return (sym->usl.spillLoc ? 0 : 1);
256 /*-----------------------------------------------------------------*/
257 /* hasSpilLoc - will return 1 if the symbol has spil location */
258 /*-----------------------------------------------------------------*/
259 static int hasSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
261 return (sym->usl.spillLoc ? 1 : 0);
264 /** Will return 1 if the remat flag is set.
265 A symbol is rematerialisable if it doesnt need to be allocated
266 into registers at creation as it can be re-created at any time -
267 i.e. it's constant in some way.
269 static int rematable (symbol *sym, eBBlock *ebp, iCode *ic)
274 /*-----------------------------------------------------------------*/
275 /* allLRs - return true for all */
276 /*-----------------------------------------------------------------*/
277 static int allLRs (symbol *sym, eBBlock *ebp, iCode *ic)
282 /*-----------------------------------------------------------------*/
283 /* liveRangesWith - applies function to a given set of live range */
284 /*-----------------------------------------------------------------*/
285 set *liveRangesWith (bitVect *lrs, int (func)(symbol *,eBBlock *, iCode *),
286 eBBlock *ebp, iCode *ic)
291 if (!lrs || !lrs->size)
294 for ( i = 1 ; i < lrs->size ; i++ ) {
296 if (!bitVectBitValue(lrs,i))
299 /* if we don't find it in the live range
300 hash table we are in serious trouble */
301 if (!(sym = hTabItemWithKey(liveRanges,i))) {
302 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
303 "liveRangesWith could not find liveRange");
307 if (func(sym,ebp,ic) && bitVectBitValue(regAssigned,sym->key))
308 addSetHead(&rset,sym);
315 /*-----------------------------------------------------------------*/
316 /* leastUsedLR - given a set determines which is the least used */
317 /*-----------------------------------------------------------------*/
318 symbol *leastUsedLR (set *sset)
320 symbol *sym = NULL, *lsym = NULL ;
322 sym = lsym = setFirstItem(sset);
327 for (; lsym; lsym = setNextItem(sset)) {
329 /* if usage is the same then prefer
330 the spill the smaller of the two */
331 if ( lsym->used == sym->used )
332 if (getSize(lsym->type) < getSize(sym->type))
336 if (lsym->used < sym->used )
341 setToNull((void **)&sset);
346 /*-----------------------------------------------------------------*/
347 /* noOverLap - will iterate through the list looking for over lap */
348 /*-----------------------------------------------------------------*/
349 static int noOverLap (set *itmpStack, symbol *fsym)
353 for (sym = setFirstItem(itmpStack); sym;
354 sym = setNextItem(itmpStack)) {
355 if (sym->liveTo > fsym->liveFrom )
362 /*-----------------------------------------------------------------*/
363 /* isFree - will return 1 if the a free spil location is found */
364 /*-----------------------------------------------------------------*/
368 V_ARG(symbol **,sloc);
369 V_ARG(symbol *,fsym);
371 /* if already found */
375 /* if it is free && and the itmp assigned to
376 this does not have any overlapping live ranges
377 with the one currently being assigned and
378 the size can be accomodated */
380 noOverLap(sym->usl.itmpStack,fsym) &&
381 getSize(sym->type) >= getSize(fsym->type)) {
389 /*-----------------------------------------------------------------*/
390 /* createStackSpil - create a location on the stack to spil */
391 /*-----------------------------------------------------------------*/
392 symbol *createStackSpil (symbol *sym)
396 D(D_ALLOC, ("createStackSpil: for sym %zs\n", sym));
398 /* first go try and find a free one that is already
399 existing on the stack */
400 if (applyToSet(stackSpil,isFree,&sloc, sym)) {
401 /* found a free one : just update & return */
402 sym->usl.spillLoc = sloc;
405 addSetHead(&sloc->usl.itmpStack,sym);
406 D(D_ALLOC, ("createStackSpil: found existing\n"));
410 /* could not then have to create one , this is the hard part
411 we need to allocate this on the stack : this is really a
412 hack!! but cannot think of anything better at this time */
414 sprintf(buffer,"sloc%d",slocNum++);
415 sloc = newiTemp(buffer);
417 /* set the type to the spilling symbol */
418 sloc->type = copyLinkChain(sym->type);
419 sloc->etype = getSpec(sloc->type);
420 SPEC_SCLS(sloc->etype) = S_AUTO ;
422 /* we don't allow it to be allocated`
423 onto the external stack since : so we
424 temporarily turn it off ; we also
425 turn off memory model to prevent
426 the spil from going to the external storage
427 and turn off overlaying
431 sloc->isref = 1; /* to prevent compiler warning */
433 /* if it is on the stack then update the stack */
434 if (IN_STACK(sloc->etype)) {
435 currFunc->stack += getSize(sloc->type);
436 stackExtend += getSize(sloc->type);
438 dataExtend += getSize(sloc->type);
440 /* add it to the stackSpil set */
441 addSetHead(&stackSpil,sloc);
442 sym->usl.spillLoc = sloc;
445 /* add it to the set of itempStack set
446 of the spill location */
447 addSetHead(&sloc->usl.itmpStack,sym);
449 D(D_ALLOC, ("createStackSpil: created new\n"));
453 /*-----------------------------------------------------------------*/
454 /* isSpiltOnStack - returns true if the spil location is on stack */
455 /*-----------------------------------------------------------------*/
456 bool isSpiltOnStack (symbol *sym)
466 /* if (sym->stackSpil) */
469 if (!sym->usl.spillLoc)
472 etype = getSpec(sym->usl.spillLoc->type);
479 /*-----------------------------------------------------------------*/
480 /* spillThis - spils a specific operand */
481 /*-----------------------------------------------------------------*/
482 static void spillThis (symbol *sym)
486 D(D_ALLOC, ("spillThis: spilling %zs\n", sym));
488 /* if this is rematerializable or has a spillLocation
489 we are okay, else we need to create a spillLocation
491 if (!(sym->remat || sym->usl.spillLoc))
492 createStackSpil (sym);
494 /* mark it has spilt & put it in the spilt set */
496 spiltSet = bitVectSetBit(spiltSet,sym->key);
498 bitVectUnSetBit(regAssigned,sym->key);
500 for (i = 0 ; i < sym->nRegs ; i++) {
502 freeReg(sym->regs[i]);
507 /* if spilt on stack then free up r0 & r1
508 if they could have been assigned to some
510 if (sym->usl.spillLoc && !sym->remat)
511 sym->usl.spillLoc->allocreq = 1;
515 /** Select a iTemp to spil : rather a simple procedure.
517 symbol *selectSpil (iCode *ic, eBBlock *ebp, symbol *forSym)
519 bitVect *lrcs= NULL ;
523 D(D_ALLOC, ("selectSpil: finding spill for ic %zi\n", ic));
524 /* get the spillable live ranges */
525 lrcs = computeSpillable (ic);
527 /* get all live ranges that are rematerizable */
528 if ((selectS = liveRangesWith(lrcs,rematable,ebp,ic))) {
529 D(D_ALLOC, ("selectSpil: using remat.\n"));
530 /* return the least used of these */
531 return leastUsedLR(selectS);
535 /* get live ranges with spillLocations in direct space */
536 if ((selectS = liveRangesWith(lrcs,directSpilLoc,ebp,ic))) {
537 sym = leastUsedLR(selectS);
538 strcpy(sym->rname,(sym->usl.spillLoc->rname[0] ?
539 sym->usl.spillLoc->rname :
540 sym->usl.spillLoc->name));
542 /* mark it as allocation required */
543 sym->usl.spillLoc->allocreq = 1;
547 /* if the symbol is local to the block then */
548 if (forSym->liveTo < ebp->lSeq ) {
550 /* check if there are any live ranges allocated
551 to registers that are not used in this block */
552 if (!blockSpil && (selectS = liveRangesWith(lrcs,notUsedInBlock,ebp,ic))) {
553 sym = leastUsedLR(selectS);
554 /* if this is not rematerializable */
562 /* check if there are any live ranges that not
563 used in the remainder of the block */
564 if (!blockSpil && (selectS = liveRangesWith(lrcs,notUsedInRemaining,ebp,ic))) {
565 sym = leastUsedLR (selectS);
573 /* find live ranges with spillocation && not used as pointers */
574 if ((selectS = liveRangesWith(lrcs,hasSpilLocnoUptr,ebp,ic))) {
576 sym = leastUsedLR(selectS);
577 /* mark this as allocation required */
578 sym->usl.spillLoc->allocreq = 1;
583 /* find live ranges with spillocation */
584 if ((selectS = liveRangesWith(lrcs,hasSpilLoc,ebp,ic))) {
585 D(D_ALLOC, ("selectSpil: using with spill.\n"));
586 sym = leastUsedLR(selectS);
587 sym->usl.spillLoc->allocreq = 1;
591 /* couldn't find then we need to create a spil
592 location on the stack , for which one? the least
594 if ((selectS = liveRangesWith(lrcs,noSpilLoc,ebp,ic))) {
595 D(D_ALLOC, ("selectSpil: creating new spill.\n"));
596 /* return a created spil location */
597 sym = createStackSpil(leastUsedLR(selectS));
598 sym->usl.spillLoc->allocreq = 1;
602 /* this is an extreme situation we will spill
603 this one : happens very rarely but it does happen */
604 D(D_ALLOC, ("selectSpil: using spillThis.\n"));
605 spillThis ( forSym );
610 /** Spil some variable & mark registers as free.
611 A spill occurs when an iTemp wont fit into the available registers.
613 bool spilSomething (iCode *ic, eBBlock *ebp, symbol *forSym)
618 D(D_ALLOC, ("spilSomething: spilling on ic %zi\n", ic));
620 /* get something we can spil */
621 ssym = selectSpil(ic,ebp,forSym);
623 /* mark it as spilt */
625 spiltSet = bitVectSetBit(spiltSet,ssym->key);
627 /* mark it as not register assigned &
628 take it away from the set */
629 bitVectUnSetBit(regAssigned,ssym->key);
631 /* mark the registers as free */
632 for (i = 0 ; i < ssym->nRegs ;i++ )
634 freeReg(ssym->regs[i]);
636 /* if spilt on stack then free up r0 & r1
637 if they could have been assigned to as gprs */
638 if (!ptrRegReq && isSpiltOnStack(ssym) ) {
640 spillLRWithPtrReg(ssym);
643 /* if this was a block level spil then insert push & pop
644 at the start & end of block respectively */
645 if (ssym->blockSpil) {
646 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
647 /* add push to the start of the block */
648 addiCodeToeBBlock(ebp,nic,( ebp->sch->op == LABEL ?
649 ebp->sch->next : ebp->sch));
650 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
651 /* add pop to the end of the block */
652 addiCodeToeBBlock(ebp,nic,NULL);
655 /* if spilt because not used in the remainder of the
656 block then add a push before this instruction and
657 a pop at the end of the block */
658 if (ssym->remainSpil) {
660 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
661 /* add push just before this instruction */
662 addiCodeToeBBlock(ebp,nic,ic);
664 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
665 /* add pop to the end of the block */
666 addiCodeToeBBlock(ebp,nic,NULL);
670 D(D_ALLOC, ("spilSomething: done.\n"));
678 /** Will try for GPR if not spil.
680 regs *getRegGpr (iCode *ic, eBBlock *ebp,symbol *sym)
684 D(D_ALLOC, ("getRegGpr: on ic %zi\n"));
686 /* try for gpr type */
687 if ((reg = allocReg(REG_GPR))) {
688 D(D_ALLOC, ("getRegGpr: got a reg.\n"));
692 /* we have to spil */
693 if (!spilSomething (ic,ebp,sym)) {
694 D(D_ALLOC, ("getRegGpr: have to spill.\n"));
698 /* this looks like an infinite loop but
699 in really selectSpil will abort */
703 /** Symbol has a given register.
705 static bool symHasReg(symbol *sym,regs *reg)
709 for ( i = 0 ; i < sym->nRegs ; i++)
710 if (sym->regs[i] == reg)
716 /** Check the live to and if they have registers & are not spilt then
717 free up the registers
719 static void deassignLRs (iCode *ic, eBBlock *ebp)
725 for (sym = hTabFirstItem(liveRanges,&k); sym;
726 sym = hTabNextItem(liveRanges,&k)) {
729 /* if it does not end here */
730 if (sym->liveTo > ic->seq )
733 /* if it was spilt on stack then we can
734 mark the stack spil location as free */
736 if (sym->stackSpil) {
737 sym->usl.spillLoc->isFree = 1;
743 if (!bitVectBitValue(regAssigned,sym->key))
746 /* special case check if this is an IFX &
747 the privious one was a pop and the
748 previous one was not spilt then keep track
750 if (ic->op == IFX && ic->prev &&
751 ic->prev->op == IPOP &&
752 !ic->prev->parmPush &&
753 !OP_SYMBOL(IC_LEFT(ic->prev))->isspilt)
754 psym = OP_SYMBOL(IC_LEFT(ic->prev));
756 D(D_ALLOC, ("deassignLRs: in loop on sym %zs", sym));
761 bitVectUnSetBit(regAssigned,sym->key);
763 /* if the result of this one needs registers
764 and does not have it then assign it right
767 ! (SKIP_IC2(ic) || /* not a special icode */
768 ic->op == JUMPTABLE ||
773 (result = OP_SYMBOL(IC_RESULT(ic))) && /* has a result */
774 result->liveTo > ic->seq && /* and will live beyond this */
775 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
776 result->regType == sym->regType && /* same register types */
777 result->nRegs && /* which needs registers */
778 ! result->isspilt && /* and does not already have them */
780 ! bitVectBitValue(regAssigned,result->key) &&
781 /* the number of free regs + number of regs in this LR
782 can accomodate the what result Needs */
783 ((nfreeRegsType(result->regType) +
784 sym->nRegs) >= result->nRegs)
786 for (i = 0 ; i < max(sym->nRegs,result->nRegs) ; i++) {
788 result->regs[i] = sym->regs[i] ;
790 result->regs[i] = getRegGpr (ic,ebp,result);
792 /* if the allocation falied which means
793 this was spilt then break */
794 if (!result->regs[i]) {
801 regAssigned = bitVectSetBit(regAssigned,result->key);
804 /* free the remaining */
805 for (; i < sym->nRegs ; i++) {
807 if (!symHasReg(psym,sym->regs[i]))
808 freeReg(sym->regs[i]);
810 freeReg(sym->regs[i]);
811 // sym->regs[i] = NULL;
818 /** Reassign this to registers.
820 static void reassignLR (operand *op)
822 symbol *sym = OP_SYMBOL(op);
825 D(D_ALLOC, ("reassingLR: on sym %zs\n", sym));
827 /* not spilt any more */
828 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
829 bitVectUnSetBit(spiltSet,sym->key);
831 regAssigned = bitVectSetBit(regAssigned,sym->key);
835 for (i=0;i<sym->nRegs;i++)
836 sym->regs[i]->isFree = 0;
839 /** Determines if allocating will cause a spill.
841 static int willCauseSpill ( int nr, int rt)
843 /* first check if there are any avlb registers
844 of te type required */
845 if (nFreeRegs(0) >= nr)
848 /* it will cause a spil */
852 /** The allocator can allocate same registers to result and operand,
853 if this happens make sure they are in the same position as the operand
854 otherwise chaos results.
856 static void positionRegs (symbol *result, symbol *opsym, int lineno)
858 int count = min(result->nRegs,opsym->nRegs);
859 int i , j = 0, shared = 0;
861 D(D_ALLOC, ("positionRegs: on result %zs opsum %zs line %u\n", result, opsym, lineno));
863 /* if the result has been spilt then cannot share */
868 /* first make sure that they actually share */
869 for ( i = 0 ; i < count; i++ ) {
870 for (j = 0 ; j < count ; j++ ) {
871 if (result->regs[i] == opsym->regs[j] && i !=j) {
879 regs *tmp = result->regs[i];
880 result->regs[i] = result->regs[j];
881 result->regs[j] = tmp;
886 /** Try to allocate a pair of registers to the symbol.
888 bool tryAllocatingRegPair(symbol *sym)
891 wassert(sym->nRegs == 2);
892 for ( i = 0 ; i < _nRegs ; i+=2 ) {
893 if ((regsZ80[i].isFree)&&(regsZ80[i+1].isFree)) {
894 regsZ80[i].isFree = 0;
895 sym->regs[0] = ®sZ80[i];
896 regsZ80[i+1].isFree = 0;
897 sym->regs[1] = ®sZ80[i+1];
900 bitVectSetBit(currFunc->regsUsed,i);
902 bitVectSetBit(currFunc->regsUsed,i+1);
904 D(D_ALLOC, ("tryAllocRegPair: succeded for sym %zs\n", sym));
908 D(D_ALLOC, ("tryAllocRegPair: failed on sym %zs\n", sym));
912 /** Serially allocate registers to the variables.
913 This is the main register allocation function. It is called after
916 static void serialRegAssign (eBBlock **ebbs, int count)
921 for (i = 0; i < count ; i++ ) {
925 if (ebbs[i]->noPath &&
926 (ebbs[i]->entryLabel != entryLabel &&
927 ebbs[i]->entryLabel != returnLabel ))
930 /* of all instructions do */
931 for (ic = ebbs[i]->sch ; ic ; ic = ic->next) {
933 /* if this is an ipop that means some live
934 range will have to be assigned again */
935 if (ic->op == IPOP) {
937 reassignLR (IC_LEFT(ic));
940 /* if result is present && is a true symbol */
941 if (IC_RESULT(ic) && ic->op != IFX &&
942 IS_TRUE_SYMOP(IC_RESULT(ic)))
943 OP_SYMBOL(IC_RESULT(ic))->allocreq = 1;
945 /* take away registers from live
946 ranges that end at this instruction */
947 deassignLRs (ic, ebbs[i]) ;
949 /* some don't need registers */
950 /* MLH: removed RESULT and POINTER_SET condition */
952 ic->op == JUMPTABLE ||
958 /* now we need to allocate registers only for the result */
960 symbol *sym = OP_SYMBOL(IC_RESULT(ic));
965 D(D_ALLOC, ("serialRegAssign: in loop on result %zs\n", sym));
967 /* if it does not need or is spilt
968 or is already assigned to registers
969 or will not live beyond this instructions */
972 bitVectBitValue(regAssigned,sym->key) ||
973 sym->liveTo <= ic->seq) {
974 D(D_ALLOC, ("serialRegAssign: wont live long enough.\n"));
978 /* if some liverange has been spilt at the block level
979 and this one live beyond this block then spil this
981 if (blockSpil && sym->liveTo > ebbs[i]->lSeq) {
982 D(D_ALLOC, ("serialRegAssign: \"spilling to be safe.\"\n"));
986 /* if trying to allocate this will cause
987 a spill and there is nothing to spill
988 or this one is rematerializable then
990 willCS = willCauseSpill(sym->nRegs,sym->regType);
991 spillable = computeSpillable(ic);
993 (willCS && bitVectIsZero(spillable) ) ) {
995 D(D_ALLOC, ("serialRegAssign: \"remat spill\"\n"));
1001 /* if it has a spillocation & is used less than
1002 all other live ranges then spill this */
1003 if ( willCS && sym->usl.spillLoc ) {
1006 leastUsedLR(liveRangesWith (spillable ,
1011 leastUsed->used > sym->used) {
1017 /* else we assign registers to it */
1018 regAssigned = bitVectSetBit(regAssigned,sym->key);
1020 /* Special case: Try to fit into a reg pair if
1022 D(D_ALLOC, ("serialRegAssign: actually allocing regs!\n"));
1023 if ((sym->nRegs == 2)&&tryAllocatingRegPair(sym)) {
1026 for (j = 0 ; j < sym->nRegs ;j++ ) {
1027 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1029 /* if the allocation falied which means
1030 this was spilt then break */
1031 if (!sym->regs[j]) {
1036 /* if it shares registers with operands make sure
1037 that they are in the same position */
1038 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1039 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1040 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1041 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1042 /* do the same for the right operand */
1043 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1044 OP_SYMBOL(IC_RIGHT(ic))->nRegs && ic->op != '=')
1045 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1046 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1053 /*-----------------------------------------------------------------*/
1054 /* rUmaskForOp :- returns register mask for an operand */
1055 /*-----------------------------------------------------------------*/
1056 bitVect *rUmaskForOp (operand *op)
1062 /* only temporaries are assigned registers */
1066 sym = OP_SYMBOL(op);
1068 /* if spilt or no registers assigned to it
1070 if (sym->isspilt || !sym->nRegs)
1073 rumask = newBitVect(_nRegs);
1075 for (j = 0; j < sym->nRegs; j++) {
1076 rumask = bitVectSetBit(rumask, sym->regs[j]->rIdx);
1082 /** Returns bit vector of registers used in iCode.
1084 bitVect *regsUsedIniCode (iCode *ic)
1086 bitVect *rmask = newBitVect(_nRegs);
1088 /* do the special cases first */
1089 if (ic->op == IFX ) {
1090 rmask = bitVectUnion(rmask,
1091 rUmaskForOp(IC_COND(ic)));
1095 /* for the jumptable */
1096 if (ic->op == JUMPTABLE) {
1097 rmask = bitVectUnion(rmask,
1098 rUmaskForOp(IC_JTCOND(ic)));
1103 /* of all other cases */
1105 rmask = bitVectUnion(rmask,
1106 rUmaskForOp(IC_LEFT(ic)));
1110 rmask = bitVectUnion(rmask,
1111 rUmaskForOp(IC_RIGHT(ic)));
1114 rmask = bitVectUnion(rmask,
1115 rUmaskForOp(IC_RESULT(ic)));
1121 /** For each instruction will determine the regsUsed.
1123 static void createRegMask (eBBlock **ebbs, int count)
1127 /* for all blocks */
1128 for (i = 0; i < count ; i++ ) {
1131 if ( ebbs[i]->noPath &&
1132 ( ebbs[i]->entryLabel != entryLabel &&
1133 ebbs[i]->entryLabel != returnLabel ))
1136 /* for all instructions */
1137 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1141 if (SKIP_IC2(ic) || !ic->rlive)
1144 /* first mark the registers used in this
1146 ic->rUsed = regsUsedIniCode(ic);
1147 funcrUsed = bitVectUnion(funcrUsed,ic->rUsed);
1149 /* now create the register mask for those
1150 registers that are in use : this is a
1151 super set of ic->rUsed */
1152 ic->rMask = newBitVect(_nRegs+1);
1154 /* for all live Ranges alive at this point */
1155 for (j = 1; j < ic->rlive->size; j++ ) {
1159 /* if not alive then continue */
1160 if (!bitVectBitValue(ic->rlive,j))
1163 /* find the live range we are interested in */
1164 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1165 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1166 "createRegMask cannot find live range");
1170 /* if no register assigned to it */
1171 if (!sym->nRegs || sym->isspilt)
1174 /* for all the registers allocated to it */
1175 for (k = 0 ; k < sym->nRegs ;k++)
1178 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1184 /** Returns the rematerialized string for a remat var.
1186 char *rematStr (symbol *sym)
1189 iCode *ic = sym->rematiCode;
1193 /* if plus or minus print the right hand side */
1194 if (ic->op == '+' || ic->op == '-') {
1195 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1198 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1201 /* we reached the end */
1202 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1209 /*-----------------------------------------------------------------*/
1210 /* regTypeNum - computes the type & number of registers required */
1211 /*-----------------------------------------------------------------*/
1212 static void regTypeNum (void)
1217 /* for each live range do */
1218 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1219 sym = hTabNextItem(liveRanges,&k)) {
1221 /* if used zero times then no registers needed */
1222 if ((sym->liveTo - sym->liveFrom) == 0)
1225 D(D_ALLOC, ("regTypeNum: loop on sym %zs\n", sym));
1227 /* if the live range is a temporary */
1230 /* if the type is marked as a conditional */
1231 if (sym->regType == REG_CND)
1234 /* if used in return only then we don't
1236 if (sym->ruonly || sym->accuse) {
1237 if (IS_AGGREGATE(sym->type) || sym->isptr)
1238 sym->type = aggrToPtr(sym->type,FALSE);
1242 /* if not then we require registers */
1243 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1244 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1245 getSize(sym->type));
1247 D(D_ALLOC, ("regTypeNum: setup to assign regs sym %zs\n", sym));
1249 if (sym->nRegs > 4) {
1250 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1251 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1254 /* determine the type of register required */
1255 /* Always general purpose */
1256 sym->regType = REG_GPR ;
1259 /* for the first run we don't provide */
1260 /* registers for true symbols we will */
1261 /* see how things go */
1267 /** Mark all registers as free.
1269 static void freeAllRegs()
1273 D(D_ALLOC, ("freeAllRegs: running.\n"));
1275 for (i=0;i< _nRegs;i++ )
1276 regsZ80[i].isFree = 1;
1279 /*-----------------------------------------------------------------*/
1280 /* deallocStackSpil - this will set the stack pointer back */
1281 /*-----------------------------------------------------------------*/
1282 DEFSETFUNC(deallocStackSpil)
1290 /** Register reduction for assignment.
1292 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1296 D(D_ALLOC, ("packRegsForAssing: running on ic %zi\n", ic));
1299 /* !IS_TRUE_SYMOP(IC_RESULT(ic)) ||*/
1300 !IS_ITEMP(IC_RIGHT(ic)) ||
1301 OP_LIVETO(IC_RIGHT(ic)) > ic->seq ||
1302 OP_SYMBOL(IC_RIGHT(ic))->isind)
1306 /* if the true symbol is defined in far space or on stack
1307 then we should not since this will increase register pressure */
1308 if (isOperandInFarSpace(IC_RESULT(ic))) {
1309 if ((dic = farSpacePackable(ic)))
1316 /* find the definition of iTempNN scanning backwards if we find a
1317 a use of the true symbol in before we find the definition then
1319 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1320 /* if there is a function call and this is
1321 a parameter & not my parameter then don't pack it */
1322 if ( (dic->op == CALL || dic->op == PCALL) &&
1323 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1324 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1332 if (IS_SYMOP(IC_RESULT(dic)) &&
1333 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1337 if (IS_SYMOP(IC_RIGHT(dic)) &&
1338 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1339 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1344 if (IS_SYMOP(IC_LEFT(dic)) &&
1345 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1346 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1351 if (POINTER_SET(dic) &&
1352 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1360 return 0 ; /* did not find */
1362 /* if the result is on stack or iaccess then it must be
1363 the same atleast one of the operands */
1364 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1365 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1367 /* the operation has only one symbol
1368 operator then we can pack */
1369 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1370 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1373 if (!((IC_LEFT(dic) &&
1374 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1376 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1380 /* found the definition */
1381 /* replace the result with the result of */
1382 /* this assignment and remove this assignment */
1383 IC_RESULT(dic) = IC_RESULT(ic) ;
1385 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1386 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1388 /* delete from liverange table also
1389 delete from all the points inbetween and the new
1391 for ( sic = dic; sic != ic ; sic = sic->next ) {
1392 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1393 if (IS_ITEMP(IC_RESULT(dic)))
1394 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1397 remiCodeFromeBBlock(ebp,ic);
1402 /** Scanning backwards looks for first assig found.
1404 iCode *findAssignToSym (operand *op,iCode *ic)
1408 for (dic = ic->prev ; dic ; dic = dic->prev) {
1410 /* if definition by assignment */
1411 if (dic->op == '=' &&
1412 !POINTER_SET(dic) &&
1413 IC_RESULT(dic)->key == op->key)
1414 /* && IS_TRUE_SYMOP(IC_RIGHT(dic))*/
1417 /* we are interested only if defined in far space */
1418 /* or in stack space in case of + & - */
1420 /* if assigned to a non-symbol then return
1422 if (!IS_SYMOP(IC_RIGHT(dic)))
1425 /* if the symbol is in far space then
1427 if (isOperandInFarSpace(IC_RIGHT(dic)))
1430 /* for + & - operations make sure that
1431 if it is on the stack it is the same
1432 as one of the three operands */
1433 if ((ic->op == '+' || ic->op == '-') &&
1434 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1436 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1437 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1438 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1446 /* if we find an usage then we cannot delete it */
1447 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1450 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1453 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1457 /* now make sure that the right side of dic
1458 is not defined between ic & dic */
1460 iCode *sic = dic->next ;
1462 for (; sic != ic ; sic = sic->next)
1463 if (IC_RESULT(sic) &&
1464 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1473 /*-----------------------------------------------------------------*/
1474 /* packRegsForSupport :- reduce some registers for support calls */
1475 /*-----------------------------------------------------------------*/
1476 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1479 /* for the left & right operand :- look to see if the
1480 left was assigned a true symbol in far space in that
1481 case replace them */
1482 D(D_ALLOC, ("packRegsForSupport: running on ic %zi\n", ic));
1484 if (IS_ITEMP(IC_LEFT(ic)) &&
1485 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1486 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1492 /* found it we need to remove it from the
1494 for ( sic = dic; sic != ic ; sic = sic->next )
1495 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1497 IC_LEFT(ic)->operand.symOperand =
1498 IC_RIGHT(dic)->operand.symOperand;
1499 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1500 remiCodeFromeBBlock(ebp,dic);
1504 /* do the same for the right operand */
1507 IS_ITEMP(IC_RIGHT(ic)) &&
1508 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1509 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1515 /* found it we need to remove it from the block */
1516 for ( sic = dic; sic != ic ; sic = sic->next )
1517 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1519 IC_RIGHT(ic)->operand.symOperand =
1520 IC_RIGHT(dic)->operand.symOperand;
1521 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1523 remiCodeFromeBBlock(ebp,dic);
1530 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1532 /** Will reduce some registers for single use.
1534 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1539 D(D_ALLOC, ("packRegsForOneUse: running on ic %zi\n", ic));
1541 /* if returning a literal then do nothing */
1545 /* only upto 2 bytes since we cannot predict
1546 the usage of b, & acc */
1547 if (getSize(operandType(op)) > 2 &&
1552 /* this routine will mark the a symbol as used in one
1553 instruction use only && if the defintion is local
1554 (ie. within the basic block) && has only one definition &&
1555 that definiion is either a return value from a
1556 function or does not contain any variables in
1558 uses = bitVectCopy(OP_USES(op));
1559 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1560 if (!bitVectIsZero(uses)) /* has other uses */
1563 /* if it has only one defintion */
1564 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1565 return NULL ; /* has more than one definition */
1567 /* get the that definition */
1569 hTabItemWithKey(iCodehTab,
1570 bitVectFirstBit(OP_DEFS(op)))))
1573 /* found the definition now check if it is local */
1574 if (dic->seq < ebp->fSeq ||
1575 dic->seq > ebp->lSeq)
1576 return NULL ; /* non-local */
1578 /* now check if it is the return from a function call */
1579 if (dic->op == CALL || dic->op == PCALL ) {
1580 if (ic->op != SEND && ic->op != RETURN) {
1581 OP_SYMBOL(op)->ruonly = 1;
1587 /* otherwise check that the definition does
1588 not contain any symbols in far space */
1589 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1590 isOperandInFarSpace(IC_RIGHT(dic)) ||
1591 IS_OP_RUONLY(IC_LEFT(ic)) ||
1592 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1596 /* if pointer set then make sure the pointer is one byte */
1597 if (POINTER_SET(dic))
1600 if (POINTER_GET(dic))
1605 /* also make sure the intervenening instructions
1606 don't have any thing in far space */
1607 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1608 /* if there is an intervening function call then no */
1609 if (dic->op == CALL || dic->op == PCALL)
1611 /* if pointer set then make sure the pointer
1613 if (POINTER_SET(dic))
1616 if (POINTER_GET(dic))
1619 /* if address of & the result is remat the okay */
1620 if (dic->op == ADDRESS_OF &&
1621 OP_SYMBOL(IC_RESULT(dic))->remat)
1624 /* if left or right or result is in far space */
1625 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1626 isOperandInFarSpace(IC_RIGHT(dic)) ||
1627 isOperandInFarSpace(IC_RESULT(dic)) ||
1628 IS_OP_RUONLY(IC_LEFT(dic)) ||
1629 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1630 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1635 OP_SYMBOL(op)->ruonly = 1;
1639 /*-----------------------------------------------------------------*/
1640 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1641 /*-----------------------------------------------------------------*/
1642 static bool isBitwiseOptimizable (iCode *ic)
1644 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1646 /* bitwise operations are considered optimizable
1647 under the following conditions (Jean-Louis VERN)
1659 if (IS_LITERAL(rtype))
1665 Certian assignments involving pointers can be temporarly stored
1676 /** Pack registers for acc use.
1677 When the result of this operation is small and short lived it may
1678 be able to be stored in the accumelator.
1680 static void packRegsForAccUse (iCode *ic)
1684 /* if + or - then it has to be one byte result */
1685 if ((ic->op == '+' || ic->op == '-')
1686 && getSize(operandType(IC_RESULT(ic))) > 1)
1689 /* if shift operation make sure right side is not a literal */
1690 if (ic->op == RIGHT_OP &&
1691 (isOperandLiteral(IC_RIGHT(ic)) ||
1692 getSize(operandType(IC_RESULT(ic))) > 1))
1695 if (ic->op == LEFT_OP &&
1696 ( isOperandLiteral(IC_RIGHT(ic)) ||
1697 getSize(operandType(IC_RESULT(ic))) > 1))
1700 /* has only one definition */
1701 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1704 /* has only one use */
1705 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1708 /* and the usage immediately follows this iCode */
1709 if (!(uic = hTabItemWithKey(iCodehTab,
1710 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1713 if (ic->next != uic)
1716 /* if it is a conditional branch then we definitely can */
1717 if (uic->op == IFX )
1720 if ( uic->op == JUMPTABLE )
1724 /* if the usage is not is an assignment or an
1725 arithmetic / bitwise / shift operation then not */
1726 if (POINTER_SET(uic) &&
1727 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1731 if (uic->op != '=' &&
1732 !IS_ARITHMETIC_OP(uic) &&
1733 !IS_BITWISE_OP(uic) &&
1734 uic->op != LEFT_OP &&
1735 uic->op != RIGHT_OP )
1738 /* if used in ^ operation then make sure right is not a
1740 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1743 /* if shift operation make sure right side is not a literal */
1744 if (uic->op == RIGHT_OP &&
1745 ( isOperandLiteral(IC_RIGHT(uic)) ||
1746 getSize(operandType(IC_RESULT(uic))) > 1))
1749 if (uic->op == LEFT_OP &&
1750 ( isOperandLiteral(IC_RIGHT(uic)) ||
1751 getSize(operandType(IC_RESULT(uic))) > 1))
1755 /* make sure that the result of this icode is not on the
1756 stack, since acc is used to compute stack offset */
1757 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1758 OP_SYMBOL(IC_RESULT(uic))->onStack)
1763 /* if either one of them in far space then we cannot */
1764 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1765 isOperandInFarSpace(IC_LEFT(uic))) ||
1766 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1767 isOperandInFarSpace(IC_RIGHT(uic))))
1771 /* if the usage has only one operand then we can */
1772 if (IC_LEFT(uic) == NULL ||
1773 IC_RIGHT(uic) == NULL)
1776 /* make sure this is on the left side if not
1777 a '+' since '+' is commutative */
1778 if (ic->op != '+' &&
1779 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1782 /* if one of them is a literal then we can */
1783 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1784 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1785 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1789 /** This is confusing :) Guess for now */
1790 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1791 (IS_ITEMP(IC_RIGHT(uic)) ||
1792 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
1795 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1796 (IS_ITEMP(IC_LEFT(uic)) ||
1797 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
1801 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1804 bool opPreservesA(iCode *ic, iCode *uic)
1806 /* if it is a conditional branch then we definitely can */
1807 if (uic->op == IFX )
1810 if ( uic->op == JUMPTABLE )
1813 /* if the usage has only one operand then we can */
1814 /* PENDING: check */
1815 if (IC_LEFT(uic) == NULL ||
1816 IC_RIGHT(uic) == NULL)
1819 /* PENDING: check this rule */
1820 if (getSize(operandType(IC_RESULT(uic))) > 1) {
1826 !IS_ARITHMETIC_OP(uic) (sub requires A)
1830 !IS_BITWISE_OP(uic) &&
1833 !POINTER_GET(uic) &&
1835 uic->op != LEFT_OP &&
1836 uic->op != RIGHT_OP &&*/
1843 if (!IC_LEFT(uic) || !IC_RESULT(ic))
1846 /** This is confusing :) Guess for now */
1847 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1848 (IS_ITEMP(IC_RIGHT(uic)) ||
1849 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
1852 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1853 (IS_ITEMP(IC_LEFT(uic)) ||
1854 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
1860 /** Pack registers for acc use.
1861 When the result of this operation is small and short lived it may
1862 be able to be stored in the accumelator.
1864 Note that the 'A preserving' list is currently emperical :)e
1866 static void packRegsForAccUse2(iCode *ic)
1870 D(D_ALLOC, ("packRegsForAccUse2: running on ic %zi\n", ic));
1872 /* Filter out all but those 'good' commands */
1876 !IS_BITWISE_OP(ic) &&
1883 /* if + or - then it has to be one byte result.
1886 if ((ic->op == '+' || ic->op == '-')
1887 && getSize(operandType(IC_RESULT(ic))) > 1)
1890 /* if shift operation make sure right side is not a literal.
1894 if (ic->op == RIGHT_OP &&
1895 (isOperandLiteral(IC_RIGHT(ic)) ||
1896 getSize(operandType(IC_RESULT(ic))) > 1))
1899 if (ic->op == LEFT_OP &&
1900 ( isOperandLiteral(IC_RIGHT(ic)) ||
1901 getSize(operandType(IC_RESULT(ic))) > 1))
1905 /* has only one definition */
1906 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1) {
1910 /* Right. We may be able to propagate it through if:
1911 For each in the chain of uses the intermediate is OK.
1913 /* Get next with 'uses result' bit on
1914 If this->next == next
1915 Validate use of next
1916 If OK, increase count
1918 /* and the usage immediately follows this iCode */
1919 if (!(uic = hTabItemWithKey(iCodehTab,
1920 bitVectFirstBit(OP_USES(IC_RESULT(ic)))))) {
1925 /* Create a copy of the OP_USES bit vect */
1926 bitVect *uses = bitVectCopy(OP_USES(IC_RESULT(ic)));
1928 iCode *scan = ic, *next;
1931 setBit = bitVectFirstBit(uses);
1932 next = hTabItemWithKey(iCodehTab, setBit);
1933 if (scan->next == next) {
1934 bitVectUnSetBit(uses, setBit);
1935 /* Still contigous. */
1936 if (!opPreservesA(ic, next)) {
1944 } while (!bitVectIsZero(uses));
1945 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1949 /* OLD CODE FOLLOWS */
1950 /* if it is a conditional branch then we definitely can
1954 if (uic->op == IFX )
1958 if ( uic->op == JUMPTABLE )
1962 /* if the usage is not is an assignment or an
1963 arithmetic / bitwise / shift operation then not.
1964 MLH: Pending: Invalid. Our pointer sets are always peechy.
1967 if (POINTER_SET(uic) &&
1968 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1) {
1969 printf("e5 %u\n", getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)));
1975 if (uic->op != '=' &&
1976 !IS_ARITHMETIC_OP(uic) &&
1977 !IS_BITWISE_OP(uic) &&
1978 uic->op != LEFT_OP &&
1979 uic->op != RIGHT_OP ) {
1984 /* if used in ^ operation then make sure right is not a
1986 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1989 /* if shift operation make sure right side is not a literal */
1990 if (uic->op == RIGHT_OP &&
1991 ( isOperandLiteral(IC_RIGHT(uic)) ||
1992 getSize(operandType(IC_RESULT(uic))) > 1))
1995 if (uic->op == LEFT_OP &&
1996 ( isOperandLiteral(IC_RIGHT(uic)) ||
1997 getSize(operandType(IC_RESULT(uic))) > 1))
2001 /* make sure that the result of this icode is not on the
2002 stack, since acc is used to compute stack offset */
2003 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
2004 OP_SYMBOL(IC_RESULT(uic))->onStack)
2009 /* if either one of them in far space then we cannot */
2010 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
2011 isOperandInFarSpace(IC_LEFT(uic))) ||
2012 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
2013 isOperandInFarSpace(IC_RIGHT(uic))))
2017 /* if the usage has only one operand then we can */
2018 if (IC_LEFT(uic) == NULL ||
2019 IC_RIGHT(uic) == NULL)
2022 /* make sure this is on the left side if not
2023 a '+' since '+' is commutative */
2024 if (ic->op != '+' &&
2025 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
2028 /* if one of them is a literal then we can */
2029 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
2030 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
2031 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2035 /** This is confusing :) Guess for now */
2036 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
2037 (IS_ITEMP(IC_RIGHT(uic)) ||
2038 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
2041 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
2042 (IS_ITEMP(IC_LEFT(uic)) ||
2043 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
2047 printf("acc ok!\n");
2048 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2051 /** Does some transformations to reduce register pressure.
2053 static void packRegisters (eBBlock *ebp)
2058 D(D_ALLOC, ("packRegisters: entered.\n"));
2060 while (1 && !DISABLE_PACK_ASSIGN) {
2062 /* look for assignments of the form */
2063 /* iTempNN = TRueSym (someoperation) SomeOperand */
2065 /* TrueSym := iTempNN:1 */
2066 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2067 /* find assignment of the form TrueSym := iTempNN:1 */
2068 if (ic->op == '=' && !POINTER_SET(ic))
2069 change += packRegsForAssign(ic,ebp);
2075 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2076 /* Safe: address of a true sym is always constant. */
2077 /* if this is an itemp & result of a address of a true sym
2078 then mark this as rematerialisable */
2080 D(D_ALLOC, ("packRegisters: looping on ic %zi\n", ic));
2082 if (ic->op == ADDRESS_OF &&
2083 IS_ITEMP(IC_RESULT(ic)) &&
2084 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2085 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2086 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2088 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2089 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2090 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2093 /* Safe: just propagates the remat flag */
2094 /* if straight assignment then carry remat flag if this is the
2096 if (ic->op == '=' &&
2098 IS_SYMOP(IC_RIGHT(ic)) &&
2099 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2100 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2102 OP_SYMBOL(IC_RESULT(ic))->remat =
2103 OP_SYMBOL(IC_RIGHT(ic))->remat;
2104 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2105 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2108 /* if the condition of an if instruction is defined in the
2109 previous instruction then mark the itemp as a conditional */
2110 if ((IS_CONDITIONAL(ic) ||
2111 ( ( ic->op == BITWISEAND ||
2114 isBitwiseOptimizable(ic))) &&
2115 ic->next && ic->next->op == IFX &&
2116 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2117 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2119 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2124 /* reduce for support function calls */
2125 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2126 packRegsForSupport(ic,ebp);
2130 /* some cases the redundant moves can
2131 can be eliminated for return statements */
2132 if ((ic->op == RETURN || ic->op == SEND) &&
2133 !isOperandInFarSpace(IC_LEFT(ic)) &&
2135 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2137 /* if pointer set & left has a size more than
2138 one and right is not in far space */
2139 if (POINTER_SET(ic) &&
2140 /* MLH: no such thing.
2141 !isOperandInFarSpace(IC_RIGHT(ic)) && */
2142 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2143 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2144 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2146 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2148 /* if pointer get */
2149 if (POINTER_GET(ic) &&
2150 /* MLH: dont have far space
2151 !isOperandInFarSpace(IC_RESULT(ic))&& */
2152 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2153 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2154 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2155 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2156 /* pack registers for accumulator use, when the result of an
2157 arithmetic or bit wise operation has only one use, that use is
2158 immediately following the defintion and the using iCode has
2159 only one operand or has two operands but one is literal & the
2160 result of that operation is not on stack then we can leave the
2161 result of this operation in acc:b combination */
2163 if ((IS_ARITHMETIC_OP(ic)
2164 || IS_BITWISE_OP(ic)
2165 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2167 IS_ITEMP(IC_RESULT(ic)) &&
2168 getSize(operandType(IC_RESULT(ic))) <= 2)
2169 packRegsForAccUse (ic);
2171 if (!DISABLE_PACK_ACC && IS_ITEMP(IC_RESULT(ic)) &&
2172 getSize(operandType(IC_RESULT(ic))) == 1)
2173 packRegsForAccUse2(ic);
2178 /*-----------------------------------------------------------------*/
2179 /* assignRegisters - assigns registers to each live range as need */
2180 /*-----------------------------------------------------------------*/
2181 void z80_assignRegisters (eBBlock **ebbs, int count)
2186 D(D_ALLOC, ("\n-> z80_assignRegisters: entered.\n"));
2188 setToNull((void *)&funcrUsed);
2189 stackExtend = dataExtend = 0;
2192 /* DE is required for the code gen. */
2193 _nRegs = GBZ80_MAX_REGS;
2194 regsZ80 = _gbz80_regs;
2197 _nRegs = Z80_MAX_REGS;
2198 regsZ80 = _z80_regs;
2201 /* change assignments this will remove some
2202 live ranges reducing some register pressure */
2203 for (i = 0 ; i < count ;i++ )
2204 packRegisters (ebbs[i]);
2206 if (options.dump_pack)
2207 dumpEbbsToFileExt(".dumppack",ebbs,count);
2209 /* first determine for each live range the number of
2210 registers & the type of registers required for each */
2213 /* and serially allocate registers */
2214 serialRegAssign(ebbs,count);
2216 /* if stack was extended then tell the user */
2218 /* werror(W_TOOMANY_SPILS,"stack", */
2219 /* stackExtend,currFunc->name,""); */
2224 /* werror(W_TOOMANY_SPILS,"data space", */
2225 /* dataExtend,currFunc->name,""); */
2229 if (options.dump_rassgn)
2230 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2232 /* after that create the register mask
2233 for each of the instruction */
2234 createRegMask (ebbs,count);
2236 /* now get back the chain */
2237 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2239 /* redo that offsets for stacked automatic variables */
2240 redoStackOffsets ();
2244 /* free up any stackSpil locations allocated */
2245 applyToSet(stackSpil,deallocStackSpil);
2247 setToNull((void **)&stackSpil);
2248 setToNull((void **)&spiltSet);
2249 /* mark all registers as free */