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
50 DISABLE_PACK_ASSIGN = 0,
57 #define D(_a, _s) if (_a) { printf _s; fflush(stdout); }
62 /*-----------------------------------------------------------------*/
63 /* At this point we start getting processor specific although */
64 /* some routines are non-processor specific & can be reused when */
65 /* targetting other processors. The decision for this will have */
66 /* to be made on a routine by routine basis */
67 /* routines used to pack registers are most definitely not reusable*/
68 /* since the pack the registers depending strictly on the MCU */
69 /*-----------------------------------------------------------------*/
71 bitVect *spiltSet = NULL ;
72 set *stackSpil = NULL;
73 bitVect *regAssigned = NULL;
76 extern void genZ80Code(iCode *);
77 bitVect *funcrUsed = NULL; /* registers used in a function */
82 /** Set to help debug register pressure related problems */
83 #define DEBUG_FAKE_EXTRA_REGS 0
85 static regs _gbz80_regs[] = {
86 { REG_GPR, C_IDX , "c", 1 },
87 { REG_GPR, B_IDX , "b", 1 },
88 { REG_CND, CND_IDX, "c", 1}
91 static regs _z80_regs[] = {
92 { REG_GPR, C_IDX , "c", 1 },
93 { REG_GPR, B_IDX , "b", 1 },
94 { REG_GPR, E_IDX , "e", 1 },
95 { REG_GPR, D_IDX , "d", 1 },
96 /* { REG_GPR, L_IDX , "l", 1 },
97 { REG_GPR, H_IDX , "h", 1 },*/
98 #if DEBUG_FAKE_EXTRA_REGS
99 { REG_GPR, M_IDX , "m", 1 },
100 { REG_GPR, N_IDX , "n", 1 },
101 { REG_GPR, O_IDX , "o", 1 },
102 { REG_GPR, P_IDX , "p", 1 },
103 { REG_GPR, Q_IDX , "q", 1 },
104 { REG_GPR, R_IDX , "r", 1 },
105 { REG_GPR, S_IDX , "s", 1 },
106 { REG_GPR, T_IDX , "t", 1 },
108 { REG_CND, CND_IDX, "c", 1}
113 /** Number of usable registers (all but C) */
114 #define Z80_MAX_REGS ((sizeof(_z80_regs)/sizeof(_z80_regs[0]))-1)
115 #define GBZ80_MAX_REGS ((sizeof(_gbz80_regs)/sizeof(_gbz80_regs[0]))-1)
117 static void spillThis (symbol *);
119 /** Allocates register of given type.
120 'type' is not used on the z80 version. It was used to select
121 between pointer and general purpose registers on the mcs51 version.
123 @return Pointer to the newly allocated register.
125 static regs *allocReg (short type)
129 for ( i = 0 ; i < _nRegs ; i++ ) {
130 /* For now we allocate from any free */
131 if (regsZ80[i].isFree ) {
132 regsZ80[i].isFree = 0;
135 bitVectSetBit(currFunc->regsUsed,i);
136 D(D_ALLOC, ("allocReg: alloced %zr\n", ®sZ80[i]));
140 D(D_ALLOC, ("allocReg: No free.\n"));
144 /** Returns pointer to register wit index number
146 regs *regWithIdx (int idx)
150 for (i=0;i < _nRegs;i++)
151 if (regsZ80[i].rIdx == idx)
154 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
155 "regWithIdx not found");
159 /** Frees a register.
161 static void freeReg (regs *reg)
163 wassert(!reg->isFree);
165 D(D_ALLOC, ("freeReg: freed %zr\n", reg));
169 /** Returns number of free registers.
171 static int nFreeRegs (int type)
176 for (i = 0 ; i < _nRegs; i++ ) {
177 /* For now only one reg type */
178 if (regsZ80[i].isFree)
184 /** Free registers with type.
186 static int nfreeRegsType (int type)
189 if (type == REG_PTR) {
190 if ((nfr = nFreeRegs(type)) == 0)
191 return nFreeRegs(REG_GPR);
194 return nFreeRegs(type);
199 /*-----------------------------------------------------------------*/
200 /* allDefsOutOfRange - all definitions are out of a range */
201 /*-----------------------------------------------------------------*/
202 static bool allDefsOutOfRange (bitVect *defs,int fseq, int toseq)
209 for ( i = 0 ;i < defs->size ; i++ ) {
212 if (bitVectBitValue(defs,i) &&
213 (ic = hTabItemWithKey(iCodehTab,i)) &&
214 ( ic->seq >= fseq && ic->seq <= toseq))
224 /*-----------------------------------------------------------------*/
225 /* computeSpillable - given a point find the spillable live ranges */
226 /*-----------------------------------------------------------------*/
227 static bitVect *computeSpillable (iCode *ic)
231 /* spillable live ranges are those that are live at this
232 point . the following categories need to be subtracted
234 a) - those that are already spilt
235 b) - if being used by this one
236 c) - defined by this one */
238 spillable = bitVectCopy(ic->rlive);
240 bitVectCplAnd(spillable,spiltSet); /* those already spilt */
242 bitVectCplAnd(spillable,ic->uses); /* used in this one */
243 bitVectUnSetBit(spillable,ic->defKey);
244 spillable = bitVectIntersect(spillable,regAssigned);
249 /*-----------------------------------------------------------------*/
250 /* noSpilLoc - return true if a variable has no spil location */
251 /*-----------------------------------------------------------------*/
252 static int noSpilLoc (symbol *sym, eBBlock *ebp,iCode *ic)
254 return (sym->usl.spillLoc ? 0 : 1);
257 /*-----------------------------------------------------------------*/
258 /* hasSpilLoc - will return 1 if the symbol has spil location */
259 /*-----------------------------------------------------------------*/
260 static int hasSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
262 return (sym->usl.spillLoc ? 1 : 0);
265 /** Will return 1 if the remat flag is set.
266 A symbol is rematerialisable if it doesnt need to be allocated
267 into registers at creation as it can be re-created at any time -
268 i.e. it's constant in some way.
270 static int rematable (symbol *sym, eBBlock *ebp, iCode *ic)
275 /*-----------------------------------------------------------------*/
276 /* allLRs - return true for all */
277 /*-----------------------------------------------------------------*/
278 static int allLRs (symbol *sym, eBBlock *ebp, iCode *ic)
283 /*-----------------------------------------------------------------*/
284 /* liveRangesWith - applies function to a given set of live range */
285 /*-----------------------------------------------------------------*/
286 set *liveRangesWith (bitVect *lrs, int (func)(symbol *,eBBlock *, iCode *),
287 eBBlock *ebp, iCode *ic)
292 if (!lrs || !lrs->size)
295 for ( i = 1 ; i < lrs->size ; i++ ) {
297 if (!bitVectBitValue(lrs,i))
300 /* if we don't find it in the live range
301 hash table we are in serious trouble */
302 if (!(sym = hTabItemWithKey(liveRanges,i))) {
303 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
304 "liveRangesWith could not find liveRange");
308 if (func(sym,ebp,ic) && bitVectBitValue(regAssigned,sym->key))
309 addSetHead(&rset,sym);
316 /*-----------------------------------------------------------------*/
317 /* leastUsedLR - given a set determines which is the least used */
318 /*-----------------------------------------------------------------*/
319 symbol *leastUsedLR (set *sset)
321 symbol *sym = NULL, *lsym = NULL ;
323 sym = lsym = setFirstItem(sset);
328 for (; lsym; lsym = setNextItem(sset)) {
330 /* if usage is the same then prefer
331 the spill the smaller of the two */
332 if ( lsym->used == sym->used )
333 if (getSize(lsym->type) < getSize(sym->type))
337 if (lsym->used < sym->used )
342 setToNull((void **)&sset);
347 /*-----------------------------------------------------------------*/
348 /* noOverLap - will iterate through the list looking for over lap */
349 /*-----------------------------------------------------------------*/
350 static int noOverLap (set *itmpStack, symbol *fsym)
354 for (sym = setFirstItem(itmpStack); sym;
355 sym = setNextItem(itmpStack)) {
356 if (sym->liveTo > fsym->liveFrom )
363 /*-----------------------------------------------------------------*/
364 /* isFree - will return 1 if the a free spil location is found */
365 /*-----------------------------------------------------------------*/
369 V_ARG(symbol **,sloc);
370 V_ARG(symbol *,fsym);
372 /* if already found */
376 /* if it is free && and the itmp assigned to
377 this does not have any overlapping live ranges
378 with the one currently being assigned and
379 the size can be accomodated */
381 noOverLap(sym->usl.itmpStack,fsym) &&
382 getSize(sym->type) >= getSize(fsym->type)) {
390 /*-----------------------------------------------------------------*/
391 /* createStackSpil - create a location on the stack to spil */
392 /*-----------------------------------------------------------------*/
393 symbol *createStackSpil (symbol *sym)
397 D(D_ALLOC, ("createStackSpil: for sym %zs\n", sym));
399 /* first go try and find a free one that is already
400 existing on the stack */
401 if (applyToSet(stackSpil,isFree,&sloc, sym)) {
402 /* found a free one : just update & return */
403 sym->usl.spillLoc = sloc;
406 addSetHead(&sloc->usl.itmpStack,sym);
407 D(D_ALLOC, ("createStackSpil: found existing\n"));
411 /* could not then have to create one , this is the hard part
412 we need to allocate this on the stack : this is really a
413 hack!! but cannot think of anything better at this time */
415 sprintf(buffer,"sloc%d",slocNum++);
416 sloc = newiTemp(buffer);
418 /* set the type to the spilling symbol */
419 sloc->type = copyLinkChain(sym->type);
420 sloc->etype = getSpec(sloc->type);
421 SPEC_SCLS(sloc->etype) = S_AUTO ;
423 /* we don't allow it to be allocated`
424 onto the external stack since : so we
425 temporarily turn it off ; we also
426 turn off memory model to prevent
427 the spil from going to the external storage
428 and turn off overlaying
432 sloc->isref = 1; /* to prevent compiler warning */
434 /* if it is on the stack then update the stack */
435 if (IN_STACK(sloc->etype)) {
436 currFunc->stack += getSize(sloc->type);
437 stackExtend += getSize(sloc->type);
439 dataExtend += getSize(sloc->type);
441 /* add it to the stackSpil set */
442 addSetHead(&stackSpil,sloc);
443 sym->usl.spillLoc = sloc;
446 /* add it to the set of itempStack set
447 of the spill location */
448 addSetHead(&sloc->usl.itmpStack,sym);
450 D(D_ALLOC, ("createStackSpil: created new\n"));
454 /*-----------------------------------------------------------------*/
455 /* isSpiltOnStack - returns true if the spil location is on stack */
456 /*-----------------------------------------------------------------*/
457 bool isSpiltOnStack (symbol *sym)
467 /* if (sym->stackSpil) */
470 if (!sym->usl.spillLoc)
473 etype = getSpec(sym->usl.spillLoc->type);
480 /*-----------------------------------------------------------------*/
481 /* spillThis - spils a specific operand */
482 /*-----------------------------------------------------------------*/
483 static void spillThis (symbol *sym)
487 D(D_ALLOC, ("spillThis: spilling %zs\n", sym));
489 /* if this is rematerializable or has a spillLocation
490 we are okay, else we need to create a spillLocation
492 if (!(sym->remat || sym->usl.spillLoc))
493 createStackSpil (sym);
495 /* mark it has spilt & put it in the spilt set */
497 spiltSet = bitVectSetBit(spiltSet,sym->key);
499 bitVectUnSetBit(regAssigned,sym->key);
501 for (i = 0 ; i < sym->nRegs ; i++) {
503 freeReg(sym->regs[i]);
508 /* if spilt on stack then free up r0 & r1
509 if they could have been assigned to some
511 if (sym->usl.spillLoc && !sym->remat)
512 sym->usl.spillLoc->allocreq = 1;
516 /** Select a iTemp to spil : rather a simple procedure.
518 symbol *selectSpil (iCode *ic, eBBlock *ebp, symbol *forSym)
520 bitVect *lrcs= NULL ;
524 D(D_ALLOC, ("selectSpil: finding spill for ic %zi\n", ic));
525 /* get the spillable live ranges */
526 lrcs = computeSpillable (ic);
528 /* get all live ranges that are rematerizable */
529 if ((selectS = liveRangesWith(lrcs,rematable,ebp,ic))) {
530 D(D_ALLOC, ("selectSpil: using remat.\n"));
531 /* return the least used of these */
532 return leastUsedLR(selectS);
536 /* get live ranges with spillLocations in direct space */
537 if ((selectS = liveRangesWith(lrcs,directSpilLoc,ebp,ic))) {
538 sym = leastUsedLR(selectS);
539 strcpy(sym->rname,(sym->usl.spillLoc->rname[0] ?
540 sym->usl.spillLoc->rname :
541 sym->usl.spillLoc->name));
543 /* mark it as allocation required */
544 sym->usl.spillLoc->allocreq = 1;
548 /* if the symbol is local to the block then */
549 if (forSym->liveTo < ebp->lSeq ) {
551 /* check if there are any live ranges allocated
552 to registers that are not used in this block */
553 if (!blockSpil && (selectS = liveRangesWith(lrcs,notUsedInBlock,ebp,ic))) {
554 sym = leastUsedLR(selectS);
555 /* if this is not rematerializable */
563 /* check if there are any live ranges that not
564 used in the remainder of the block */
565 if (!blockSpil && (selectS = liveRangesWith(lrcs,notUsedInRemaining,ebp,ic))) {
566 sym = leastUsedLR (selectS);
574 /* find live ranges with spillocation && not used as pointers */
575 if ((selectS = liveRangesWith(lrcs,hasSpilLocnoUptr,ebp,ic))) {
577 sym = leastUsedLR(selectS);
578 /* mark this as allocation required */
579 sym->usl.spillLoc->allocreq = 1;
584 /* find live ranges with spillocation */
585 if ((selectS = liveRangesWith(lrcs,hasSpilLoc,ebp,ic))) {
586 D(D_ALLOC, ("selectSpil: using with spill.\n"));
587 sym = leastUsedLR(selectS);
588 sym->usl.spillLoc->allocreq = 1;
592 /* couldn't find then we need to create a spil
593 location on the stack , for which one? the least
595 if ((selectS = liveRangesWith(lrcs,noSpilLoc,ebp,ic))) {
596 D(D_ALLOC, ("selectSpil: creating new spill.\n"));
597 /* return a created spil location */
598 sym = createStackSpil(leastUsedLR(selectS));
599 sym->usl.spillLoc->allocreq = 1;
603 /* this is an extreme situation we will spill
604 this one : happens very rarely but it does happen */
605 D(D_ALLOC, ("selectSpil: using spillThis.\n"));
606 spillThis ( forSym );
611 /** Spil some variable & mark registers as free.
612 A spill occurs when an iTemp wont fit into the available registers.
614 bool spilSomething (iCode *ic, eBBlock *ebp, symbol *forSym)
619 D(D_ALLOC, ("spilSomething: spilling on ic %zi\n", ic));
621 /* get something we can spil */
622 ssym = selectSpil(ic,ebp,forSym);
624 /* mark it as spilt */
626 spiltSet = bitVectSetBit(spiltSet,ssym->key);
628 /* mark it as not register assigned &
629 take it away from the set */
630 bitVectUnSetBit(regAssigned,ssym->key);
632 /* mark the registers as free */
633 for (i = 0 ; i < ssym->nRegs ;i++ )
635 freeReg(ssym->regs[i]);
637 /* if spilt on stack then free up r0 & r1
638 if they could have been assigned to as gprs */
639 if (!ptrRegReq && isSpiltOnStack(ssym) ) {
641 spillLRWithPtrReg(ssym);
644 /* if this was a block level spil then insert push & pop
645 at the start & end of block respectively */
646 if (ssym->blockSpil) {
647 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
648 /* add push to the start of the block */
649 addiCodeToeBBlock(ebp,nic,( ebp->sch->op == LABEL ?
650 ebp->sch->next : ebp->sch));
651 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
652 /* add pop to the end of the block */
653 addiCodeToeBBlock(ebp,nic,NULL);
656 /* if spilt because not used in the remainder of the
657 block then add a push before this instruction and
658 a pop at the end of the block */
659 if (ssym->remainSpil) {
661 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
662 /* add push just before this instruction */
663 addiCodeToeBBlock(ebp,nic,ic);
665 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
666 /* add pop to the end of the block */
667 addiCodeToeBBlock(ebp,nic,NULL);
671 D(D_ALLOC, ("spilSomething: done.\n"));
679 /** Will try for GPR if not spil.
681 regs *getRegGpr (iCode *ic, eBBlock *ebp,symbol *sym)
685 D(D_ALLOC, ("getRegGpr: on ic %zi\n"));
687 /* try for gpr type */
688 if ((reg = allocReg(REG_GPR))) {
689 D(D_ALLOC, ("getRegGpr: got a reg.\n"));
693 /* we have to spil */
694 if (!spilSomething (ic,ebp,sym)) {
695 D(D_ALLOC, ("getRegGpr: have to spill.\n"));
699 /* this looks like an infinite loop but
700 in really selectSpil will abort */
704 /** Symbol has a given register.
706 static bool symHasReg(symbol *sym,regs *reg)
710 for ( i = 0 ; i < sym->nRegs ; i++)
711 if (sym->regs[i] == reg)
717 /** Check the live to and if they have registers & are not spilt then
718 free up the registers
720 static void deassignLRs (iCode *ic, eBBlock *ebp)
726 for (sym = hTabFirstItem(liveRanges,&k); sym;
727 sym = hTabNextItem(liveRanges,&k)) {
730 /* if it does not end here */
731 if (sym->liveTo > ic->seq )
734 /* if it was spilt on stack then we can
735 mark the stack spil location as free */
737 if (sym->stackSpil) {
738 sym->usl.spillLoc->isFree = 1;
744 if (!bitVectBitValue(regAssigned,sym->key))
747 /* special case check if this is an IFX &
748 the privious one was a pop and the
749 previous one was not spilt then keep track
751 if (ic->op == IFX && ic->prev &&
752 ic->prev->op == IPOP &&
753 !ic->prev->parmPush &&
754 !OP_SYMBOL(IC_LEFT(ic->prev))->isspilt)
755 psym = OP_SYMBOL(IC_LEFT(ic->prev));
757 D(D_ALLOC, ("deassignLRs: in loop on sym %zs", sym));
762 bitVectUnSetBit(regAssigned,sym->key);
764 /* if the result of this one needs registers
765 and does not have it then assign it right
768 ! (SKIP_IC2(ic) || /* not a special icode */
769 ic->op == JUMPTABLE ||
774 (result = OP_SYMBOL(IC_RESULT(ic))) && /* has a result */
775 result->liveTo > ic->seq && /* and will live beyond this */
776 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
777 result->regType == sym->regType && /* same register types */
778 result->nRegs && /* which needs registers */
779 ! result->isspilt && /* and does not already have them */
781 ! bitVectBitValue(regAssigned,result->key) &&
782 /* the number of free regs + number of regs in this LR
783 can accomodate the what result Needs */
784 ((nfreeRegsType(result->regType) +
785 sym->nRegs) >= result->nRegs)
787 for (i = 0 ; i < max(sym->nRegs,result->nRegs) ; i++) {
789 result->regs[i] = sym->regs[i] ;
791 result->regs[i] = getRegGpr (ic,ebp,result);
793 /* if the allocation falied which means
794 this was spilt then break */
795 if (!result->regs[i]) {
802 regAssigned = bitVectSetBit(regAssigned,result->key);
805 /* free the remaining */
806 for (; i < sym->nRegs ; i++) {
808 if (!symHasReg(psym,sym->regs[i]))
809 freeReg(sym->regs[i]);
811 freeReg(sym->regs[i]);
812 // sym->regs[i] = NULL;
819 /** Reassign this to registers.
821 static void reassignLR (operand *op)
823 symbol *sym = OP_SYMBOL(op);
826 D(D_ALLOC, ("reassingLR: on sym %zs\n", sym));
828 /* not spilt any more */
829 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
830 bitVectUnSetBit(spiltSet,sym->key);
832 regAssigned = bitVectSetBit(regAssigned,sym->key);
836 for (i=0;i<sym->nRegs;i++)
837 sym->regs[i]->isFree = 0;
840 /** Determines if allocating will cause a spill.
842 static int willCauseSpill ( int nr, int rt)
844 /* first check if there are any avlb registers
845 of te type required */
846 if (nFreeRegs(0) >= nr)
849 /* it will cause a spil */
853 /** The allocator can allocate same registers to result and operand,
854 if this happens make sure they are in the same position as the operand
855 otherwise chaos results.
857 static void positionRegs (symbol *result, symbol *opsym, int lineno)
859 int count = min(result->nRegs,opsym->nRegs);
860 int i , j = 0, shared = 0;
862 D(D_ALLOC, ("positionRegs: on result %zs opsum %zs line %u\n", result, opsym, lineno));
864 /* if the result has been spilt then cannot share */
869 /* first make sure that they actually share */
870 for ( i = 0 ; i < count; i++ ) {
871 for (j = 0 ; j < count ; j++ ) {
872 if (result->regs[i] == opsym->regs[j] && i !=j) {
880 regs *tmp = result->regs[i];
881 result->regs[i] = result->regs[j];
882 result->regs[j] = tmp;
887 /** Try to allocate a pair of registers to the symbol.
889 bool tryAllocatingRegPair(symbol *sym)
892 wassert(sym->nRegs == 2);
893 for ( i = 0 ; i < _nRegs ; i+=2 ) {
894 if ((regsZ80[i].isFree)&&(regsZ80[i+1].isFree)) {
895 regsZ80[i].isFree = 0;
896 sym->regs[0] = ®sZ80[i];
897 regsZ80[i+1].isFree = 0;
898 sym->regs[1] = ®sZ80[i+1];
901 bitVectSetBit(currFunc->regsUsed,i);
903 bitVectSetBit(currFunc->regsUsed,i+1);
905 D(D_ALLOC, ("tryAllocRegPair: succeded for sym %zs\n", sym));
909 D(D_ALLOC, ("tryAllocRegPair: failed on sym %zs\n", sym));
913 /** Serially allocate registers to the variables.
914 This is the main register allocation function. It is called after
917 static void serialRegAssign (eBBlock **ebbs, int count)
922 for (i = 0; i < count ; i++ ) {
926 if (ebbs[i]->noPath &&
927 (ebbs[i]->entryLabel != entryLabel &&
928 ebbs[i]->entryLabel != returnLabel ))
931 /* of all instructions do */
932 for (ic = ebbs[i]->sch ; ic ; ic = ic->next) {
934 /* if this is an ipop that means some live
935 range will have to be assigned again */
936 if (ic->op == IPOP) {
938 reassignLR (IC_LEFT(ic));
941 /* if result is present && is a true symbol */
942 if (IC_RESULT(ic) && ic->op != IFX &&
943 IS_TRUE_SYMOP(IC_RESULT(ic)))
944 OP_SYMBOL(IC_RESULT(ic))->allocreq = 1;
946 /* take away registers from live
947 ranges that end at this instruction */
948 deassignLRs (ic, ebbs[i]) ;
950 /* some don't need registers */
951 /* MLH: removed RESULT and POINTER_SET condition */
953 ic->op == JUMPTABLE ||
959 /* now we need to allocate registers only for the result */
961 symbol *sym = OP_SYMBOL(IC_RESULT(ic));
966 D(D_ALLOC, ("serialRegAssign: in loop on result %zs\n", sym));
968 /* if it does not need or is spilt
969 or is already assigned to registers
970 or will not live beyond this instructions */
973 bitVectBitValue(regAssigned,sym->key) ||
974 sym->liveTo <= ic->seq) {
975 D(D_ALLOC, ("serialRegAssign: wont live long enough.\n"));
979 /* if some liverange has been spilt at the block level
980 and this one live beyond this block then spil this
982 if (blockSpil && sym->liveTo > ebbs[i]->lSeq) {
983 D(D_ALLOC, ("serialRegAssign: \"spilling to be safe.\"\n"));
987 /* if trying to allocate this will cause
988 a spill and there is nothing to spill
989 or this one is rematerializable then
991 willCS = willCauseSpill(sym->nRegs,sym->regType);
992 spillable = computeSpillable(ic);
994 (willCS && bitVectIsZero(spillable) ) ) {
996 D(D_ALLOC, ("serialRegAssign: \"remat spill\"\n"));
1002 /* if it has a spillocation & is used less than
1003 all other live ranges then spill this */
1004 if ( willCS && sym->usl.spillLoc ) {
1007 leastUsedLR(liveRangesWith (spillable ,
1012 leastUsed->used > sym->used) {
1018 /* else we assign registers to it */
1019 regAssigned = bitVectSetBit(regAssigned,sym->key);
1021 /* Special case: Try to fit into a reg pair if
1023 D(D_ALLOC, ("serialRegAssign: actually allocing regs!\n"));
1024 if ((sym->nRegs == 2)&&tryAllocatingRegPair(sym)) {
1027 for (j = 0 ; j < sym->nRegs ;j++ ) {
1028 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1030 /* if the allocation falied which means
1031 this was spilt then break */
1032 if (!sym->regs[j]) {
1037 /* if it shares registers with operands make sure
1038 that they are in the same position */
1039 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1040 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1041 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1042 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1043 /* do the same for the right operand */
1044 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1045 OP_SYMBOL(IC_RIGHT(ic))->nRegs && ic->op != '=')
1046 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1047 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1054 /*-----------------------------------------------------------------*/
1055 /* rUmaskForOp :- returns register mask for an operand */
1056 /*-----------------------------------------------------------------*/
1057 bitVect *rUmaskForOp (operand *op)
1063 /* only temporaries are assigned registers */
1067 sym = OP_SYMBOL(op);
1069 /* if spilt or no registers assigned to it
1071 if (sym->isspilt || !sym->nRegs)
1074 rumask = newBitVect(_nRegs);
1076 for (j = 0; j < sym->nRegs; j++) {
1077 rumask = bitVectSetBit(rumask, sym->regs[j]->rIdx);
1083 /** Returns bit vector of registers used in iCode.
1085 bitVect *regsUsedIniCode (iCode *ic)
1087 bitVect *rmask = newBitVect(_nRegs);
1089 /* do the special cases first */
1090 if (ic->op == IFX ) {
1091 rmask = bitVectUnion(rmask,
1092 rUmaskForOp(IC_COND(ic)));
1096 /* for the jumptable */
1097 if (ic->op == JUMPTABLE) {
1098 rmask = bitVectUnion(rmask,
1099 rUmaskForOp(IC_JTCOND(ic)));
1104 /* of all other cases */
1106 rmask = bitVectUnion(rmask,
1107 rUmaskForOp(IC_LEFT(ic)));
1111 rmask = bitVectUnion(rmask,
1112 rUmaskForOp(IC_RIGHT(ic)));
1115 rmask = bitVectUnion(rmask,
1116 rUmaskForOp(IC_RESULT(ic)));
1122 /** For each instruction will determine the regsUsed.
1124 static void createRegMask (eBBlock **ebbs, int count)
1128 /* for all blocks */
1129 for (i = 0; i < count ; i++ ) {
1132 if ( ebbs[i]->noPath &&
1133 ( ebbs[i]->entryLabel != entryLabel &&
1134 ebbs[i]->entryLabel != returnLabel ))
1137 /* for all instructions */
1138 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1142 if (SKIP_IC2(ic) || !ic->rlive)
1145 /* first mark the registers used in this
1147 ic->rUsed = regsUsedIniCode(ic);
1148 funcrUsed = bitVectUnion(funcrUsed,ic->rUsed);
1150 /* now create the register mask for those
1151 registers that are in use : this is a
1152 super set of ic->rUsed */
1153 ic->rMask = newBitVect(_nRegs+1);
1155 /* for all live Ranges alive at this point */
1156 for (j = 1; j < ic->rlive->size; j++ ) {
1160 /* if not alive then continue */
1161 if (!bitVectBitValue(ic->rlive,j))
1164 /* find the live range we are interested in */
1165 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1166 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1167 "createRegMask cannot find live range");
1171 /* if no register assigned to it */
1172 if (!sym->nRegs || sym->isspilt)
1175 /* for all the registers allocated to it */
1176 for (k = 0 ; k < sym->nRegs ;k++)
1179 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1185 /** Returns the rematerialized string for a remat var.
1187 char *rematStr (symbol *sym)
1190 iCode *ic = sym->rematiCode;
1194 /* if plus or minus print the right hand side */
1195 if (ic->op == '+' || ic->op == '-') {
1196 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1199 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1202 /* we reached the end */
1203 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1210 /*-----------------------------------------------------------------*/
1211 /* regTypeNum - computes the type & number of registers required */
1212 /*-----------------------------------------------------------------*/
1213 static void regTypeNum (void)
1218 /* for each live range do */
1219 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1220 sym = hTabNextItem(liveRanges,&k)) {
1222 /* if used zero times then no registers needed */
1223 if ((sym->liveTo - sym->liveFrom) == 0)
1226 D(D_ALLOC, ("regTypeNum: loop on sym %zs\n", sym));
1228 /* if the live range is a temporary */
1231 /* if the type is marked as a conditional */
1232 if (sym->regType == REG_CND)
1235 /* if used in return only then we don't
1237 if (sym->ruonly || sym->accuse) {
1238 if (IS_AGGREGATE(sym->type) || sym->isptr)
1239 sym->type = aggrToPtr(sym->type,FALSE);
1243 /* if not then we require registers */
1244 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1245 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1246 getSize(sym->type));
1248 D(D_ALLOC, ("regTypeNum: setup to assign regs sym %zs\n", sym));
1250 if (sym->nRegs > 4) {
1251 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1252 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1255 /* determine the type of register required */
1256 /* Always general purpose */
1257 sym->regType = REG_GPR ;
1260 /* for the first run we don't provide */
1261 /* registers for true symbols we will */
1262 /* see how things go */
1268 /** Mark all registers as free.
1270 static void freeAllRegs()
1274 D(D_ALLOC, ("freeAllRegs: running.\n"));
1276 for (i=0;i< _nRegs;i++ )
1277 regsZ80[i].isFree = 1;
1280 /*-----------------------------------------------------------------*/
1281 /* deallocStackSpil - this will set the stack pointer back */
1282 /*-----------------------------------------------------------------*/
1283 DEFSETFUNC(deallocStackSpil)
1291 /** Register reduction for assignment.
1293 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1297 D(D_ALLOC, ("packRegsForAssing: running on ic %zi\n", ic));
1300 /* !IS_TRUE_SYMOP(IC_RESULT(ic)) ||*/
1301 !IS_ITEMP(IC_RIGHT(ic)) ||
1302 OP_LIVETO(IC_RIGHT(ic)) > ic->seq ||
1303 OP_SYMBOL(IC_RIGHT(ic))->isind)
1307 /* if the true symbol is defined in far space or on stack
1308 then we should not since this will increase register pressure */
1309 if (isOperandInFarSpace(IC_RESULT(ic))) {
1310 if ((dic = farSpacePackable(ic)))
1317 /* find the definition of iTempNN scanning backwards if we find a
1318 a use of the true symbol in before we find the definition then
1320 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1321 /* if there is a function call and this is
1322 a parameter & not my parameter then don't pack it */
1323 if ( (dic->op == CALL || dic->op == PCALL) &&
1324 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1325 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1333 if (IS_SYMOP(IC_RESULT(dic)) &&
1334 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1338 if (IS_SYMOP(IC_RIGHT(dic)) &&
1339 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1340 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1345 if (IS_SYMOP(IC_LEFT(dic)) &&
1346 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1347 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1352 if (POINTER_SET(dic) &&
1353 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1361 return 0 ; /* did not find */
1363 /* if the result is on stack or iaccess then it must be
1364 the same atleast one of the operands */
1365 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1366 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1368 /* the operation has only one symbol
1369 operator then we can pack */
1370 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1371 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1374 if (!((IC_LEFT(dic) &&
1375 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1377 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1381 /* found the definition */
1382 /* replace the result with the result of */
1383 /* this assignment and remove this assignment */
1384 IC_RESULT(dic) = IC_RESULT(ic) ;
1386 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1387 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1389 /* delete from liverange table also
1390 delete from all the points inbetween and the new
1392 for ( sic = dic; sic != ic ; sic = sic->next ) {
1393 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1394 if (IS_ITEMP(IC_RESULT(dic)))
1395 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1398 remiCodeFromeBBlock(ebp,ic);
1403 /** Scanning backwards looks for first assig found.
1405 iCode *findAssignToSym (operand *op,iCode *ic)
1409 for (dic = ic->prev ; dic ; dic = dic->prev) {
1411 /* if definition by assignment */
1412 if (dic->op == '=' &&
1413 !POINTER_SET(dic) &&
1414 IC_RESULT(dic)->key == op->key)
1415 /* && IS_TRUE_SYMOP(IC_RIGHT(dic))*/
1418 /* we are interested only if defined in far space */
1419 /* or in stack space in case of + & - */
1421 /* if assigned to a non-symbol then return
1423 if (!IS_SYMOP(IC_RIGHT(dic)))
1426 /* if the symbol is in far space then
1428 if (isOperandInFarSpace(IC_RIGHT(dic)))
1431 /* for + & - operations make sure that
1432 if it is on the stack it is the same
1433 as one of the three operands */
1434 if ((ic->op == '+' || ic->op == '-') &&
1435 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1437 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1438 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1439 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1447 /* if we find an usage then we cannot delete it */
1448 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1451 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1454 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1458 /* now make sure that the right side of dic
1459 is not defined between ic & dic */
1461 iCode *sic = dic->next ;
1463 for (; sic != ic ; sic = sic->next)
1464 if (IC_RESULT(sic) &&
1465 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1474 /*-----------------------------------------------------------------*/
1475 /* packRegsForSupport :- reduce some registers for support calls */
1476 /*-----------------------------------------------------------------*/
1477 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1480 /* for the left & right operand :- look to see if the
1481 left was assigned a true symbol in far space in that
1482 case replace them */
1483 D(D_ALLOC, ("packRegsForSupport: running on ic %zi\n", ic));
1485 if (IS_ITEMP(IC_LEFT(ic)) &&
1486 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1487 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1493 /* found it we need to remove it from the
1495 for ( sic = dic; sic != ic ; sic = sic->next )
1496 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1498 IC_LEFT(ic)->operand.symOperand =
1499 IC_RIGHT(dic)->operand.symOperand;
1500 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1501 remiCodeFromeBBlock(ebp,dic);
1505 /* do the same for the right operand */
1508 IS_ITEMP(IC_RIGHT(ic)) &&
1509 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1510 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1516 /* found it we need to remove it from the block */
1517 for ( sic = dic; sic != ic ; sic = sic->next )
1518 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1520 IC_RIGHT(ic)->operand.symOperand =
1521 IC_RIGHT(dic)->operand.symOperand;
1522 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1524 remiCodeFromeBBlock(ebp,dic);
1531 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1533 /** Will reduce some registers for single use.
1535 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1540 D(D_ALLOC, ("packRegsForOneUse: running on ic %zi\n", ic));
1542 /* if returning a literal then do nothing */
1546 /* only upto 2 bytes since we cannot predict
1547 the usage of b, & acc */
1548 if (getSize(operandType(op)) > 2 &&
1553 /* this routine will mark the a symbol as used in one
1554 instruction use only && if the defintion is local
1555 (ie. within the basic block) && has only one definition &&
1556 that definiion is either a return value from a
1557 function or does not contain any variables in
1559 uses = bitVectCopy(OP_USES(op));
1560 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1561 if (!bitVectIsZero(uses)) /* has other uses */
1564 /* if it has only one defintion */
1565 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1566 return NULL ; /* has more than one definition */
1568 /* get the that definition */
1570 hTabItemWithKey(iCodehTab,
1571 bitVectFirstBit(OP_DEFS(op)))))
1574 /* found the definition now check if it is local */
1575 if (dic->seq < ebp->fSeq ||
1576 dic->seq > ebp->lSeq)
1577 return NULL ; /* non-local */
1579 /* now check if it is the return from a function call */
1580 if (dic->op == CALL || dic->op == PCALL ) {
1581 if (ic->op != SEND && ic->op != RETURN) {
1582 OP_SYMBOL(op)->ruonly = 1;
1588 /* otherwise check that the definition does
1589 not contain any symbols in far space */
1590 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1591 isOperandInFarSpace(IC_RIGHT(dic)) ||
1592 IS_OP_RUONLY(IC_LEFT(ic)) ||
1593 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1597 /* if pointer set then make sure the pointer is one byte */
1598 if (POINTER_SET(dic))
1601 if (POINTER_GET(dic))
1606 /* also make sure the intervenening instructions
1607 don't have any thing in far space */
1608 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1609 /* if there is an intervening function call then no */
1610 if (dic->op == CALL || dic->op == PCALL)
1612 /* if pointer set then make sure the pointer
1614 if (POINTER_SET(dic))
1617 if (POINTER_GET(dic))
1620 /* if address of & the result is remat the okay */
1621 if (dic->op == ADDRESS_OF &&
1622 OP_SYMBOL(IC_RESULT(dic))->remat)
1625 /* if left or right or result is in far space */
1626 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1627 isOperandInFarSpace(IC_RIGHT(dic)) ||
1628 isOperandInFarSpace(IC_RESULT(dic)) ||
1629 IS_OP_RUONLY(IC_LEFT(dic)) ||
1630 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1631 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1636 OP_SYMBOL(op)->ruonly = 1;
1640 /*-----------------------------------------------------------------*/
1641 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1642 /*-----------------------------------------------------------------*/
1643 static bool isBitwiseOptimizable (iCode *ic)
1645 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1647 /* bitwise operations are considered optimizable
1648 under the following conditions (Jean-Louis VERN)
1660 if (IS_LITERAL(rtype))
1666 Certian assignments involving pointers can be temporarly stored
1677 /** Pack registers for acc use.
1678 When the result of this operation is small and short lived it may
1679 be able to be stored in the accumelator.
1681 static void packRegsForAccUse (iCode *ic)
1685 /* if + or - then it has to be one byte result */
1686 if ((ic->op == '+' || ic->op == '-')
1687 && getSize(operandType(IC_RESULT(ic))) > 1)
1690 /* if shift operation make sure right side is not a literal */
1691 if (ic->op == RIGHT_OP &&
1692 (isOperandLiteral(IC_RIGHT(ic)) ||
1693 getSize(operandType(IC_RESULT(ic))) > 1))
1696 if (ic->op == LEFT_OP &&
1697 ( isOperandLiteral(IC_RIGHT(ic)) ||
1698 getSize(operandType(IC_RESULT(ic))) > 1))
1701 /* has only one definition */
1702 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1705 /* has only one use */
1706 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1709 /* and the usage immediately follows this iCode */
1710 if (!(uic = hTabItemWithKey(iCodehTab,
1711 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1714 if (ic->next != uic)
1717 /* if it is a conditional branch then we definitely can */
1718 if (uic->op == IFX )
1721 if ( uic->op == JUMPTABLE )
1725 /* if the usage is not is an assignment or an
1726 arithmetic / bitwise / shift operation then not */
1727 if (POINTER_SET(uic) &&
1728 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1732 if (uic->op != '=' &&
1733 !IS_ARITHMETIC_OP(uic) &&
1734 !IS_BITWISE_OP(uic) &&
1735 uic->op != LEFT_OP &&
1736 uic->op != RIGHT_OP )
1739 /* if used in ^ operation then make sure right is not a
1741 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1744 /* if shift operation make sure right side is not a literal */
1745 if (uic->op == RIGHT_OP &&
1746 ( isOperandLiteral(IC_RIGHT(uic)) ||
1747 getSize(operandType(IC_RESULT(uic))) > 1))
1750 if (uic->op == LEFT_OP &&
1751 ( isOperandLiteral(IC_RIGHT(uic)) ||
1752 getSize(operandType(IC_RESULT(uic))) > 1))
1756 /* make sure that the result of this icode is not on the
1757 stack, since acc is used to compute stack offset */
1758 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1759 OP_SYMBOL(IC_RESULT(uic))->onStack)
1764 /* if either one of them in far space then we cannot */
1765 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1766 isOperandInFarSpace(IC_LEFT(uic))) ||
1767 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1768 isOperandInFarSpace(IC_RIGHT(uic))))
1772 /* if the usage has only one operand then we can */
1773 if (IC_LEFT(uic) == NULL ||
1774 IC_RIGHT(uic) == NULL)
1777 /* make sure this is on the left side if not
1778 a '+' since '+' is commutative */
1779 if (ic->op != '+' &&
1780 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1783 /* if one of them is a literal then we can */
1784 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1785 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1786 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1790 /** This is confusing :) Guess for now */
1791 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1792 (IS_ITEMP(IC_RIGHT(uic)) ||
1793 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
1796 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1797 (IS_ITEMP(IC_LEFT(uic)) ||
1798 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
1802 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1805 bool opPreservesA(iCode *ic, iCode *uic)
1807 /* if it is a conditional branch then we definitely can */
1808 if (uic->op == IFX )
1811 if ( uic->op == JUMPTABLE )
1814 /* if the usage has only one operand then we can */
1815 /* PENDING: check */
1816 if (IC_LEFT(uic) == NULL ||
1817 IC_RIGHT(uic) == NULL)
1820 /* PENDING: check this rule */
1821 if (getSize(operandType(IC_RESULT(uic))) > 1) {
1827 !IS_ARITHMETIC_OP(uic) (sub requires A)
1831 !IS_BITWISE_OP(uic) &&
1834 !POINTER_GET(uic) &&
1836 uic->op != LEFT_OP &&
1837 uic->op != RIGHT_OP &&*/
1844 if (!IC_LEFT(uic) || !IC_RESULT(ic))
1847 /** This is confusing :) Guess for now */
1848 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1849 (IS_ITEMP(IC_RIGHT(uic)) ||
1850 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
1853 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1854 (IS_ITEMP(IC_LEFT(uic)) ||
1855 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
1861 /** Pack registers for acc use.
1862 When the result of this operation is small and short lived it may
1863 be able to be stored in the accumelator.
1865 Note that the 'A preserving' list is currently emperical :)e
1867 static void packRegsForAccUse2(iCode *ic)
1871 D(D_ALLOC, ("packRegsForAccUse2: running on ic %zi\n", ic));
1873 /* Filter out all but those 'good' commands */
1877 !IS_BITWISE_OP(ic) &&
1884 /* if + or - then it has to be one byte result.
1887 if ((ic->op == '+' || ic->op == '-')
1888 && getSize(operandType(IC_RESULT(ic))) > 1)
1891 /* if shift operation make sure right side is not a literal.
1895 if (ic->op == RIGHT_OP &&
1896 (isOperandLiteral(IC_RIGHT(ic)) ||
1897 getSize(operandType(IC_RESULT(ic))) > 1))
1900 if (ic->op == LEFT_OP &&
1901 ( isOperandLiteral(IC_RIGHT(ic)) ||
1902 getSize(operandType(IC_RESULT(ic))) > 1))
1906 /* has only one definition */
1907 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1) {
1911 /* Right. We may be able to propagate it through if:
1912 For each in the chain of uses the intermediate is OK.
1914 /* Get next with 'uses result' bit on
1915 If this->next == next
1916 Validate use of next
1917 If OK, increase count
1919 /* and the usage immediately follows this iCode */
1920 if (!(uic = hTabItemWithKey(iCodehTab,
1921 bitVectFirstBit(OP_USES(IC_RESULT(ic)))))) {
1926 /* Create a copy of the OP_USES bit vect */
1927 bitVect *uses = bitVectCopy(OP_USES(IC_RESULT(ic)));
1929 iCode *scan = ic, *next;
1932 setBit = bitVectFirstBit(uses);
1933 next = hTabItemWithKey(iCodehTab, setBit);
1934 if (scan->next == next) {
1935 bitVectUnSetBit(uses, setBit);
1936 /* Still contigous. */
1937 if (!opPreservesA(ic, next)) {
1945 } while (!bitVectIsZero(uses));
1946 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1950 /* OLD CODE FOLLOWS */
1951 /* if it is a conditional branch then we definitely can
1955 if (uic->op == IFX )
1959 if ( uic->op == JUMPTABLE )
1963 /* if the usage is not is an assignment or an
1964 arithmetic / bitwise / shift operation then not.
1965 MLH: Pending: Invalid. Our pointer sets are always peechy.
1968 if (POINTER_SET(uic) &&
1969 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1) {
1970 printf("e5 %u\n", getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)));
1976 if (uic->op != '=' &&
1977 !IS_ARITHMETIC_OP(uic) &&
1978 !IS_BITWISE_OP(uic) &&
1979 uic->op != LEFT_OP &&
1980 uic->op != RIGHT_OP ) {
1985 /* if used in ^ operation then make sure right is not a
1987 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1990 /* if shift operation make sure right side is not a literal */
1991 if (uic->op == RIGHT_OP &&
1992 ( isOperandLiteral(IC_RIGHT(uic)) ||
1993 getSize(operandType(IC_RESULT(uic))) > 1))
1996 if (uic->op == LEFT_OP &&
1997 ( isOperandLiteral(IC_RIGHT(uic)) ||
1998 getSize(operandType(IC_RESULT(uic))) > 1))
2002 /* make sure that the result of this icode is not on the
2003 stack, since acc is used to compute stack offset */
2004 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
2005 OP_SYMBOL(IC_RESULT(uic))->onStack)
2010 /* if either one of them in far space then we cannot */
2011 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
2012 isOperandInFarSpace(IC_LEFT(uic))) ||
2013 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
2014 isOperandInFarSpace(IC_RIGHT(uic))))
2018 /* if the usage has only one operand then we can */
2019 if (IC_LEFT(uic) == NULL ||
2020 IC_RIGHT(uic) == NULL)
2023 /* make sure this is on the left side if not
2024 a '+' since '+' is commutative */
2025 if (ic->op != '+' &&
2026 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
2029 /* if one of them is a literal then we can */
2030 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
2031 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
2032 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2036 /** This is confusing :) Guess for now */
2037 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
2038 (IS_ITEMP(IC_RIGHT(uic)) ||
2039 (IS_TRUE_SYMOP(IC_RIGHT(uic)))))
2042 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
2043 (IS_ITEMP(IC_LEFT(uic)) ||
2044 (IS_TRUE_SYMOP(IC_LEFT(uic)))))
2048 printf("acc ok!\n");
2049 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2052 /** Does some transformations to reduce register pressure.
2054 static void packRegisters (eBBlock *ebp)
2059 D(D_ALLOC, ("packRegisters: entered.\n"));
2061 while (1 && !DISABLE_PACK_ASSIGN) {
2063 /* look for assignments of the form */
2064 /* iTempNN = TRueSym (someoperation) SomeOperand */
2066 /* TrueSym := iTempNN:1 */
2067 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2068 /* find assignment of the form TrueSym := iTempNN:1 */
2069 if (ic->op == '=' && !POINTER_SET(ic))
2070 change += packRegsForAssign(ic,ebp);
2076 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2077 /* Safe: address of a true sym is always constant. */
2078 /* if this is an itemp & result of a address of a true sym
2079 then mark this as rematerialisable */
2081 D(D_ALLOC, ("packRegisters: looping on ic %zi\n", ic));
2083 if (ic->op == ADDRESS_OF &&
2084 IS_ITEMP(IC_RESULT(ic)) &&
2085 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2086 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2087 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2089 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2090 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2091 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2094 /* Safe: just propagates the remat flag */
2095 /* if straight assignment then carry remat flag if this is the
2097 if (ic->op == '=' &&
2099 IS_SYMOP(IC_RIGHT(ic)) &&
2100 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2101 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2103 OP_SYMBOL(IC_RESULT(ic))->remat =
2104 OP_SYMBOL(IC_RIGHT(ic))->remat;
2105 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2106 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2109 /* if the condition of an if instruction is defined in the
2110 previous instruction then mark the itemp as a conditional */
2111 if ((IS_CONDITIONAL(ic) ||
2112 ( ( ic->op == BITWISEAND ||
2115 isBitwiseOptimizable(ic))) &&
2116 ic->next && ic->next->op == IFX &&
2117 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2118 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2120 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2125 /* reduce for support function calls */
2126 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2127 packRegsForSupport(ic,ebp);
2131 /* some cases the redundant moves can
2132 can be eliminated for return statements */
2133 if ((ic->op == RETURN || ic->op == SEND) &&
2134 !isOperandInFarSpace(IC_LEFT(ic)) &&
2136 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2138 /* if pointer set & left has a size more than
2139 one and right is not in far space */
2140 if (POINTER_SET(ic) &&
2141 /* MLH: no such thing.
2142 !isOperandInFarSpace(IC_RIGHT(ic)) && */
2143 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2144 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2145 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2147 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2149 /* if pointer get */
2150 if (POINTER_GET(ic) &&
2151 /* MLH: dont have far space
2152 !isOperandInFarSpace(IC_RESULT(ic))&& */
2153 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2154 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2155 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2156 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2157 /* pack registers for accumulator use, when the result of an
2158 arithmetic or bit wise operation has only one use, that use is
2159 immediately following the defintion and the using iCode has
2160 only one operand or has two operands but one is literal & the
2161 result of that operation is not on stack then we can leave the
2162 result of this operation in acc:b combination */
2164 if ((IS_ARITHMETIC_OP(ic)
2165 || IS_BITWISE_OP(ic)
2166 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2168 IS_ITEMP(IC_RESULT(ic)) &&
2169 getSize(operandType(IC_RESULT(ic))) <= 2)
2170 packRegsForAccUse (ic);
2172 if (!DISABLE_PACK_ACC && IS_ITEMP(IC_RESULT(ic)) &&
2173 getSize(operandType(IC_RESULT(ic))) == 1)
2174 packRegsForAccUse2(ic);
2179 /*-----------------------------------------------------------------*/
2180 /* assignRegisters - assigns registers to each live range as need */
2181 /*-----------------------------------------------------------------*/
2182 void z80_assignRegisters (eBBlock **ebbs, int count)
2187 D(D_ALLOC, ("\n-> z80_assignRegisters: entered.\n"));
2189 setToNull((void *)&funcrUsed);
2190 stackExtend = dataExtend = 0;
2193 /* DE is required for the code gen. */
2194 _nRegs = GBZ80_MAX_REGS;
2195 regsZ80 = _gbz80_regs;
2198 _nRegs = Z80_MAX_REGS;
2199 regsZ80 = _z80_regs;
2202 /* change assignments this will remove some
2203 live ranges reducing some register pressure */
2204 for (i = 0 ; i < count ;i++ )
2205 packRegisters (ebbs[i]);
2207 if (options.dump_pack)
2208 dumpEbbsToFileExt(".dumppack",ebbs,count);
2210 /* first determine for each live range the number of
2211 registers & the type of registers required for each */
2214 /* and serially allocate registers */
2215 serialRegAssign(ebbs,count);
2217 /* if stack was extended then tell the user */
2219 /* werror(W_TOOMANY_SPILS,"stack", */
2220 /* stackExtend,currFunc->name,""); */
2225 /* werror(W_TOOMANY_SPILS,"data space", */
2226 /* dataExtend,currFunc->name,""); */
2230 if (options.dump_rassgn)
2231 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2233 /* after that create the register mask
2234 for each of the instruction */
2235 createRegMask (ebbs,count);
2237 /* now get back the chain */
2238 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2240 /* redo that offsets for stacked automatic variables */
2241 redoStackOffsets ();
2245 /* free up any stackSpil locations allocated */
2246 applyToSet(stackSpil,deallocStackSpil);
2248 setToNull((void **)&stackSpil);
2249 setToNull((void **)&spiltSet);
2250 /* mark all registers as free */