1 /** @name Z80 Register allocation functions.
4 Note: much of this is ripped straight from Sandeep's mcs51 code.
6 This code maps the virtual symbols and code onto the real
7 hardware. It allocates based on usage and how long the varible
8 lives into registers or temporary memory on the stack.
10 On the Z80 hl and ix and a are reserved for the code generator,
11 leaving bc and de for allocation. iy is unusable due to currently
12 as it's only adressable as a pair. The extra register pressure
13 from reserving hl is made up for by how much easier the sub
14 operations become. You could swap hl for iy if the undocumented
15 iyl/iyh instructions are available.
17 The stack frame is the common ix-bp style. Basically:
22 ix+0: calling functions ix
25 sp: end of local varibles
27 There is currently no support for bit spaces or banked functions.
29 This program is free software; you can redistribute it and/or
30 modify it under the terms of the GNU General Public License as
31 published by the Free Software Foundation; either version 2, or (at
32 your option) any later version. This program is distributed in the
33 hope that it will be useful, but WITHOUT ANY WARRANTY; without even
34 the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
35 PURPOSE. See the GNU General Public License for more details.
37 You should have received a copy of the GNU General Public License
38 along with this program; if not, write to the Free Software
39 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
40 USA. In other words, you are welcome to use, share and improve
41 this program. You are forbidden to forbid anyone else to use,
42 share and improve what you give them. Help stamp out
48 /* Flags to turn off optimisations.
53 DISABLE_PACK_ASSIGN = 0,
54 /* Pack for one use is quite broken. */
55 DISABLE_PACK_ONE_USE = 1,
59 /* Flags to turn on debugging code.
66 D_ACCUSE2_VERBOSE = 0,
71 #define D(_a, _s) if (_a) { printf _s; fflush(stdout); }
76 #define DISABLE_PACKREGSFORSUPPORT 1
77 #define DISABLE_PACKREGSFORACCUSE 1
79 extern void genZ80Code (iCode *);
81 /** Local static variables */
89 /* registers used in a function */
96 static regs _gbz80_regs[] =
98 {REG_GPR, C_IDX, "c", 1},
99 {REG_GPR, B_IDX, "b", 1},
100 {REG_CND, CND_IDX, "c", 1}
103 static regs _z80_regs[] =
105 {REG_GPR, C_IDX, "c", 1},
106 {REG_GPR, B_IDX, "b", 1},
107 {REG_GPR, E_IDX, "e", 1},
108 {REG_GPR, D_IDX, "d", 1},
109 {REG_CND, CND_IDX, "c", 1}
114 /** Number of usable registers (all but C) */
115 #define Z80_MAX_REGS ((sizeof(_z80_regs)/sizeof(_z80_regs[0]))-1)
116 #define GBZ80_MAX_REGS ((sizeof(_gbz80_regs)/sizeof(_gbz80_regs[0]))-1)
118 static void spillThis (symbol *);
120 /** Allocates register of given type.
121 'type' is not used on the z80 version. It was used to select
122 between pointer and general purpose registers on the mcs51 version.
124 @return Pointer to the newly allocated register.
127 allocReg (short type)
131 for (i = 0; i < _G.nRegs; i++)
133 /* For now we allocate from any free */
134 if (regsZ80[i].isFree)
136 regsZ80[i].isFree = 0;
139 currFunc->regsUsed = bitVectSetBit (currFunc->regsUsed, i);
141 D (D_ALLOC, ("allocReg: alloced %p\n", ®sZ80[i]));
145 D (D_ALLOC, ("allocReg: No free.\n"));
149 /** Returns pointer to register wit index number
156 for (i = 0; i < _G.nRegs; i++)
158 if (regsZ80[i].rIdx == idx)
164 wassertl (0, "regWithIdx not found");
168 /** Frees a register.
173 wassert (!reg->isFree);
175 D (D_ALLOC, ("freeReg: freed %p\n", reg));
179 /** Returns number of free registers.
187 for (i = 0; i < _G.nRegs; i++)
189 /* For now only one reg type */
190 if (regsZ80[i].isFree)
198 /** Free registers with type.
201 nfreeRegsType (int type)
206 if ((nfr = nFreeRegs (type)) == 0)
208 return nFreeRegs (REG_GPR);
212 return nFreeRegs (type);
217 /*-----------------------------------------------------------------*/
218 /* allDefsOutOfRange - all definitions are out of a range */
219 /*-----------------------------------------------------------------*/
221 allDefsOutOfRange (bitVect * defs, int fseq, int toseq)
228 for (i = 0; i < defs->size; i++)
232 if (bitVectBitValue (defs, i) &&
233 (ic = hTabItemWithKey (iCodehTab, i)) &&
234 (ic->seq >= fseq && ic->seq <= toseq))
244 /*-----------------------------------------------------------------*/
245 /* computeSpillable - given a point find the spillable live ranges */
246 /*-----------------------------------------------------------------*/
248 computeSpillable (iCode * ic)
252 /* spillable live ranges are those that are live at this
253 point . the following categories need to be subtracted
255 a) - those that are already spilt
256 b) - if being used by this one
257 c) - defined by this one */
259 spillable = bitVectCopy (ic->rlive);
261 bitVectCplAnd (spillable, _G.spiltSet); /* those already spilt */
263 bitVectCplAnd (spillable, ic->uses); /* used in this one */
264 bitVectUnSetBit (spillable, ic->defKey);
265 spillable = bitVectIntersect (spillable, _G.regAssigned);
270 /*-----------------------------------------------------------------*/
271 /* noSpilLoc - return true if a variable has no spil location */
272 /*-----------------------------------------------------------------*/
274 noSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
276 return (sym->usl.spillLoc ? 0 : 1);
279 /*-----------------------------------------------------------------*/
280 /* hasSpilLoc - will return 1 if the symbol has spil location */
281 /*-----------------------------------------------------------------*/
283 hasSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
285 return (sym->usl.spillLoc ? 1 : 0);
288 /** Will return 1 if the remat flag is set.
289 A symbol is rematerialisable if it doesnt need to be allocated
290 into registers at creation as it can be re-created at any time -
291 i.e. it's constant in some way.
294 rematable (symbol * sym, eBBlock * ebp, iCode * ic)
299 /*-----------------------------------------------------------------*/
300 /* allLRs - return true for all */
301 /*-----------------------------------------------------------------*/
303 allLRs (symbol * sym, eBBlock * ebp, iCode * ic)
308 /** liveRangesWith - applies function to a given set of live range
311 liveRangesWith (bitVect * lrs, int (func) (symbol *, eBBlock *, iCode *),
312 eBBlock * ebp, iCode * ic)
317 if (!lrs || !lrs->size)
320 for (i = 1; i < lrs->size; i++)
323 if (!bitVectBitValue (lrs, i))
326 /* if we don't find it in the live range
327 hash table we are in serious trouble */
328 if (!(sym = hTabItemWithKey (liveRanges, i)))
330 wassertl (0, "liveRangesWith could not find liveRange");
334 if (func (sym, ebp, ic) && bitVectBitValue (_G.regAssigned, sym->key))
336 addSetHead (&rset, sym);
344 /** leastUsedLR - given a set determines which is the least used
347 leastUsedLR (set * sset)
349 symbol *sym = NULL, *lsym = NULL;
351 sym = lsym = setFirstItem (sset);
356 for (; lsym; lsym = setNextItem (sset))
359 /* if usage is the same then prefer
360 the spill the smaller of the two */
361 if (lsym->used == sym->used)
362 if (getSize (lsym->type) < getSize (sym->type))
366 if (lsym->used < sym->used)
371 setToNull ((void **) &sset);
376 /** noOverLap - will iterate through the list looking for over lap
379 noOverLap (set * itmpStack, symbol * fsym)
383 for (sym = setFirstItem (itmpStack); sym;
384 sym = setNextItem (itmpStack))
386 // if sym starts before (or on) our end point
387 // and ends after (or on) our start point,
389 if (sym->liveFrom <= fsym->liveTo &&
390 sym->liveTo >= fsym->liveFrom)
398 /*-----------------------------------------------------------------*/
399 /* isFree - will return 1 if the a free spil location is found */
400 /*-----------------------------------------------------------------*/
404 V_ARG (symbol **, sloc);
405 V_ARG (symbol *, fsym);
407 /* if already found */
411 /* if it is free && and the itmp assigned to
412 this does not have any overlapping live ranges
413 with the one currently being assigned and
414 the size can be accomodated */
416 noOverLap (sym->usl.itmpStack, fsym) &&
417 getSize (sym->type) >= getSize (fsym->type))
426 /*-----------------------------------------------------------------*/
427 /* createStackSpil - create a location on the stack to spil */
428 /*-----------------------------------------------------------------*/
430 createStackSpil (symbol * sym)
434 D (D_ALLOC, ("createStackSpil: for sym %p\n", sym));
436 /* first go try and find a free one that is already
437 existing on the stack */
438 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
440 /* found a free one : just update & return */
441 sym->usl.spillLoc = sloc;
444 addSetHead (&sloc->usl.itmpStack, sym);
445 D (D_ALLOC, ("createStackSpil: found existing\n"));
449 /* could not then have to create one , this is the hard part
450 we need to allocate this on the stack : this is really a
451 hack!! but cannot think of anything better at this time */
453 sprintf (buffer, "sloc%d", _G.slocNum++);
454 sloc = newiTemp (buffer);
456 /* set the type to the spilling symbol */
457 sloc->type = copyLinkChain (sym->type);
458 sloc->etype = getSpec (sloc->type);
459 SPEC_SCLS (sloc->etype) = S_AUTO;
463 sloc->isref = 1; /* to prevent compiler warning */
465 /* if it is on the stack then update the stack */
466 if (IN_STACK (sloc->etype))
468 currFunc->stack += getSize (sloc->type);
469 _G.stackExtend += getSize (sloc->type);
473 _G.dataExtend += getSize (sloc->type);
476 /* add it to the stackSpil set */
477 addSetHead (&_G.stackSpil, sloc);
478 sym->usl.spillLoc = sloc;
481 /* add it to the set of itempStack set
482 of the spill location */
483 addSetHead (&sloc->usl.itmpStack, sym);
485 D (D_ALLOC, ("createStackSpil: created new\n"));
489 /*-----------------------------------------------------------------*/
490 /* spillThis - spils a specific operand */
491 /*-----------------------------------------------------------------*/
493 spillThis (symbol * sym)
497 D (D_ALLOC, ("spillThis: spilling %p\n", sym));
499 /* if this is rematerializable or has a spillLocation
500 we are okay, else we need to create a spillLocation
502 if (!(sym->remat || sym->usl.spillLoc))
504 createStackSpil (sym);
507 /* mark it has spilt & put it in the spilt set */
509 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
511 bitVectUnSetBit (_G.regAssigned, sym->key);
513 for (i = 0; i < sym->nRegs; i++)
517 freeReg (sym->regs[i]);
522 if (sym->usl.spillLoc && !sym->remat)
524 sym->usl.spillLoc->allocreq = 1;
530 /*-----------------------------------------------------------------*/
531 /* allDefsOutOfRange - all definitions are out of a range */
532 /*-----------------------------------------------------------------*/
534 allDefsOutOfRange (bitVect * defs, int fseq, int toseq)
541 for (i = 0; i < defs->size; i++)
545 if (bitVectBitValue (defs, i) &&
546 (ic = hTabItemWithKey (iCodehTab, i)) &&
547 (ic->seq >= fseq && ic->seq <= toseq))
556 /*-----------------------------------------------------------------*/
557 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location */
558 /* but is not used as a pointer */
559 /*-----------------------------------------------------------------*/
561 hasSpilLocnoUptr (symbol * sym, eBBlock * ebp, iCode * ic)
563 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
566 /*-----------------------------------------------------------------*/
567 /* notUsedInBlock - not used in this block */
568 /*-----------------------------------------------------------------*/
570 notUsedInBlock (symbol * sym, eBBlock * ebp, iCode * ic)
572 return (!bitVectBitsInCommon (sym->defs, ebp->usesDefs) &&
573 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
574 /* return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs)); */
577 /*-----------------------------------------------------------------*/
578 /* notUsedInRemaining - not used or defined in remain of the block */
579 /*-----------------------------------------------------------------*/
581 notUsedInRemaining (symbol * sym, eBBlock * ebp, iCode * ic)
583 return ((usedInRemaining (operandFromSymbol (sym), ic) ? 0 : 1) &&
584 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
588 /** Select a iTemp to spil : rather a simple procedure.
591 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
593 bitVect *lrcs = NULL;
597 D (D_ALLOC, ("selectSpil: finding spill for ic %p\n", ic));
598 /* get the spillable live ranges */
599 lrcs = computeSpillable (ic);
601 /* get all live ranges that are rematerizable */
602 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
604 D (D_ALLOC, ("selectSpil: using remat.\n"));
605 /* return the least used of these */
606 return leastUsedLR (selectS);
610 /* get live ranges with spillLocations in direct space */
611 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
613 sym = leastUsedLR (selectS);
614 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
615 sym->usl.spillLoc->rname :
616 sym->usl.spillLoc->name));
618 /* mark it as allocation required */
619 sym->usl.spillLoc->allocreq = 1;
623 /* if the symbol is local to the block then */
624 if (forSym->liveTo < ebp->lSeq)
627 /* check if there are any live ranges allocated
628 to registers that are not used in this block */
629 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
631 sym = leastUsedLR (selectS);
632 /* if this is not rematerializable */
636 wassertl (0, "Attempted to do an unsupported block spill");
642 /* check if there are any live ranges that not
643 used in the remainder of the block */
644 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
646 sym = leastUsedLR (selectS);
651 wassertl (0, "Attempted to do an unsupported remain spill");
659 /* find live ranges with spillocation && not used as pointers */
660 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
663 sym = leastUsedLR (selectS);
664 /* mark this as allocation required */
665 sym->usl.spillLoc->allocreq = 1;
670 /* find live ranges with spillocation */
671 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
673 D (D_ALLOC, ("selectSpil: using with spill.\n"));
674 sym = leastUsedLR (selectS);
675 sym->usl.spillLoc->allocreq = 1;
679 /* couldn't find then we need to create a spil
680 location on the stack , for which one? the least
682 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
684 D (D_ALLOC, ("selectSpil: creating new spill.\n"));
685 /* return a created spil location */
686 sym = createStackSpil (leastUsedLR (selectS));
687 sym->usl.spillLoc->allocreq = 1;
691 /* this is an extreme situation we will spill
692 this one : happens very rarely but it does happen */
693 D (D_ALLOC, ("selectSpil: using spillThis.\n"));
699 /** Spil some variable & mark registers as free.
700 A spill occurs when an iTemp wont fit into the available registers.
703 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
708 D (D_ALLOC, ("spilSomething: spilling on ic %p\n", ic));
710 /* get something we can spil */
711 ssym = selectSpil (ic, ebp, forSym);
713 /* mark it as spilt */
715 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
717 /* mark it as not register assigned &
718 take it away from the set */
719 bitVectUnSetBit (_G.regAssigned, ssym->key);
721 /* mark the registers as free */
722 for (i = 0; i < ssym->nRegs; i++)
724 freeReg (ssym->regs[i]);
726 wassertl (ssym->blockSpil == 0, "Encountered a sym with a block spill");
727 wassertl (ssym->remainSpil == 0, "Encountered a sym with a remain spill");
729 /* if spilt on stack then free up r0 & r1
730 if they could have been assigned to as gprs */
731 if (!ptrRegReq && isSpiltOnStack (ssym))
734 spillLRWithPtrReg (ssym);
737 /* if this was a block level spil then insert push & pop
738 at the start & end of block respectively */
741 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
742 /* add push to the start of the block */
743 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
744 ebp->sch->next : ebp->sch));
745 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
746 /* add pop to the end of the block */
747 addiCodeToeBBlock (ebp, nic, NULL);
750 /* if spilt because not used in the remainder of the
751 block then add a push before this instruction and
752 a pop at the end of the block */
753 if (ssym->remainSpil)
756 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
757 /* add push just before this instruction */
758 addiCodeToeBBlock (ebp, nic, ic);
760 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
761 /* add pop to the end of the block */
762 addiCodeToeBBlock (ebp, nic, NULL);
766 D (D_ALLOC, ("spilSomething: done.\n"));
774 /** Will try for GPR if not spil.
777 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
781 D (D_ALLOC, ("getRegGpr: on ic %p\n", ic));
783 /* try for gpr type */
784 if ((reg = allocReg (REG_GPR)))
786 D (D_ALLOC, ("getRegGpr: got a reg.\n"));
790 /* we have to spil */
791 if (!spilSomething (ic, ebp, sym))
793 D (D_ALLOC, ("getRegGpr: have to spill.\n"));
797 /* this looks like an infinite loop but
798 in really selectSpil will abort */
802 /** Symbol has a given register.
805 symHasReg (symbol * sym, regs * reg)
809 for (i = 0; i < sym->nRegs; i++)
810 if (sym->regs[i] == reg)
816 /** Check the live to and if they have registers & are not spilt then
817 free up the registers
820 deassignLRs (iCode * ic, eBBlock * ebp)
826 for (sym = hTabFirstItem (liveRanges, &k); sym;
827 sym = hTabNextItem (liveRanges, &k))
831 /* if it does not end here */
832 if (sym->liveTo > ic->seq)
835 /* if it was spilt on stack then we can
836 mark the stack spil location as free */
841 sym->usl.spillLoc->isFree = 1;
847 if (!bitVectBitValue (_G.regAssigned, sym->key))
850 /* special case check if this is an IFX &
851 the privious one was a pop and the
852 previous one was not spilt then keep track
854 if (ic->op == IFX && ic->prev &&
855 ic->prev->op == IPOP &&
856 !ic->prev->parmPush &&
857 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
858 psym = OP_SYMBOL (IC_LEFT (ic->prev));
860 D (D_ALLOC, ("deassignLRs: in loop on sym %p nregs %u\n", sym, sym->nRegs));
866 bitVectUnSetBit (_G.regAssigned, sym->key);
868 /* if the result of this one needs registers
869 and does not have it then assign it right
871 if (IC_RESULT (ic) &&
872 !(SKIP_IC2 (ic) || /* not a special icode */
873 ic->op == JUMPTABLE ||
878 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
879 result->liveTo > ic->seq && /* and will live beyond this */
880 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
881 result->regType == sym->regType && /* same register types */
882 result->nRegs && /* which needs registers */
883 !result->isspilt && /* and does not already have them */
885 !bitVectBitValue (_G.regAssigned, result->key) &&
886 /* the number of free regs + number of regs in this LR
887 can accomodate the what result Needs */
888 ((nfreeRegsType (result->regType) +
889 sym->nRegs) >= result->nRegs)
892 for (i = 0; i < result->nRegs; i++)
895 result->regs[i] = sym->regs[i];
897 result->regs[i] = getRegGpr (ic, ebp, result);
899 /* if the allocation falied which means
900 this was spilt then break */
901 if (!result->regs[i])
909 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
912 /* free the remaining */
913 for (; i < sym->nRegs; i++)
917 if (!symHasReg (psym, sym->regs[i]))
918 freeReg (sym->regs[i]);
921 freeReg (sym->regs[i]);
922 // sym->regs[i] = NULL;
929 /** Reassign this to registers.
932 reassignLR (operand * op)
934 symbol *sym = OP_SYMBOL (op);
937 D (D_ALLOC, ("reassingLR: on sym %p\n", sym));
939 /* not spilt any more */
940 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
941 bitVectUnSetBit (_G.spiltSet, sym->key);
943 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
947 for (i = 0; i < sym->nRegs; i++)
948 sym->regs[i]->isFree = 0;
951 /** Determines if allocating will cause a spill.
954 willCauseSpill (int nr, int rt)
956 /* first check if there are any avlb registers
957 of te type required */
958 if (nFreeRegs (0) >= nr)
961 /* it will cause a spil */
965 /** The allocator can allocate same registers to result and operand,
966 if this happens make sure they are in the same position as the operand
967 otherwise chaos results.
970 positionRegs (symbol * result, symbol * opsym, int lineno)
972 int count = min (result->nRegs, opsym->nRegs);
973 int i, j = 0, shared = 0;
975 D (D_ALLOC, ("positionRegs: on result %p opsum %p line %u\n", result, opsym, lineno));
977 /* if the result has been spilt then cannot share */
982 /* first make sure that they actually share */
983 for (i = 0; i < count; i++)
985 for (j = 0; j < count; j++)
987 if (result->regs[i] == opsym->regs[j] && i != j)
997 regs *tmp = result->regs[i];
998 result->regs[i] = result->regs[j];
999 result->regs[j] = tmp;
1004 /** Try to allocate a pair of registers to the symbol.
1007 tryAllocatingRegPair (symbol * sym)
1010 wassert (sym->nRegs == 2);
1011 for (i = 0; i < _G.nRegs; i += 2)
1013 if ((regsZ80[i].isFree) && (regsZ80[i + 1].isFree))
1015 regsZ80[i].isFree = 0;
1016 sym->regs[0] = ®sZ80[i];
1017 regsZ80[i + 1].isFree = 0;
1018 sym->regs[1] = ®sZ80[i + 1];
1021 currFunc->regsUsed =
1022 bitVectSetBit (currFunc->regsUsed, i);
1023 currFunc->regsUsed =
1024 bitVectSetBit (currFunc->regsUsed, i + 1);
1026 D (D_ALLOC, ("tryAllocRegPair: succeded for sym %p\n", sym));
1030 D (D_ALLOC, ("tryAllocRegPair: failed on sym %p\n", sym));
1034 /** Serially allocate registers to the variables.
1035 This is the main register allocation function. It is called after
1039 serialRegAssign (eBBlock ** ebbs, int count)
1043 /* for all blocks */
1044 for (i = 0; i < count; i++)
1049 if (ebbs[i]->noPath &&
1050 (ebbs[i]->entryLabel != entryLabel &&
1051 ebbs[i]->entryLabel != returnLabel))
1054 /* of all instructions do */
1055 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1058 /* if this is an ipop that means some live
1059 range will have to be assigned again */
1063 reassignLR (IC_LEFT (ic));
1066 /* if result is present && is a true symbol */
1067 if (IC_RESULT (ic) && ic->op != IFX &&
1068 IS_TRUE_SYMOP (IC_RESULT (ic)))
1069 OP_SYMBOL (IC_RESULT (ic))->allocreq = 1;
1071 /* take away registers from live
1072 ranges that end at this instruction */
1073 deassignLRs (ic, ebbs[i]);
1075 /* some don't need registers */
1076 /* MLH: removed RESULT and POINTER_SET condition */
1077 if (SKIP_IC2 (ic) ||
1078 ic->op == JUMPTABLE ||
1084 /* now we need to allocate registers only for the result */
1087 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1092 D (D_ALLOC, ("serialRegAssign: in loop on result %p\n", sym));
1094 /* if it does not need or is spilt
1095 or is already assigned to registers
1096 or will not live beyond this instructions */
1099 bitVectBitValue (_G.regAssigned, sym->key) ||
1100 sym->liveTo <= ic->seq)
1102 D (D_ALLOC, ("serialRegAssign: wont live long enough.\n"));
1106 /* if some liverange has been spilt at the block level
1107 and this one live beyond this block then spil this
1109 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq)
1111 D (D_ALLOC, ("serialRegAssign: \"spilling to be safe.\"\n"));
1115 /* if trying to allocate this will cause
1116 a spill and there is nothing to spill
1117 or this one is rematerializable then
1119 willCS = willCauseSpill (sym->nRegs, sym->regType);
1120 spillable = computeSpillable (ic);
1122 (willCS && bitVectIsZero (spillable)))
1125 D (D_ALLOC, ("serialRegAssign: \"remat spill\"\n"));
1131 /* if it has a spillocation & is used less than
1132 all other live ranges then spill this */
1134 if (sym->usl.spillLoc) {
1135 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1136 allLRs, ebbs[i], ic));
1137 if (leastUsed && leastUsed->used > sym->used) {
1142 /* if none of the liveRanges have a spillLocation then better
1143 to spill this one than anything else already assigned to registers */
1144 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1151 /* else we assign registers to it */
1152 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1154 /* Special case: Try to fit into a reg pair if
1156 D (D_ALLOC, ("serialRegAssign: actually allocing regs!\n"));
1157 if ((sym->nRegs == 2) && tryAllocatingRegPair (sym))
1162 for (j = 0; j < sym->nRegs; j++)
1164 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1166 /* if the allocation falied which means
1167 this was spilt then break */
1170 D (D_ALLOC, ("Couldnt alloc (spill)\n"))
1175 /* if it shares registers with operands make sure
1176 that they are in the same position */
1177 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1178 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=')
1179 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1180 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1181 /* do the same for the right operand */
1182 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1183 OP_SYMBOL (IC_RIGHT (ic))->nRegs)
1184 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1185 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1192 /*-----------------------------------------------------------------*/
1193 /* rUmaskForOp :- returns register mask for an operand */
1194 /*-----------------------------------------------------------------*/
1196 rUmaskForOp (operand * op)
1202 /* only temporaries are assigned registers */
1206 sym = OP_SYMBOL (op);
1208 /* if spilt or no registers assigned to it
1210 if (sym->isspilt || !sym->nRegs)
1213 rumask = newBitVect (_G.nRegs);
1215 for (j = 0; j < sym->nRegs; j++)
1217 rumask = bitVectSetBit (rumask, sym->regs[j]->rIdx);
1224 z80_rUmaskForOp (operand * op)
1226 return rUmaskForOp (op);
1229 /** Returns bit vector of registers used in iCode.
1232 regsUsedIniCode (iCode * ic)
1234 bitVect *rmask = newBitVect (_G.nRegs);
1236 /* do the special cases first */
1239 rmask = bitVectUnion (rmask,
1240 rUmaskForOp (IC_COND (ic)));
1244 /* for the jumptable */
1245 if (ic->op == JUMPTABLE)
1247 rmask = bitVectUnion (rmask,
1248 rUmaskForOp (IC_JTCOND (ic)));
1253 /* of all other cases */
1255 rmask = bitVectUnion (rmask,
1256 rUmaskForOp (IC_LEFT (ic)));
1260 rmask = bitVectUnion (rmask,
1261 rUmaskForOp (IC_RIGHT (ic)));
1264 rmask = bitVectUnion (rmask,
1265 rUmaskForOp (IC_RESULT (ic)));
1271 /** For each instruction will determine the regsUsed.
1274 createRegMask (eBBlock ** ebbs, int count)
1278 /* for all blocks */
1279 for (i = 0; i < count; i++)
1283 if (ebbs[i]->noPath &&
1284 (ebbs[i]->entryLabel != entryLabel &&
1285 ebbs[i]->entryLabel != returnLabel))
1288 /* for all instructions */
1289 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1294 if (SKIP_IC2 (ic) || !ic->rlive)
1297 /* first mark the registers used in this
1299 ic->rUsed = regsUsedIniCode (ic);
1300 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1302 /* now create the register mask for those
1303 registers that are in use : this is a
1304 super set of ic->rUsed */
1305 ic->rMask = newBitVect (_G.nRegs + 1);
1307 /* for all live Ranges alive at this point */
1308 for (j = 1; j < ic->rlive->size; j++)
1313 /* if not alive then continue */
1314 if (!bitVectBitValue (ic->rlive, j))
1317 /* find the live range we are interested in */
1318 if (!(sym = hTabItemWithKey (liveRanges, j)))
1320 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1321 "createRegMask cannot find live range");
1325 /* if no register assigned to it */
1326 if (!sym->nRegs || sym->isspilt)
1329 /* for all the registers allocated to it */
1330 for (k = 0; k < sym->nRegs; k++)
1333 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1339 /** Returns the rematerialized string for a remat var.
1342 rematStr (symbol * sym)
1345 iCode *ic = sym->rematiCode;
1350 /* if plus or minus print the right hand side */
1351 if (ic->op == '+' || ic->op == '-')
1353 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1356 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1359 /* we reached the end */
1360 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1367 /*-----------------------------------------------------------------*/
1368 /* regTypeNum - computes the type & number of registers required */
1369 /*-----------------------------------------------------------------*/
1376 /* for each live range do */
1377 for (sym = hTabFirstItem (liveRanges, &k); sym;
1378 sym = hTabNextItem (liveRanges, &k))
1381 /* if used zero times then no registers needed */
1382 if ((sym->liveTo - sym->liveFrom) == 0)
1385 D (D_ALLOC, ("regTypeNum: loop on sym %p\n", sym));
1387 /* if the live range is a temporary */
1391 /* if the type is marked as a conditional */
1392 if (sym->regType == REG_CND)
1395 /* if used in return only then we don't
1397 if (sym->ruonly || sym->accuse)
1399 if (IS_AGGREGATE (sym->type) || sym->isptr)
1400 sym->type = aggrToPtr (sym->type, FALSE);
1404 /* if not then we require registers */
1405 D (D_ALLOC, ("regTypeNum: isagg %u nRegs %u type %p\n", IS_AGGREGATE (sym->type) || sym->isptr, sym->nRegs, sym->type));
1406 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1407 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1408 getSize (sym->type));
1409 D (D_ALLOC, ("regTypeNum: setting nRegs of %s (%p) to %u\n", sym->name, sym, sym->nRegs));
1411 D (D_ALLOC, ("regTypeNum: setup to assign regs sym %p\n", sym));
1415 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1416 printTypeChain (sym->type, stderr);
1417 fprintf (stderr, "\n");
1420 /* determine the type of register required */
1421 /* Always general purpose */
1422 sym->regType = REG_GPR;
1427 /* for the first run we don't provide */
1428 /* registers for true symbols we will */
1429 /* see how things go */
1430 D (D_ALLOC, ("regTypeNum: #2 setting num of %p to 0\n", sym));
1437 /** Mark all registers as free.
1444 D (D_ALLOC, ("freeAllRegs: running.\n"));
1446 for (i = 0; i < _G.nRegs; i++)
1447 regsZ80[i].isFree = 1;
1450 /*-----------------------------------------------------------------*/
1451 /* deallocStackSpil - this will set the stack pointer back */
1452 /*-----------------------------------------------------------------*/
1453 DEFSETFUNC (deallocStackSpil)
1461 /** Register reduction for assignment.
1464 packRegsForAssign (iCode * ic, eBBlock * ebp)
1468 D (D_ALLOC, ("packRegsForAssign: running on ic %p\n", ic));
1470 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1471 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1472 OP_LIVETO (IC_RIGHT (ic)) > ic->seq)
1478 /* if the true symbol is defined in far space or on stack
1479 then we should not since this will increase register pressure */
1480 if (isOperandInFarSpace (IC_RESULT (ic)))
1482 if ((dic = farSpacePackable (ic)))
1489 /* find the definition of iTempNN scanning backwards if we find a
1490 a use of the true symbol in before we find the definition then
1492 for (dic = ic->prev; dic; dic = dic->prev)
1494 /* if there is a function call and this is
1495 a parameter & not my parameter then don't pack it */
1496 if ((dic->op == CALL || dic->op == PCALL) &&
1497 (OP_SYMBOL (IC_RESULT (ic))->_isparm &&
1498 !OP_SYMBOL (IC_RESULT (ic))->ismyparm))
1507 if (IS_SYMOP (IC_RESULT (dic)) &&
1508 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1513 if (IS_SYMOP (IC_RIGHT (dic)) &&
1514 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1515 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1521 if (IS_SYMOP (IC_LEFT (dic)) &&
1522 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1523 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1529 if (POINTER_SET (dic) &&
1530 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1539 return 0; /* did not find */
1541 /* if the result is on stack or iaccess then it must be
1542 the same atleast one of the operands */
1543 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1544 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1547 /* the operation has only one symbol
1548 operator then we can pack */
1549 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1550 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1553 if (!((IC_LEFT (dic) &&
1554 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1556 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1560 /* found the definition */
1561 /* replace the result with the result of */
1562 /* this assignment and remove this assignment */
1563 IC_RESULT (dic) = IC_RESULT (ic);
1565 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1567 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1569 /* delete from liverange table also
1570 delete from all the points inbetween and the new
1572 for (sic = dic; sic != ic; sic = sic->next)
1574 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1575 if (IS_ITEMP (IC_RESULT (dic)))
1576 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1579 remiCodeFromeBBlock (ebp, ic);
1580 // PENDING: Check vs mcs51
1584 /** Scanning backwards looks for first assig found.
1587 findAssignToSym (operand * op, iCode * ic)
1591 for (dic = ic->prev; dic; dic = dic->prev)
1594 /* if definition by assignment */
1595 if (dic->op == '=' &&
1596 !POINTER_SET (dic) &&
1597 IC_RESULT (dic)->key == op->key)
1598 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1601 /* we are interested only if defined in far space */
1602 /* or in stack space in case of + & - */
1604 /* if assigned to a non-symbol then return
1606 if (!IS_SYMOP (IC_RIGHT (dic)))
1609 /* if the symbol is in far space then
1611 if (isOperandInFarSpace (IC_RIGHT (dic)))
1614 /* for + & - operations make sure that
1615 if it is on the stack it is the same
1616 as one of the three operands */
1617 if ((ic->op == '+' || ic->op == '-') &&
1618 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1621 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1622 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1623 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1631 /* if we find an usage then we cannot delete it */
1632 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1635 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1638 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1642 /* now make sure that the right side of dic
1643 is not defined between ic & dic */
1646 iCode *sic = dic->next;
1648 for (; sic != ic; sic = sic->next)
1649 if (IC_RESULT (sic) &&
1650 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1659 #if !DISABLE_PACKREGSFORSUPPORT
1662 /*-----------------------------------------------------------------*/
1663 /* packRegsForSupport :- reduce some registers for support calls */
1664 /*-----------------------------------------------------------------*/
1666 packRegsForSupport (iCode * ic, eBBlock * ebp)
1669 /* for the left & right operand :- look to see if the
1670 left was assigned a true symbol in far space in that
1671 case replace them */
1672 D (D_ALLOC, ("packRegsForSupport: running on ic %p\n", ic));
1674 if (IS_ITEMP (IC_LEFT (ic)) &&
1675 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1677 iCode *dic = findAssignToSym (IC_LEFT (ic), ic);
1683 /* found it we need to remove it from the
1685 for (sic = dic; sic != ic; sic = sic->next)
1686 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1688 IC_LEFT (ic)->operand.symOperand =
1689 IC_RIGHT (dic)->operand.symOperand;
1690 IC_LEFT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1691 remiCodeFromeBBlock (ebp, dic);
1692 // PENDING: Check vs mcs51
1696 /* do the same for the right operand */
1699 IS_ITEMP (IC_RIGHT (ic)) &&
1700 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1702 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1708 /* found it we need to remove it from the block */
1709 for (sic = dic; sic != ic; sic = sic->next)
1710 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1712 IC_RIGHT (ic)->operand.symOperand =
1713 IC_RIGHT (dic)->operand.symOperand;
1714 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1716 remiCodeFromeBBlock (ebp, dic);
1717 // PENDING: vs mcs51
1725 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1727 /** Will reduce some registers for single use.
1730 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1736 D (D_ALLOC, ("packRegsForOneUse: running on ic %p\n", ic));
1738 /* if returning a literal then do nothing */
1742 /* only upto 2 bytes since we cannot predict
1743 the usage of b, & acc */
1744 if (getSize (operandType (op)) > 2 &&
1749 /* this routine will mark the a symbol as used in one
1750 instruction use only && if the defintion is local
1751 (ie. within the basic block) && has only one definition &&
1752 that definiion is either a return value from a
1753 function or does not contain any variables in
1755 uses = bitVectCopy (OP_USES (op));
1756 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1757 if (!bitVectIsZero (uses)) /* has other uses */
1760 /* if it has only one defintion */
1761 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1762 return NULL; /* has more than one definition */
1764 /* get the that definition */
1766 hTabItemWithKey (iCodehTab,
1767 bitVectFirstBit (OP_DEFS (op)))))
1770 /* found the definition now check if it is local */
1771 if (dic->seq < ebp->fSeq ||
1772 dic->seq > ebp->lSeq)
1773 return NULL; /* non-local */
1775 /* now check if it is the return from a function call */
1776 if (dic->op == CALL || dic->op == PCALL)
1778 if (ic->op != SEND && ic->op != RETURN)
1780 OP_SYMBOL (op)->ruonly = 1;
1786 /* otherwise check that the definition does
1787 not contain any symbols in far space */
1788 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1789 isOperandInFarSpace (IC_RIGHT (dic)) ||
1790 IS_OP_RUONLY (IC_LEFT (ic)) ||
1791 IS_OP_RUONLY (IC_RIGHT (ic)))
1796 /* if pointer set then make sure the pointer is one byte */
1797 if (POINTER_SET (dic))
1800 if (POINTER_GET (dic))
1805 /* also make sure the intervenening instructions
1806 don't have any thing in far space */
1807 for (dic = dic->next; dic && dic != ic; dic = dic->next)
1809 /* if there is an intervening function call then no */
1810 if (dic->op == CALL || dic->op == PCALL)
1812 /* if pointer set then make sure the pointer
1814 if (POINTER_SET (dic))
1817 if (POINTER_GET (dic))
1820 /* if address of & the result is remat the okay */
1821 if (dic->op == ADDRESS_OF &&
1822 OP_SYMBOL (IC_RESULT (dic))->remat)
1825 /* if left or right or result is in far space */
1826 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1827 isOperandInFarSpace (IC_RIGHT (dic)) ||
1828 isOperandInFarSpace (IC_RESULT (dic)) ||
1829 IS_OP_RUONLY (IC_LEFT (dic)) ||
1830 IS_OP_RUONLY (IC_RIGHT (dic)) ||
1831 IS_OP_RUONLY (IC_RESULT (dic)))
1837 OP_SYMBOL (op)->ruonly = 1;
1841 /*-----------------------------------------------------------------*/
1842 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1843 /*-----------------------------------------------------------------*/
1845 isBitwiseOptimizable (iCode * ic)
1847 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
1849 /* bitwise operations are considered optimizable
1850 under the following conditions (Jean-Louis VERN)
1862 if (IS_LITERAL (rtype))
1868 Certian assignments involving pointers can be temporarly stored
1879 #if !DISABLE_PACKREGSFORACCUSE
1882 /** Pack registers for acc use.
1883 When the result of this operation is small and short lived it may
1884 be able to be stored in the accumelator.
1887 packRegsForAccUse (iCode * ic)
1891 /* if + or - then it has to be one byte result */
1892 if ((ic->op == '+' || ic->op == '-')
1893 && getSize (operandType (IC_RESULT (ic))) > 1)
1896 /* if shift operation make sure right side is not a literal */
1897 if (ic->op == RIGHT_OP &&
1898 (isOperandLiteral (IC_RIGHT (ic)) ||
1899 getSize (operandType (IC_RESULT (ic))) > 1))
1902 if (ic->op == LEFT_OP &&
1903 (isOperandLiteral (IC_RIGHT (ic)) ||
1904 getSize (operandType (IC_RESULT (ic))) > 1))
1907 /* has only one definition */
1908 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
1911 /* has only one use */
1912 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
1915 /* and the usage immediately follows this iCode */
1916 if (!(uic = hTabItemWithKey (iCodehTab,
1917 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
1920 if (ic->next != uic)
1923 /* if it is a conditional branch then we definitely can */
1927 if (uic->op == JUMPTABLE)
1931 /* if the usage is not is an assignment or an
1932 arithmetic / bitwise / shift operation then not */
1933 if (POINTER_SET (uic) &&
1934 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
1938 if (uic->op != '=' &&
1939 !IS_ARITHMETIC_OP (uic) &&
1940 !IS_BITWISE_OP (uic) &&
1941 uic->op != LEFT_OP &&
1942 uic->op != RIGHT_OP)
1945 /* if used in ^ operation then make sure right is not a
1947 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
1950 /* if shift operation make sure right side is not a literal */
1951 if (uic->op == RIGHT_OP &&
1952 (isOperandLiteral (IC_RIGHT (uic)) ||
1953 getSize (operandType (IC_RESULT (uic))) > 1))
1956 if (uic->op == LEFT_OP &&
1957 (isOperandLiteral (IC_RIGHT (uic)) ||
1958 getSize (operandType (IC_RESULT (uic))) > 1))
1962 /* make sure that the result of this icode is not on the
1963 stack, since acc is used to compute stack offset */
1964 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
1965 OP_SYMBOL (IC_RESULT (uic))->onStack)
1970 /* if either one of them in far space then we cannot */
1971 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
1972 isOperandInFarSpace (IC_LEFT (uic))) ||
1973 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
1974 isOperandInFarSpace (IC_RIGHT (uic))))
1978 /* if the usage has only one operand then we can */
1979 if (IC_LEFT (uic) == NULL ||
1980 IC_RIGHT (uic) == NULL)
1983 /* make sure this is on the left side if not
1984 a '+' since '+' is commutative */
1985 if (ic->op != '+' &&
1986 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
1989 // See mcs51 ralloc for reasoning
1991 /* if one of them is a literal then we can */
1992 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
1993 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2000 /** This is confusing :) Guess for now */
2001 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2002 (IS_ITEMP (IC_RIGHT (uic)) ||
2003 (IS_TRUE_SYMOP (IC_RIGHT (uic)))))
2006 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2007 (IS_ITEMP (IC_LEFT (uic)) ||
2008 (IS_TRUE_SYMOP (IC_LEFT (uic)))))
2012 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2017 packRegsForHLUse (iCode * ic)
2021 /* has only one definition */
2022 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2024 D (D_HLUSE, (" + Dropping as has more than one def\n"));
2028 /* has only one use */
2029 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2031 D (D_HLUSE, (" + Dropping as has more than one use\n"));
2035 /* and the usage immediately follows this iCode */
2036 if (!(uic = hTabItemWithKey (iCodehTab,
2037 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2039 D (D_HLUSE, (" + Dropping as usage isn't in this block\n"));
2043 if (ic->next != uic)
2045 D (D_HLUSE, (" + Dropping as usage doesn't follow this\n"));
2049 if (getSize (operandType (IC_RESULT (ic))) != 2)
2051 D (D_HLUSE, (" + Dropping as the result size is not 2\n"));
2056 if (ic->op == CAST && uic->op == IPUSH)
2058 if (ic->op == ADDRESS_OF && uic->op == IPUSH)
2060 if (ic->op == CALL && ic->parmBytes == 0 && (uic->op == '-' || uic->op == '+'))
2065 /* Case of assign a constant to offset in a static array. */
2066 if (ic->op == '+' && IS_VALOP (IC_RIGHT (ic)))
2068 if (uic->op == '=' && POINTER_SET (uic))
2072 else if (uic->op == IPUSH && getSize (operandType (IC_LEFT (uic))) == 2)
2079 D (D_HLUSE, (" + Dropping as it's a bad op\n"));
2082 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_SCRATCH;
2086 opPreservesA (iCode * ic, iCode * uic)
2090 /* If we've gotten this far then the thing to compare must be
2091 small enough and must be in A.
2096 if (uic->op == JUMPTABLE)
2098 D (D_ACCUSE2, (" + Dropping as operation is a Jumptable\n"));
2102 /* A pointer assign preserves A if A is the left value. */
2103 if (uic->op == '=' && POINTER_SET (uic))
2108 /* if the usage has only one operand then we can */
2109 /* PENDING: check */
2110 if (IC_LEFT (uic) == NULL ||
2111 IC_RIGHT (uic) == NULL)
2113 D (D_ACCUSE2, (" + Dropping as operation has only one operand\n"));
2117 /* PENDING: check this rule */
2118 if (getSize (operandType (IC_RESULT (uic))) > 1)
2120 D (D_ACCUSE2, (" + Dropping as operation has size is too big\n"));
2125 /* Disabled all of the old rules as they weren't verified and have
2126 caused at least one problem.
2132 opIgnoresA (iCode * ic, iCode * uic)
2134 /* A increment of an iTemp by a constant is OK. */
2135 if ( uic->op == '+' &&
2136 IS_ITEMP (IC_LEFT (uic)) &&
2137 IS_ITEMP (IC_RESULT (uic)) &&
2138 IS_OP_LITERAL (IC_RIGHT (uic)))
2140 unsigned int icount = (unsigned int) floatFromVal (IC_RIGHT (uic)->operand.valOperand);
2142 /* Being an ITEMP means that we're already a symbol. */
2144 IC_RESULT (uic)->operand.symOperand->key == IC_LEFT (uic)->operand.symOperand->key
2155 /* Some optimisation cases:
2167 ; genAssign (pointer)
2171 want to optimise down to:
2177 So genPointer get is OK
2178 genPlus where the right is constant, left is iTemp, and result is same as left
2179 genAssign (pointer) is OK
2190 ; genAssign (pointer)
2191 ; AOP_STK for _strcpy_to_1_1
2196 want to optimise down to:
2202 So genIfx where IC_COND has size of 1 and is a constant.
2205 /** Pack registers for acc use.
2206 When the result of this operation is small and short lived it may
2207 be able to be stored in the accumulator.
2209 Note that the 'A preserving' list is currently emperical :)
2212 packRegsForAccUse2 (iCode * ic)
2216 D (D_ALLOC, ("packRegsForAccUse2: running on ic %p\n", ic));
2218 /* Filter out all but those 'good' commands */
2220 !POINTER_GET (ic) &&
2222 !IS_BITWISE_OP (ic) &&
2228 D (D_ACCUSE2, (" + Dropping as not a 'good' source command\n"));
2232 /* if + or - then it has to be one byte result.
2235 if ((ic->op == '+' || ic->op == '-')
2236 && getSize (operandType (IC_RESULT (ic))) > 1)
2238 D (D_ACCUSE2, (" + Dropping as it's a big + or -\n"));
2242 /* has only one definition */
2243 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2245 D (D_ACCUSE2, (" + Dropping as it has more than one definition\n"));
2249 /* Right. We may be able to propagate it through if:
2250 For each in the chain of uses the intermediate is OK.
2252 /* Get next with 'uses result' bit on
2253 If this->next == next
2254 Validate use of next
2255 If OK, increase count
2257 /* and the usage immediately follows this iCode */
2258 if (!(uic = hTabItemWithKey (iCodehTab,
2259 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2261 D (D_ACCUSE2, (" + Dropping as usage does not follow first\n"));
2266 /* Create a copy of the OP_USES bit vect */
2267 bitVect *uses = bitVectCopy (OP_USES (IC_RESULT (ic)));
2269 iCode *scan = ic, *next;
2273 setBit = bitVectFirstBit (uses);
2274 next = hTabItemWithKey (iCodehTab, setBit);
2275 if (scan->next == next)
2277 D (D_ACCUSE2_VERBOSE, (" ! Is next in line\n"));
2279 bitVectUnSetBit (uses, setBit);
2280 /* Still contigous. */
2281 if (!opPreservesA (ic, next))
2283 D (D_ACCUSE2, (" + Dropping as operation doesn't preserve A\n"));
2286 D (D_ACCUSE2_VERBOSE, (" ! Preserves A, so continue scanning\n"));
2289 else if (scan->next == NULL && bitVectnBitsOn (uses) == 1 && next != NULL)
2291 if (next->prev == NULL)
2293 if (!opPreservesA (ic, next))
2295 D (D_ACCUSE2, (" + Dropping as operation doesn't preserve A #2\n"));
2298 bitVectUnSetBit (uses, setBit);
2303 D (D_ACCUSE2, (" + Dropping as last in list and next doesn't start a block\n"));
2307 else if (scan->next == NULL)
2309 D (D_ACCUSE2, (" + Dropping as hit the end of the list\n"));
2310 D (D_ACCUSE2, (" + Next in htab: %p\n", next));
2315 if (opIgnoresA (ic, scan->next))
2319 D (D_ACCUSE2_VERBOSE, (" ! Op ignores A, so continue scanning\n"));
2323 D (D_ACCUSE2, (" + Dropping as parts are not consecuitive and intermediate might use A\n"));
2328 while (!bitVectIsZero (uses));
2330 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2334 /* OLD CODE FOLLOWS */
2335 /* if it is a conditional branch then we definitely can
2343 if (uic->op == JUMPTABLE)
2347 /* if the usage is not is an assignment or an
2348 arithmetic / bitwise / shift operation then not.
2349 MLH: Pending: Invalid. Our pointer sets are always peechy.
2352 if (POINTER_SET (uic) &&
2353 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2355 printf ("e5 %u\n", getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)));
2361 if (uic->op != '=' &&
2362 !IS_ARITHMETIC_OP (uic) &&
2363 !IS_BITWISE_OP (uic) &&
2364 uic->op != LEFT_OP &&
2365 uic->op != RIGHT_OP)
2371 /* if used in ^ operation then make sure right is not a
2373 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2376 /* if shift operation make sure right side is not a literal */
2377 if (uic->op == RIGHT_OP &&
2378 (isOperandLiteral (IC_RIGHT (uic)) ||
2379 getSize (operandType (IC_RESULT (uic))) > 1))
2382 if (uic->op == LEFT_OP &&
2383 (isOperandLiteral (IC_RIGHT (uic)) ||
2384 getSize (operandType (IC_RESULT (uic))) > 1))
2388 /* make sure that the result of this icode is not on the
2389 stack, since acc is used to compute stack offset */
2390 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2391 OP_SYMBOL (IC_RESULT (uic))->onStack)
2396 /* if either one of them in far space then we cannot */
2397 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2398 isOperandInFarSpace (IC_LEFT (uic))) ||
2399 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2400 isOperandInFarSpace (IC_RIGHT (uic))))
2404 /* if the usage has only one operand then we can */
2405 if (IC_LEFT (uic) == NULL ||
2406 IC_RIGHT (uic) == NULL)
2409 /* make sure this is on the left side if not
2410 a '+' since '+' is commutative */
2411 if (ic->op != '+' &&
2412 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2415 /* if one of them is a literal then we can */
2416 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2417 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2423 /** This is confusing :) Guess for now */
2424 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2425 (IS_ITEMP (IC_RIGHT (uic)) ||
2426 (IS_TRUE_SYMOP (IC_RIGHT (uic)))))
2429 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2430 (IS_ITEMP (IC_LEFT (uic)) ||
2431 (IS_TRUE_SYMOP (IC_LEFT (uic)))))
2435 printf ("acc ok!\n");
2436 OP_SYMBOL (IC_RESULT (ic))->accuse = ACCUSE_A;
2439 /** Does some transformations to reduce register pressure.
2442 packRegisters (eBBlock * ebp)
2447 D (D_ALLOC, ("packRegisters: entered.\n"));
2449 while (1 && !DISABLE_PACK_ASSIGN)
2452 /* look for assignments of the form */
2453 /* iTempNN = TRueSym (someoperation) SomeOperand */
2455 /* TrueSym := iTempNN:1 */
2456 for (ic = ebp->sch; ic; ic = ic->next)
2458 /* find assignment of the form TrueSym := iTempNN:1 */
2459 if (ic->op == '=' && !POINTER_SET (ic))
2460 change += packRegsForAssign (ic, ebp);
2466 for (ic = ebp->sch; ic; ic = ic->next)
2468 /* Safe: address of a true sym is always constant. */
2469 /* if this is an itemp & result of a address of a true sym
2470 then mark this as rematerialisable */
2471 D (D_ALLOC, ("packRegisters: looping on ic %p\n", ic));
2473 if (ic->op == ADDRESS_OF &&
2474 IS_ITEMP (IC_RESULT (ic)) &&
2475 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2476 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2477 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2480 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2481 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2482 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2485 /* Safe: just propagates the remat flag */
2486 /* if straight assignment then carry remat flag if this is the
2488 if (ic->op == '=' &&
2489 !POINTER_SET (ic) &&
2490 IS_SYMOP (IC_RIGHT (ic)) &&
2491 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2492 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2495 OP_SYMBOL (IC_RESULT (ic))->remat =
2496 OP_SYMBOL (IC_RIGHT (ic))->remat;
2497 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2498 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2501 /* if the condition of an if instruction is defined in the
2502 previous instruction then mark the itemp as a conditional */
2503 if ((IS_CONDITIONAL (ic) ||
2504 ((ic->op == BITWISEAND ||
2507 isBitwiseOptimizable (ic))) &&
2508 ic->next && ic->next->op == IFX &&
2509 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2510 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2511 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2514 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2519 /* reduce for support function calls */
2520 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2521 packRegsForSupport (ic, ebp);
2524 /* if pointer set & left has a size more than
2525 one and right is not in far space */
2526 if (!DISABLE_PACK_ONE_USE &&
2528 /* MLH: no such thing.
2529 !isOperandInFarSpace(IC_RIGHT(ic)) && */
2530 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2531 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2532 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2535 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2538 /* if pointer get */
2539 if (!DISABLE_PACK_ONE_USE &&
2541 /* MLH: dont have far space
2542 !isOperandInFarSpace(IC_RESULT(ic))&& */
2543 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2544 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2545 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2548 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2551 /* pack registers for accumulator use, when the result of an
2552 arithmetic or bit wise operation has only one use, that use is
2553 immediately following the defintion and the using iCode has
2554 only one operand or has two operands but one is literal & the
2555 result of that operation is not on stack then we can leave the
2556 result of this operation in acc:b combination */
2558 if (!DISABLE_PACK_HL && IS_ITEMP (IC_RESULT (ic)))
2560 packRegsForHLUse (ic);
2563 if (!DISABLE_PACK_ACC && IS_ITEMP (IC_RESULT (ic)) &&
2564 getSize (operandType (IC_RESULT (ic))) == 1)
2566 packRegsForAccUse2 (ic);
2571 /** Joins together two byte constant pushes into one word push.
2574 joinPushes (iCode *lic)
2578 for (ic = lic; ic; ic = ic->next)
2585 /* Anything past this? */
2590 /* This and the next pushes? */
2591 if (ic->op != IPUSH || uic->op != IPUSH)
2595 /* Both literals? */
2596 if ( !IS_OP_LITERAL (IC_LEFT (ic)) || !IS_OP_LITERAL (IC_LEFT (uic)))
2600 /* Both characters? */
2601 if ( getSize (operandType (IC_LEFT (ic))) != 1 || getSize (operandType (IC_LEFT (uic))) != 1)
2605 /* Pull out the values, make a new type, and create the new iCode for it.
2607 first = (int)operandLitValue ( IC_LEFT (ic));
2608 second = (int)operandLitValue ( IC_LEFT (uic));
2610 sprintf (buffer, "%u", ((first << 8) | (second & 0xFF)) & 0xFFFFU);
2611 val = constVal (buffer);
2612 SPEC_NOUN (val->type) = V_INT;
2613 IC_LEFT (ic)->operand.valOperand = val;
2615 /* Now remove the second one from the list. */
2616 ic->next = uic->next;
2619 /* Patch up the reverse link */
2620 uic->next->prev = ic;
2627 /*-----------------------------------------------------------------*/
2628 /* assignRegisters - assigns registers to each live range as need */
2629 /*-----------------------------------------------------------------*/
2631 z80_assignRegisters (eBBlock ** ebbs, int count)
2636 D (D_ALLOC, ("\n-> z80_assignRegisters: entered.\n"));
2638 setToNull ((void *) &_G.funcrUsed);
2639 _G.stackExtend = _G.dataExtend = 0;
2643 /* DE is required for the code gen. */
2644 _G.nRegs = GBZ80_MAX_REGS;
2645 regsZ80 = _gbz80_regs;
2649 _G.nRegs = Z80_MAX_REGS;
2650 regsZ80 = _z80_regs;
2653 /* change assignments this will remove some
2654 live ranges reducing some register pressure */
2655 for (i = 0; i < count; i++)
2656 packRegisters (ebbs[i]);
2658 if (options.dump_pack)
2659 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2661 /* first determine for each live range the number of
2662 registers & the type of registers required for each */
2665 /* and serially allocate registers */
2666 serialRegAssign (ebbs, count);
2668 /* if stack was extended then tell the user */
2671 /* werror(W_TOOMANY_SPILS,"stack", */
2672 /* _G.stackExtend,currFunc->name,""); */
2678 /* werror(W_TOOMANY_SPILS,"data space", */
2679 /* _G.dataExtend,currFunc->name,""); */
2683 if (options.dump_rassgn) {
2684 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2685 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2688 /* after that create the register mask
2689 for each of the instruction */
2690 createRegMask (ebbs, count);
2692 /* now get back the chain */
2693 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2695 ic = joinPushes (ic);
2697 /* redo that offsets for stacked automatic variables */
2698 redoStackOffsets ();
2702 /* free up any stackSpil locations allocated */
2703 applyToSet (_G.stackSpil, deallocStackSpil);
2705 setToNull ((void **) &_G.stackSpil);
2706 setToNull ((void **) &_G.spiltSet);
2707 /* mark all registers as free */