1 /*------------------------------------------------------------------------
3 SDCCralloc.c - source file for register allocation. (8051) specific
5 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1998)
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding!
24 -------------------------------------------------------------------------*/
30 /*-----------------------------------------------------------------*/
31 /* At this point we start getting processor specific although */
32 /* some routines are non-processor specific & can be reused when */
33 /* targetting other processors. The decision for this will have */
34 /* to be made on a routine by routine basis */
35 /* routines used to pack registers are most definitely not reusable */
36 /* since the pack the registers depending strictly on the MCU */
37 /*-----------------------------------------------------------------*/
39 extern void gen51Code (iCode *);
48 bitVect *totRegAssigned; /* final set of LRs that got into registers */
51 bitVect *funcrUsed; /* registers used in a function */
57 /* Shared with gen.c */
58 int mcs51_ptrRegReq; /* one byte pointer register required */
64 {REG_GPR, R2_IDX, REG_GPR, "r2", "ar2", "0", 2, 1},
65 {REG_GPR, R3_IDX, REG_GPR, "r3", "ar3", "0", 3, 1},
66 {REG_GPR, R4_IDX, REG_GPR, "r4", "ar4", "0", 4, 1},
67 {REG_GPR, R5_IDX, REG_GPR, "r5", "ar5", "0", 5, 1},
68 {REG_GPR, R6_IDX, REG_GPR, "r6", "ar6", "0", 6, 1},
69 {REG_GPR, R7_IDX, REG_GPR, "r7", "ar7", "0", 7, 1},
70 {REG_PTR, R0_IDX, REG_PTR, "r0", "ar0", "0", 0, 1},
71 {REG_PTR, R1_IDX, REG_PTR, "r1", "ar1", "0", 1, 1},
72 {REG_GPR, X8_IDX, REG_GPR, "x8", "x8", "xreg", 0, 1},
73 {REG_GPR, X9_IDX, REG_GPR, "x9", "x9", "xreg", 1, 1},
74 {REG_GPR, X10_IDX, REG_GPR, "x10", "x10", "xreg", 2, 1},
75 {REG_GPR, X11_IDX, REG_GPR, "x11", "x11", "xreg", 3, 1},
76 {REG_GPR, X12_IDX, REG_GPR, "x12", "x12", "xreg", 4, 1},
77 {REG_CND, CND_IDX, REG_CND, "C", "C", "xreg", 0, 1},
80 static void spillThis (symbol *);
81 static void freeAllRegs ();
83 /*-----------------------------------------------------------------*/
84 /* allocReg - allocates register of given type */
85 /*-----------------------------------------------------------------*/
91 for (i = 0; i < mcs51_nRegs; i++)
94 /* if type is given as 0 then any
95 free register will do */
99 regs8051[i].isFree = 0;
102 bitVectSetBit (currFunc->regsUsed, i);
105 /* other wise look for specific type
107 if (regs8051[i].isFree &&
108 regs8051[i].type == type)
110 regs8051[i].isFree = 0;
113 bitVectSetBit (currFunc->regsUsed, i);
120 /*-----------------------------------------------------------------*/
121 /* mcs51_regWithIdx - returns pointer to register wit index number */
122 /*-----------------------------------------------------------------*/
124 mcs51_regWithIdx (int idx)
128 for (i = 0; i < mcs51_nRegs; i++)
129 if (regs8051[i].rIdx == idx)
132 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
133 "regWithIdx not found");
137 /*-----------------------------------------------------------------*/
138 /* freeReg - frees a register */
139 /*-----------------------------------------------------------------*/
145 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
146 "freeReg - Freeing NULL register");
154 /*-----------------------------------------------------------------*/
155 /* nFreeRegs - returns number of free registers */
156 /*-----------------------------------------------------------------*/
163 for (i = 0; i < mcs51_nRegs; i++)
164 if (regs8051[i].isFree && regs8051[i].type == type)
169 /*-----------------------------------------------------------------*/
170 /* nfreeRegsType - free registers with type */
171 /*-----------------------------------------------------------------*/
173 nfreeRegsType (int type)
178 if ((nfr = nFreeRegs (type)) == 0)
179 return nFreeRegs (REG_GPR);
182 return nFreeRegs (type);
185 /*-----------------------------------------------------------------*/
186 /* useReg - marks a register as used */
187 /*-----------------------------------------------------------------*/
194 /*-----------------------------------------------------------------*/
195 /* computeSpillable - given a point find the spillable live ranges */
196 /*-----------------------------------------------------------------*/
198 computeSpillable (iCode * ic)
202 /* spillable live ranges are those that are live at this
203 point . the following categories need to be subtracted
205 a) - those that are already spilt
206 b) - if being used by this one
207 c) - defined by this one */
209 spillable = bitVectCopy (ic->rlive);
211 bitVectCplAnd (spillable, _G.spiltSet); /* those already spilt */
213 bitVectCplAnd (spillable, ic->uses); /* used in this one */
214 bitVectUnSetBit (spillable, ic->defKey);
215 spillable = bitVectIntersect (spillable, _G.regAssigned);
220 /*-----------------------------------------------------------------*/
221 /* noSpilLoc - return true if a variable has no spil location */
222 /*-----------------------------------------------------------------*/
224 noSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
226 return (sym->usl.spillLoc ? 0 : 1);
229 /*-----------------------------------------------------------------*/
230 /* hasSpilLoc - will return 1 if the symbol has spil location */
231 /*-----------------------------------------------------------------*/
233 hasSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
235 return (sym->usl.spillLoc ? 1 : 0);
238 /*-----------------------------------------------------------------*/
239 /* directSpilLoc - will return 1 if the splilocation is in direct */
240 /*-----------------------------------------------------------------*/
242 directSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
244 if (sym->usl.spillLoc &&
245 (IN_DIRSPACE (SPEC_OCLS (sym->usl.spillLoc->etype))))
251 /*-----------------------------------------------------------------*/
252 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location */
253 /* but is not used as a pointer */
254 /*-----------------------------------------------------------------*/
256 hasSpilLocnoUptr (symbol * sym, eBBlock * ebp, iCode * ic)
258 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
261 /*-----------------------------------------------------------------*/
262 /* rematable - will return 1 if the remat flag is set */
263 /*-----------------------------------------------------------------*/
265 rematable (symbol * sym, eBBlock * ebp, iCode * ic)
270 /*-----------------------------------------------------------------*/
271 /* notUsedInRemaining - not used or defined in remain of the block */
272 /*-----------------------------------------------------------------*/
274 notUsedInRemaining (symbol * sym, eBBlock * ebp, iCode * ic)
276 return ((usedInRemaining (operandFromSymbol (sym), ic) ? 0 : 1) &&
277 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
280 /*-----------------------------------------------------------------*/
281 /* allLRs - return true for all */
282 /*-----------------------------------------------------------------*/
284 allLRs (symbol * sym, eBBlock * ebp, iCode * ic)
289 /*-----------------------------------------------------------------*/
290 /* liveRangesWith - applies function to a given set of live range */
291 /*-----------------------------------------------------------------*/
293 liveRangesWith (bitVect * lrs, int (func) (symbol *, eBBlock *, iCode *),
294 eBBlock * ebp, iCode * ic)
299 if (!lrs || !lrs->size)
302 for (i = 1; i < lrs->size; i++)
305 if (!bitVectBitValue (lrs, i))
308 /* if we don't find it in the live range
309 hash table we are in serious trouble */
310 if (!(sym = hTabItemWithKey (liveRanges, i)))
312 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
313 "liveRangesWith could not find liveRange");
317 if (func (sym, ebp, ic) && bitVectBitValue (_G.regAssigned, sym->key))
318 addSetHead (&rset, sym);
325 /*-----------------------------------------------------------------*/
326 /* leastUsedLR - given a set determines which is the least used */
327 /*-----------------------------------------------------------------*/
329 leastUsedLR (set * sset)
331 symbol *sym = NULL, *lsym = NULL;
333 sym = lsym = setFirstItem (sset);
338 for (; lsym; lsym = setNextItem (sset))
341 /* if usage is the same then prefer
342 the spill the smaller of the two */
343 if (lsym->used == sym->used)
344 if (getSize (lsym->type) < getSize (sym->type))
348 if (lsym->used < sym->used)
353 setToNull ((void **) &sset);
358 /*-----------------------------------------------------------------*/
359 /* noOverLap - will iterate through the list looking for over lap */
360 /*-----------------------------------------------------------------*/
362 noOverLap (set * itmpStack, symbol * fsym)
367 for (sym = setFirstItem (itmpStack); sym;
368 sym = setNextItem (itmpStack))
370 if (bitVectBitValue(sym->clashes,fsym->key)) return 0;
376 /*-----------------------------------------------------------------*/
377 /* isFree - will return 1 if the a free spil location is found */
378 /*-----------------------------------------------------------------*/
383 V_ARG (symbol **, sloc);
384 V_ARG (symbol *, fsym);
386 /* if already found */
390 /* if it is free && and the itmp assigned to
391 this does not have any overlapping live ranges
392 with the one currently being assigned and
393 the size can be accomodated */
395 noOverLap (sym->usl.itmpStack, fsym) &&
396 getSize (sym->type) >= getSize (fsym->type))
405 /*-----------------------------------------------------------------*/
406 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
407 /*-----------------------------------------------------------------*/
409 spillLRWithPtrReg (symbol * forSym)
415 if (!_G.regAssigned ||
416 bitVectIsZero (_G.regAssigned))
419 r0 = mcs51_regWithIdx (R0_IDX);
420 r1 = mcs51_regWithIdx (R1_IDX);
422 /* for all live ranges */
423 for (lrsym = hTabFirstItem (liveRanges, &k); lrsym;
424 lrsym = hTabNextItem (liveRanges, &k))
428 /* if no registers assigned to it or spilt */
429 /* if it does not overlap with this then
430 not need to spill it */
432 if (lrsym->isspilt || !lrsym->nRegs ||
433 (lrsym->liveTo < forSym->liveFrom))
436 /* go thru the registers : if it is either
437 r0 or r1 then spil it */
438 for (j = 0; j < lrsym->nRegs; j++)
439 if (lrsym->regs[j] == r0 ||
440 lrsym->regs[j] == r1)
449 /*-----------------------------------------------------------------*/
450 /* createStackSpil - create a location on the stack to spil */
451 /*-----------------------------------------------------------------*/
453 createStackSpil (symbol * sym)
456 int useXstack, model;
460 /* first go try and find a free one that is already
461 existing on the stack */
462 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
464 /* found a free one : just update & return */
465 sym->usl.spillLoc = sloc;
468 addSetHead (&sloc->usl.itmpStack, sym);
472 /* could not then have to create one , this is the hard part
473 we need to allocate this on the stack : this is really a
474 hack!! but cannot think of anything better at this time */
476 if (sprintf (slocBuffer, "sloc%d", _G.slocNum++) >= sizeof (slocBuffer))
478 fprintf (stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
483 sloc = newiTemp (slocBuffer);
485 /* set the type to the spilling symbol */
486 sloc->type = copyLinkChain (sym->type);
487 sloc->etype = getSpec (sloc->type);
488 SPEC_SCLS (sloc->etype) = S_DATA;
489 SPEC_EXTR (sloc->etype) = 0;
490 SPEC_STAT (sloc->etype) = 0;
491 SPEC_VOLATILE(sloc->etype) = 0;
492 SPEC_ABSA(sloc->etype) = 0;
494 /* we don't allow it to be allocated`
495 onto the external stack since : so we
496 temporarily turn it off ; we also
497 turn off memory model to prevent
498 the spil from going to the external storage
501 useXstack = options.useXstack;
502 model = options.model;
503 /* noOverlay = options.noOverlay; */
504 /* options.noOverlay = 1; */
505 options.model = options.useXstack = 0;
509 options.useXstack = useXstack;
510 options.model = model;
511 /* options.noOverlay = noOverlay; */
512 sloc->isref = 1; /* to prevent compiler warning */
514 /* if it is on the stack then update the stack */
515 if (IN_STACK (sloc->etype))
517 currFunc->stack += getSize (sloc->type);
518 _G.stackExtend += getSize (sloc->type);
521 _G.dataExtend += getSize (sloc->type);
523 /* add it to the _G.stackSpil set */
524 addSetHead (&_G.stackSpil, sloc);
525 sym->usl.spillLoc = sloc;
528 /* add it to the set of itempStack set
529 of the spill location */
530 addSetHead (&sloc->usl.itmpStack, sym);
534 /*-----------------------------------------------------------------*/
535 /* isSpiltOnStack - returns true if the spil location is on stack */
536 /*-----------------------------------------------------------------*/
538 isSpiltOnStack (symbol * sym)
548 /* if (sym->_G.stackSpil) */
551 if (!sym->usl.spillLoc)
554 etype = getSpec (sym->usl.spillLoc->type);
555 if (IN_STACK (etype))
561 /*-----------------------------------------------------------------*/
562 /* spillThis - spils a specific operand */
563 /*-----------------------------------------------------------------*/
565 spillThis (symbol * sym)
568 /* if this is rematerializable or has a spillLocation
569 we are okay, else we need to create a spillLocation
571 if (!(sym->remat || sym->usl.spillLoc))
572 createStackSpil (sym);
574 /* mark it has spilt & put it in the spilt set */
575 sym->isspilt = sym->spillA = 1;
576 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
578 bitVectUnSetBit (_G.regAssigned, sym->key);
579 bitVectUnSetBit (_G.totRegAssigned, sym->key);
581 for (i = 0; i < sym->nRegs; i++)
585 freeReg (sym->regs[i]);
589 /* if spilt on stack then free up r0 & r1
590 if they could have been assigned to some
592 if (!mcs51_ptrRegReq && isSpiltOnStack (sym))
595 spillLRWithPtrReg (sym);
598 if (sym->usl.spillLoc && !sym->remat)
599 sym->usl.spillLoc->allocreq++;
603 /*-----------------------------------------------------------------*/
604 /* selectSpil - select a iTemp to spil : rather a simple procedure */
605 /*-----------------------------------------------------------------*/
607 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
609 bitVect *lrcs = NULL;
613 /* get the spillable live ranges */
614 lrcs = computeSpillable (ic);
616 /* get all live ranges that are rematerizable */
617 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
620 /* return the least used of these */
621 return leastUsedLR (selectS);
624 /* get live ranges with spillLocations in direct space */
625 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
627 sym = leastUsedLR (selectS);
628 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
629 sym->usl.spillLoc->rname :
630 sym->usl.spillLoc->name));
632 /* mark it as allocation required */
633 sym->usl.spillLoc->allocreq++;
637 /* if the symbol is local to the block then */
638 if (forSym->liveTo < ebp->lSeq)
641 /* check if there are any live ranges allocated
642 to registers that are not used in this block */
643 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
645 sym = leastUsedLR (selectS);
646 /* if this is not rematerializable */
655 /* check if there are any live ranges that not
656 used in the remainder of the block */
657 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
659 sym = leastUsedLR (selectS);
672 /* find live ranges with spillocation && not used as pointers */
673 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
676 sym = leastUsedLR (selectS);
677 /* mark this as allocation required */
678 sym->usl.spillLoc->allocreq++;
682 /* find live ranges with spillocation */
683 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
686 sym = leastUsedLR (selectS);
687 sym->usl.spillLoc->allocreq++;
691 /* couldn't find then we need to create a spil
692 location on the stack , for which one? the least
694 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
697 /* return a created spil location */
698 sym = createStackSpil (leastUsedLR (selectS));
699 sym->usl.spillLoc->allocreq++;
703 /* this is an extreme situation we will spill
704 this one : happens very rarely but it does happen */
710 /*-----------------------------------------------------------------*/
711 /* spilSomething - spil some variable & mark registers as free */
712 /*-----------------------------------------------------------------*/
714 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
719 /* get something we can spil */
720 ssym = selectSpil (ic, ebp, forSym);
722 /* mark it as spilt */
723 ssym->isspilt = ssym->spillA = 1;
724 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
726 /* mark it as not register assigned &
727 take it away from the set */
728 bitVectUnSetBit (_G.regAssigned, ssym->key);
729 bitVectUnSetBit (_G.totRegAssigned, ssym->key);
731 /* mark the registers as free */
732 for (i = 0; i < ssym->nRegs; i++)
734 freeReg (ssym->regs[i]);
736 /* if spilt on stack then free up r0 & r1
737 if they could have been assigned to as gprs */
738 if (!mcs51_ptrRegReq && isSpiltOnStack (ssym))
741 spillLRWithPtrReg (ssym);
744 /* if this was a block level spil then insert push & pop
745 at the start & end of block respectively */
748 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
749 /* add push to the start of the block */
750 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
751 ebp->sch->next : ebp->sch));
752 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
753 /* add pop to the end of the block */
754 addiCodeToeBBlock (ebp, nic, NULL);
757 /* if spilt because not used in the remainder of the
758 block then add a push before this instruction and
759 a pop at the end of the block */
760 if (ssym->remainSpil)
763 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
764 /* add push just before this instruction */
765 addiCodeToeBBlock (ebp, nic, ic);
767 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
768 /* add pop to the end of the block */
769 addiCodeToeBBlock (ebp, nic, NULL);
778 /*-----------------------------------------------------------------*/
779 /* getRegPtr - will try for PTR if not a GPR type if not spil */
780 /*-----------------------------------------------------------------*/
782 getRegPtr (iCode * ic, eBBlock * ebp, symbol * sym)
787 /* try for a ptr type */
788 if ((reg = allocReg (REG_PTR)))
791 /* try for gpr type */
792 if ((reg = allocReg (REG_GPR)))
795 /* we have to spil */
796 if (!spilSomething (ic, ebp, sym))
799 /* this looks like an infinite loop but
800 in really selectSpil will abort */
804 /*-----------------------------------------------------------------*/
805 /* getRegGpr - will try for GPR if not spil */
806 /*-----------------------------------------------------------------*/
808 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
813 /* try for gpr type */
814 if ((reg = allocReg (REG_GPR)))
817 if (!mcs51_ptrRegReq)
818 if ((reg = allocReg (REG_PTR)))
821 /* we have to spil */
822 if (!spilSomething (ic, ebp, sym))
825 /* this looks like an infinite loop but
826 in really selectSpil will abort */
830 /*-----------------------------------------------------------------*/
831 /* getRegPtrNoSpil - get it cannot split */
832 /*-----------------------------------------------------------------*/
833 static regs *getRegPtrNoSpil()
837 /* try for a ptr type */
838 if ((reg = allocReg (REG_PTR)))
841 /* try for gpr type */
842 if ((reg = allocReg (REG_GPR)))
847 /* just to make the compiler happy */
851 /*-----------------------------------------------------------------*/
852 /* getRegGprNoSpil - get it cannot split */
853 /*-----------------------------------------------------------------*/
854 static regs *getRegGprNoSpil()
858 if ((reg = allocReg (REG_GPR)))
861 if (!mcs51_ptrRegReq)
862 if ((reg = allocReg (REG_PTR)))
867 /* just to make the compiler happy */
871 /*-----------------------------------------------------------------*/
872 /* symHasReg - symbol has a given register */
873 /*-----------------------------------------------------------------*/
875 symHasReg (symbol * sym, regs * reg)
879 for (i = 0; i < sym->nRegs; i++)
880 if (sym->regs[i] == reg)
886 /*-----------------------------------------------------------------*/
887 /* deassignLRs - check the live to and if they have registers & are */
888 /* not spilt then free up the registers */
889 /*-----------------------------------------------------------------*/
891 deassignLRs (iCode * ic, eBBlock * ebp)
897 for (sym = hTabFirstItem (liveRanges, &k); sym;
898 sym = hTabNextItem (liveRanges, &k))
902 /* if it does not end here */
903 if (sym->liveTo > ic->seq)
906 /* if it was spilt on stack then we can
907 mark the stack spil location as free */
912 sym->usl.spillLoc->isFree = 1;
918 if (!bitVectBitValue (_G.regAssigned, sym->key))
921 /* special case check if this is an IFX &
922 the privious one was a pop and the
923 previous one was not spilt then keep track
925 if (ic->op == IFX && ic->prev &&
926 ic->prev->op == IPOP &&
927 !ic->prev->parmPush &&
928 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
929 psym = OP_SYMBOL (IC_LEFT (ic->prev));
935 bitVectUnSetBit (_G.regAssigned, sym->key);
937 /* if the result of this one needs registers
938 and does not have it then assign it right
940 if (IC_RESULT (ic) &&
941 !(SKIP_IC2 (ic) || /* not a special icode */
942 ic->op == JUMPTABLE ||
948 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
949 result->liveTo > ic->seq && /* and will live beyond this */
950 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
951 result->regType == sym->regType && /* same register types */
952 result->nRegs && /* which needs registers */
953 !result->isspilt && /* and does not already have them */
955 !bitVectBitValue (_G.regAssigned, result->key) &&
956 /* the number of free regs + number of regs in this LR
957 can accomodate the what result Needs */
958 ((nfreeRegsType (result->regType) +
959 sym->nRegs) >= result->nRegs)
963 for (i = 0; i < result->nRegs; i++)
965 result->regs[i] = sym->regs[i];
967 result->regs[i] = getRegGpr (ic, ebp, result);
969 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
970 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, result->key);
974 /* free the remaining */
975 for (; i < sym->nRegs; i++)
979 if (!symHasReg (psym, sym->regs[i]))
980 freeReg (sym->regs[i]);
983 freeReg (sym->regs[i]);
990 /*-----------------------------------------------------------------*/
991 /* reassignLR - reassign this to registers */
992 /*-----------------------------------------------------------------*/
994 reassignLR (operand * op)
996 symbol *sym = OP_SYMBOL (op);
999 /* not spilt any more */
1000 sym->isspilt = sym->spillA = sym->blockSpil = sym->remainSpil = 0;
1001 bitVectUnSetBit (_G.spiltSet, sym->key);
1003 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1004 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, sym->key);
1008 for (i = 0; i < sym->nRegs; i++)
1009 sym->regs[i]->isFree = 0;
1012 /*-----------------------------------------------------------------*/
1013 /* willCauseSpill - determines if allocating will cause a spill */
1014 /*-----------------------------------------------------------------*/
1016 willCauseSpill (int nr, int rt)
1018 /* first check if there are any avlb registers
1019 of te type required */
1022 /* special case for pointer type
1023 if pointer type not avlb then
1024 check for type gpr */
1025 if (nFreeRegs (rt) >= nr)
1027 if (nFreeRegs (REG_GPR) >= nr)
1032 if (mcs51_ptrRegReq)
1034 if (nFreeRegs (rt) >= nr)
1039 if (nFreeRegs (REG_PTR) +
1040 nFreeRegs (REG_GPR) >= nr)
1045 /* it will cause a spil */
1049 /*-----------------------------------------------------------------*/
1050 /* positionRegs - the allocator can allocate same registers to res- */
1051 /* ult and operand, if this happens make sure they are in the same */
1052 /* position as the operand otherwise chaos results */
1053 /*-----------------------------------------------------------------*/
1055 positionRegs (symbol * result, symbol * opsym)
1057 int count = min (result->nRegs, opsym->nRegs);
1058 int i, j = 0, shared = 0;
1061 /* if the result has been spilt then cannot share */
1066 /* first make sure that they actually share */
1067 for (i = 0; i < count; i++)
1069 for (j = 0; j < count; j++)
1071 if (result->regs[i] == opsym->regs[j] && i != j)
1081 regs *tmp = result->regs[i];
1082 result->regs[i] = result->regs[j];
1083 result->regs[j] = tmp;
1090 /*-----------------------------------------------------------------*/
1091 /* serialRegAssign - serially allocate registers to the variables */
1092 /*-----------------------------------------------------------------*/
1094 serialRegAssign (eBBlock ** ebbs, int count)
1098 /* for all blocks */
1099 for (i = 0; i < count; i++) {
1103 if (ebbs[i]->noPath &&
1104 (ebbs[i]->entryLabel != entryLabel &&
1105 ebbs[i]->entryLabel != returnLabel))
1108 /* of all instructions do */
1109 for (ic = ebbs[i]->sch; ic; ic = ic->next) {
1112 // update the registers in use at the start of this icode
1113 for (i=0; i<8; i++) {
1114 if (regs8051[i].isFree) {
1115 ic->riu &= ~(1<<regs8051[i].offset);
1117 ic->riu |= (1<<regs8051[i].offset);
1121 /* if this is an ipop that means some live
1122 range will have to be assigned again */
1124 reassignLR (IC_LEFT (ic));
1126 /* if result is present && is a true symbol */
1127 if (IC_RESULT (ic) && ic->op != IFX &&
1128 IS_TRUE_SYMOP (IC_RESULT (ic)))
1129 OP_SYMBOL (IC_RESULT (ic))->allocreq++;
1131 /* take away registers from live
1132 ranges that end at this instruction */
1133 deassignLRs (ic, ebbs[i]);
1135 /* some don't need registers */
1136 if (SKIP_IC2 (ic) ||
1137 ic->op == JUMPTABLE ||
1141 (IC_RESULT (ic) && POINTER_SET (ic)))
1144 /* now we need to allocate registers
1145 only for the result */
1146 if (IC_RESULT (ic)) {
1147 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1153 /* if it does not need or is spilt
1154 or is already assigned to registers
1155 or will not live beyond this instructions */
1158 bitVectBitValue (_G.regAssigned, sym->key) ||
1159 sym->liveTo <= ic->seq)
1162 /* if some liverange has been spilt at the block level
1163 and this one live beyond this block then spil this
1165 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1169 /* if trying to allocate this will cause
1170 a spill and there is nothing to spill
1171 or this one is rematerializable then
1173 willCS = willCauseSpill (sym->nRegs, sym->regType);
1174 spillable = computeSpillable (ic);
1175 if (sym->remat || (willCS && bitVectIsZero (spillable))) {
1180 /* if it has a spillocation & is used less than
1181 all other live ranges then spill this */
1183 if (sym->usl.spillLoc) {
1184 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1185 allLRs, ebbs[i], ic));
1186 if (leastUsed && leastUsed->used > sym->used) {
1191 /* if none of the liveRanges have a spillLocation then better
1192 to spill this one than anything else already assigned to registers */
1193 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1194 /* if this is local to this block then we might find a block spil */
1195 if (!(sym->liveFrom >= ebbs[i]->fSeq && sym->liveTo <= ebbs[i]->lSeq)) {
1202 /* if we need ptr regs for the right side
1204 if (POINTER_GET (ic) && IS_SYMOP (IC_LEFT (ic))
1205 && getSize (OP_SYMBOL (IC_LEFT (ic))->type) <= (unsigned int) PTRSIZE) {
1209 /* else we assign registers to it */
1210 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1211 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, sym->key);
1213 for (j = 0; j < sym->nRegs; j++) {
1214 if (sym->regType == REG_PTR)
1215 sym->regs[j] = getRegPtr (ic, ebbs[i], sym);
1217 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1219 /* if the allocation failed which means
1220 this was spilt then break */
1221 if (!sym->regs[j]) {
1226 /* if it shares registers with operands make sure
1227 that they are in the same position */
1228 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1229 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=') {
1230 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1231 OP_SYMBOL (IC_LEFT (ic)));
1233 /* do the same for the right operand */
1234 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1235 OP_SYMBOL (IC_RIGHT (ic))->nRegs) {
1236 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1237 OP_SYMBOL (IC_RIGHT (ic)));
1250 /*-----------------------------------------------------------------*/
1251 /* fillGaps - Try to fill in the Gaps left by Pass1 */
1252 /*-----------------------------------------------------------------*/
1253 static void fillGaps()
1258 if (getenv("DISABLE_FILL_GAPS")) return;
1260 /* look for livernages that was spilt by the allocator */
1261 for (sym = hTabFirstItem(liveRanges,&key) ; sym ;
1262 sym = hTabNextItem(liveRanges,&key)) {
1267 if (!sym->spillA || !sym->clashes || sym->remat) continue ;
1269 /* find the liveRanges this one clashes with, that are
1270 still assigned to registers & mark the registers as used*/
1271 for ( i = 0 ; i < sym->clashes->size ; i ++) {
1275 if (bitVectBitValue(sym->clashes,i) == 0 || /* those that clash with this */
1276 bitVectBitValue(_G.totRegAssigned,i) == 0) /* and are still assigned to registers */
1279 clr = hTabItemWithKey(liveRanges,i);
1282 /* mark these registers as used */
1283 for (k = 0 ; k < clr->nRegs ; k++ )
1284 useReg(clr->regs[k]);
1287 if (willCauseSpill(sym->nRegs,sym->regType)) {
1288 /* NOPE :( clear all registers & and continue */
1293 /* THERE IS HOPE !!!! */
1294 for (i=0; i < sym->nRegs ; i++ ) {
1295 if (sym->regType == REG_PTR)
1296 sym->regs[i] = getRegPtrNoSpil ();
1298 sym->regs[i] = getRegGprNoSpil ();
1301 /* for all its definitions check if the registers
1302 allocated needs positioning NOTE: we can position
1303 only ONCE if more than One positioning required
1306 for (i = 0 ; i < sym->defs->size ; i++ ) {
1307 if (bitVectBitValue(sym->defs,i)) {
1309 if (!(ic = hTabItemWithKey(iCodehTab,i))) continue ;
1310 if (SKIP_IC(ic)) continue;
1311 assert(isSymbolEqual(sym,OP_SYMBOL(IC_RESULT(ic)))); /* just making sure */
1312 /* if left is assigned to registers */
1313 if (IS_SYMOP(IC_LEFT(ic)) &&
1314 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_LEFT(ic))->key)) {
1315 pdone += positionRegs(sym,OP_SYMBOL(IC_LEFT(ic)));
1317 if (IS_SYMOP(IC_RIGHT(ic)) &&
1318 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_RIGHT(ic))->key)) {
1319 pdone += positionRegs(sym,OP_SYMBOL(IC_RIGHT(ic)));
1321 if (pdone > 1) break;
1324 for (i = 0 ; i < sym->uses->size ; i++ ) {
1325 if (bitVectBitValue(sym->uses,i)) {
1327 if (!(ic = hTabItemWithKey(iCodehTab,i))) continue ;
1328 if (SKIP_IC(ic)) continue;
1329 if (!IS_ASSIGN_ICODE(ic)) continue ;
1331 /* if result is assigned to registers */
1332 if (IS_SYMOP(IC_RESULT(ic)) &&
1333 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_RESULT(ic))->key)) {
1334 pdone += positionRegs(sym,OP_SYMBOL(IC_RESULT(ic)));
1336 if (pdone > 1) break;
1339 /* had to position more than once GIVE UP */
1341 /* UNDO all the changes we made to try this */
1343 for (i=0; i < sym->nRegs ; i++ ) {
1344 sym->regs[i] = NULL;
1347 D(printf ("Fill Gap gave up due to positioning for %s in function %s\n",sym->name, currFunc ? currFunc->name : "UNKNOWN"));
1350 D(printf ("FILLED GAP for %s in function %s\n",sym->name, currFunc ? currFunc->name : "UNKNOWN"));
1351 _G.totRegAssigned = bitVectSetBit(_G.totRegAssigned,sym->key);
1352 sym->isspilt = sym->spillA = 0 ;
1353 sym->usl.spillLoc->allocreq--;
1358 /*-----------------------------------------------------------------*/
1359 /* rUmaskForOp :- returns register mask for an operand */
1360 /*-----------------------------------------------------------------*/
1362 mcs51_rUmaskForOp (operand * op)
1368 /* only temporaries are assigned registers */
1372 sym = OP_SYMBOL (op);
1374 /* if spilt or no registers assigned to it
1376 if (sym->isspilt || !sym->nRegs)
1379 rumask = newBitVect (mcs51_nRegs);
1381 for (j = 0; j < sym->nRegs; j++)
1383 rumask = bitVectSetBit (rumask,
1384 sym->regs[j]->rIdx);
1390 /*-----------------------------------------------------------------*/
1391 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1392 /*-----------------------------------------------------------------*/
1394 regsUsedIniCode (iCode * ic)
1396 bitVect *rmask = newBitVect (mcs51_nRegs);
1398 /* do the special cases first */
1401 rmask = bitVectUnion (rmask,
1402 mcs51_rUmaskForOp (IC_COND (ic)));
1406 /* for the jumptable */
1407 if (ic->op == JUMPTABLE)
1409 rmask = bitVectUnion (rmask,
1410 mcs51_rUmaskForOp (IC_JTCOND (ic)));
1415 /* of all other cases */
1417 rmask = bitVectUnion (rmask,
1418 mcs51_rUmaskForOp (IC_LEFT (ic)));
1422 rmask = bitVectUnion (rmask,
1423 mcs51_rUmaskForOp (IC_RIGHT (ic)));
1426 rmask = bitVectUnion (rmask,
1427 mcs51_rUmaskForOp (IC_RESULT (ic)));
1433 /*-----------------------------------------------------------------*/
1434 /* createRegMask - for each instruction will determine the regsUsed */
1435 /*-----------------------------------------------------------------*/
1437 createRegMask (eBBlock ** ebbs, int count)
1441 /* for all blocks */
1442 for (i = 0; i < count; i++)
1446 if (ebbs[i]->noPath &&
1447 (ebbs[i]->entryLabel != entryLabel &&
1448 ebbs[i]->entryLabel != returnLabel))
1451 /* for all instructions */
1452 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1457 if (SKIP_IC2 (ic) || !ic->rlive)
1460 /* first mark the registers used in this
1462 ic->rUsed = regsUsedIniCode (ic);
1463 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1465 /* now create the register mask for those
1466 registers that are in use : this is a
1467 super set of ic->rUsed */
1468 ic->rMask = newBitVect (mcs51_nRegs + 1);
1470 /* for all live Ranges alive at this point */
1471 for (j = 1; j < ic->rlive->size; j++)
1476 /* if not alive then continue */
1477 if (!bitVectBitValue (ic->rlive, j))
1480 /* find the live range we are interested in */
1481 if (!(sym = hTabItemWithKey (liveRanges, j)))
1483 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1484 "createRegMask cannot find live range");
1485 fprintf(stderr, "\tmissing live range: key=%d\n", j);
1489 /* if no register assigned to it */
1490 if (!sym->nRegs || sym->isspilt)
1493 /* for all the registers allocated to it */
1494 for (k = 0; k < sym->nRegs; k++)
1497 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1503 /*-----------------------------------------------------------------*/
1504 /* rematStr - returns the rematerialized string for a remat var */
1505 /*-----------------------------------------------------------------*/
1507 rematStr (symbol * sym)
1510 iCode *ic = sym->rematiCode;
1515 /* if plus or minus print the right hand side */
1516 if (ic->op == '+' || ic->op == '-')
1518 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1521 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1525 /* cast then continue */
1526 if (IS_CAST_ICODE(ic)) {
1527 ic = OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
1530 /* we reached the end */
1531 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1538 /*-----------------------------------------------------------------*/
1539 /* regTypeNum - computes the type & number of registers required */
1540 /*-----------------------------------------------------------------*/
1542 regTypeNum (eBBlock *ebbs)
1548 /* for each live range do */
1549 for (sym = hTabFirstItem (liveRanges, &k); sym;
1550 sym = hTabNextItem (liveRanges, &k))
1553 /* if used zero times then no registers needed */
1554 if ((sym->liveTo - sym->liveFrom) == 0)
1558 /* if the live range is a temporary */
1562 /* if the type is marked as a conditional */
1563 if (sym->regType == REG_CND)
1566 /* if used in return only then we don't
1568 if (sym->ruonly || sym->accuse)
1570 if (IS_AGGREGATE (sym->type) || sym->isptr)
1571 sym->type = aggrToPtr (sym->type, FALSE);
1576 /* if this symbol has only one usage and that is an assignment
1577 to a ruonly, we don't need registers */
1578 // if this symbol has only one def
1579 if (bitVectnBitsOn (sym->defs)==1) {
1580 printf ("sym: %s has only one usage", sym->name);
1582 if ((ic = hTabItemWithKey (iCodehTab, bitVectFirstBit (sym->defs)))) {
1584 printf (" for a call ");
1585 // if this is only assigned to a ruonly
1586 if ((ic = hTabItemWithKey (iCodehTab, bitVectFirstBit (sym->defs)))) {
1588 if (OP_SYMBOL(IC_RESULT(ic))->ruonly) {
1589 printf("regTypeNum: %s assigned to %s\n", \
1590 sym->name, OP_SYMBOL(IC_RESULT(ic))->name);
1599 /* if the symbol has only one definition &
1600 that definition is a get_pointer */
1601 if (bitVectnBitsOn (sym->defs) == 1 &&
1602 (ic = hTabItemWithKey (iCodehTab,
1603 bitVectFirstBit (sym->defs))) &&
1606 !IS_BITVAR (sym->etype))
1610 /* and that pointer is remat in data space */
1611 if (IS_SYMOP (IC_LEFT (ic)) &&
1612 OP_SYMBOL (IC_LEFT (ic))->remat &&
1613 !IS_CAST_ICODE(OP_SYMBOL (IC_LEFT (ic))->rematiCode) &&
1614 DCL_TYPE (aggrToPtr (operandType(IC_LEFT(ic)), FALSE)) == POINTER)
1616 /* create a psuedo symbol & force a spil */
1617 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1618 psym->type = sym->type;
1619 psym->etype = sym->etype;
1620 strcpy (psym->rname, psym->name);
1622 sym->usl.spillLoc = psym;
1623 #if 0 // an alternative fix for bug #480076
1624 /* now this is a useless assignment to itself */
1625 remiCodeFromeBBlock (ebbs, ic);
1627 /* now this really is an assignment to itself, make it so;
1628 it will be optimized out later */
1630 ReplaceOpWithCheaperOp(&IC_RIGHT(ic), IC_RESULT(ic));
1636 /* if in data space or idata space then try to
1637 allocate pointer register */
1641 /* if not then we require registers */
1642 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1643 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1644 getSize (sym->type));
1648 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1649 printTypeChain (sym->type, stderr);
1650 fprintf (stderr, "\n");
1653 /* determine the type of register required */
1654 if (sym->nRegs == 1 &&
1655 IS_PTR (sym->type) &&
1657 sym->regType = REG_PTR;
1659 sym->regType = REG_GPR;
1663 /* for the first run we don't provide */
1664 /* registers for true symbols we will */
1665 /* see how things go */
1671 /*-----------------------------------------------------------------*/
1672 /* freeAllRegs - mark all registers as free */
1673 /*-----------------------------------------------------------------*/
1679 for (i = 0; i < mcs51_nRegs; i++)
1680 regs8051[i].isFree = 1;
1683 /*-----------------------------------------------------------------*/
1684 /* deallocStackSpil - this will set the stack pointer back */
1685 /*-----------------------------------------------------------------*/
1687 DEFSETFUNC (deallocStackSpil)
1695 /*-----------------------------------------------------------------*/
1696 /* farSpacePackable - returns the packable icode for far variables */
1697 /*-----------------------------------------------------------------*/
1699 farSpacePackable (iCode * ic)
1703 /* go thru till we find a definition for the
1704 symbol on the right */
1705 for (dic = ic->prev; dic; dic = dic->prev)
1707 /* if the definition is a call then no */
1708 if ((dic->op == CALL || dic->op == PCALL) &&
1709 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1714 /* if shift by unknown amount then not */
1715 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1716 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1719 /* if pointer get and size > 1 */
1720 if (POINTER_GET (dic) &&
1721 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1724 if (POINTER_SET (dic) &&
1725 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1728 /* if any three is a true symbol in far space */
1729 if (IC_RESULT (dic) &&
1730 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1731 isOperandInFarSpace (IC_RESULT (dic)))
1734 if (IC_RIGHT (dic) &&
1735 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1736 isOperandInFarSpace (IC_RIGHT (dic)) &&
1737 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1740 if (IC_LEFT (dic) &&
1741 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1742 isOperandInFarSpace (IC_LEFT (dic)) &&
1743 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1746 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1748 if ((dic->op == LEFT_OP ||
1749 dic->op == RIGHT_OP ||
1751 IS_OP_LITERAL (IC_RIGHT (dic)))
1761 /*-----------------------------------------------------------------*/
1762 /* packRegsForAssign - register reduction for assignment */
1763 /*-----------------------------------------------------------------*/
1765 packRegsForAssign (iCode * ic, eBBlock * ebp)
1769 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1770 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1771 OP_LIVETO (IC_RIGHT (ic)) > ic->seq)
1777 /* if the true symbol is defined in far space or on stack
1778 then we should not since this will increase register pressure */
1779 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1783 /* find the definition of iTempNN scanning backwards if we find a
1784 a use of the true symbol in before we find the definition then
1786 for (dic = ic->prev; dic; dic = dic->prev)
1788 /* if there is a function call then don't pack it */
1789 if ((dic->op == CALL || dic->op == PCALL))
1798 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1799 IS_OP_VOLATILE (IC_RESULT (dic)))
1805 if (IS_SYMOP (IC_RESULT (dic)) &&
1806 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1808 if (POINTER_SET (dic))
1814 if (IS_SYMOP (IC_RIGHT (dic)) &&
1815 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1816 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1822 if (IS_SYMOP (IC_LEFT (dic)) &&
1823 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1824 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1830 if (POINTER_SET (dic) &&
1831 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1839 return 0; /* did not find */
1841 /* if assignment then check that right is not a bit */
1842 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1844 sym_link *etype = operandType (IC_RIGHT (dic));
1845 if (IS_BITFIELD (etype))
1847 /* if result is a bit too then it's ok */
1848 etype = operandType (IC_RESULT (dic));
1849 if (!IS_BITFIELD (etype))
1853 /* if the result is on stack or iaccess then it must be
1854 the same atleast one of the operands */
1855 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1856 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1859 /* the operation has only one symbol
1860 operator then we can pack */
1861 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1862 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1865 if (!((IC_LEFT (dic) &&
1866 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1868 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1872 /* found the definition */
1873 /* replace the result with the result of */
1874 /* this assignment and remove this assignment */
1875 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
1876 ReplaceOpWithCheaperOp(&IC_RESULT (dic), IC_RESULT (ic));
1878 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1880 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1882 // TODO: and the otherway around?
1884 /* delete from liverange table also
1885 delete from all the points inbetween and the new
1887 for (sic = dic; sic != ic; sic = sic->next)
1889 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1890 if (IS_ITEMP (IC_RESULT (dic)))
1891 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1894 remiCodeFromeBBlock (ebp, ic);
1895 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
1896 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1897 OP_DEFS(IC_RESULT (dic))=bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1901 /*------------------------------------------------------------------*/
1902 /* findAssignToSym : scanning backwards looks for first assig found */
1903 /*------------------------------------------------------------------*/
1905 findAssignToSym (operand * op, iCode * ic)
1909 /* This routine is used to find sequences like
1911 ...; (intervening ops don't use iTempAA or modify FOO)
1912 blah = blah + iTempAA;
1914 and eliminate the use of iTempAA, freeing up its register for
1919 for (dic = ic->prev; dic; dic = dic->prev)
1922 /* if definition by assignment */
1923 if (dic->op == '=' &&
1924 !POINTER_SET (dic) &&
1925 IC_RESULT (dic)->key == op->key
1926 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1928 break; /* found where this temp was defined */
1930 /* if we find an usage then we cannot delete it */
1931 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1934 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1937 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1942 return NULL; /* didn't find any assignment to op */
1944 /* we are interested only if defined in far space */
1945 /* or in stack space in case of + & - */
1947 /* if assigned to a non-symbol then don't repack regs */
1948 if (!IS_SYMOP (IC_RIGHT (dic)))
1951 /* if the symbol is volatile then we should not */
1952 if (isOperandVolatile (IC_RIGHT (dic), TRUE))
1954 /* XXX TODO --- should we be passing FALSE to isOperandVolatile()?
1955 What does it mean for an iTemp to be volatile, anyway? Passing
1956 TRUE is more cautious but may prevent possible optimizations */
1958 /* if the symbol is in far space then we should not */
1959 if (isOperandInFarSpace (IC_RIGHT (dic)))
1962 /* for + & - operations make sure that
1963 if it is on the stack it is the same
1964 as one of the three operands */
1965 if ((ic->op == '+' || ic->op == '-') &&
1966 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1969 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1970 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1971 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1975 /* now make sure that the right side of dic
1976 is not defined between ic & dic */
1979 iCode *sic = dic->next;
1981 for (; sic != ic; sic = sic->next)
1982 if (IC_RESULT (sic) &&
1983 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1990 /*-----------------------------------------------------------------*/
1991 /* reassignAliasedSym - used by packRegsForSupport to replace */
1992 /* redundant iTemp with equivalent symbol */
1993 /*-----------------------------------------------------------------*/
1995 reassignAliasedSym (eBBlock *ebp, iCode *assignment, iCode *use, operand *op)
1998 unsigned oldSymKey, newSymKey;
2000 oldSymKey = op->key;
2001 newSymKey = IC_RIGHT(assignment)->key;
2003 /* only track live ranges of compiler-generated temporaries */
2004 if (!IS_ITEMP(IC_RIGHT(assignment)))
2007 /* update the live-value bitmaps */
2008 for (ic = assignment; ic != use; ic = ic->next) {
2009 bitVectUnSetBit (ic->rlive, oldSymKey);
2011 ic->rlive = bitVectSetBit (ic->rlive, newSymKey);
2014 /* update the sym of the used operand */
2015 OP_SYMBOL(op) = OP_SYMBOL(IC_RIGHT(assignment));
2016 op->key = OP_SYMBOL(op)->key;
2018 /* update the sym's liverange */
2019 if ( OP_LIVETO(op) < ic->seq )
2020 setToRange(op, ic->seq, FALSE);
2022 /* remove the assignment iCode now that its result is unused */
2023 remiCodeFromeBBlock (ebp, assignment);
2024 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(assignment))->defs, assignment->key);
2025 hTabDeleteItem (&iCodehTab, assignment->key, assignment, DELETE_ITEM, NULL);
2029 /*-----------------------------------------------------------------*/
2030 /* packRegsForSupport :- reduce some registers for support calls */
2031 /*-----------------------------------------------------------------*/
2033 packRegsForSupport (iCode * ic, eBBlock * ebp)
2037 /* for the left & right operand :- look to see if the
2038 left was assigned a true symbol in far space in that
2039 case replace them */
2041 if (IS_ITEMP (IC_LEFT (ic)) &&
2042 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
2044 dic = findAssignToSym (IC_LEFT (ic), ic);
2048 /* found it we need to remove it from the block */
2049 reassignAliasedSym (ebp, dic, ic, IC_LEFT(ic));
2054 /* do the same for the right operand */
2055 if (IS_ITEMP (IC_RIGHT (ic)) &&
2056 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
2058 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
2062 /* if this is a subtraction & the result
2063 is a true symbol in far space then don't pack */
2064 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
2066 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
2067 if (IN_FARSPACE (SPEC_OCLS (etype)))
2070 /* found it we need to remove it from the
2072 reassignAliasedSym (ebp, dic, ic, IC_RIGHT(ic));
2081 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
2084 /*-----------------------------------------------------------------*/
2085 /* packRegsForOneuse : - will reduce some registers for single Use */
2086 /*-----------------------------------------------------------------*/
2088 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
2093 /* if returning a literal then do nothing */
2097 /* only upto 2 bytes since we cannot predict
2098 the usage of b, & acc */
2099 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
2102 if (ic->op != RETURN &&
2104 !POINTER_SET (ic) &&
2108 if (ic->op == SEND && ic->argreg != 1) return NULL;
2110 /* this routine will mark the a symbol as used in one
2111 instruction use only && if the defintion is local
2112 (ie. within the basic block) && has only one definition &&
2113 that definiion is either a return value from a
2114 function or does not contain any variables in
2116 uses = bitVectCopy (OP_USES (op));
2117 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
2118 if (!bitVectIsZero (uses)) /* has other uses */
2121 /* if it has only one defintion */
2122 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
2123 return NULL; /* has more than one definition */
2125 /* get that definition */
2127 hTabItemWithKey (iCodehTab,
2128 bitVectFirstBit (OP_DEFS (op)))))
2131 /* if that only usage is a cast */
2132 if (dic->op == CAST) {
2133 /* to a bigger type */
2134 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
2135 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
2136 /* than we can not, since we cannot predict the usage of b & acc */
2141 /* found the definition now check if it is local */
2142 if (dic->seq < ebp->fSeq ||
2143 dic->seq > ebp->lSeq)
2144 return NULL; /* non-local */
2146 /* now check if it is the return from
2148 if (dic->op == CALL || dic->op == PCALL)
2150 if (ic->op != SEND && ic->op != RETURN &&
2151 !POINTER_SET(ic) && !POINTER_GET(ic))
2153 OP_SYMBOL (op)->ruonly = 1;
2160 /* otherwise check that the definition does
2161 not contain any symbols in far space */
2162 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2163 isOperandInFarSpace (IC_RIGHT (dic)) ||
2164 IS_OP_RUONLY (IC_LEFT (ic)) ||
2165 IS_OP_RUONLY (IC_RIGHT (ic)))
2170 /* if pointer set then make sure the pointer
2172 if (POINTER_SET (dic) &&
2173 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
2176 if (POINTER_GET (dic) &&
2177 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
2182 /* also make sure the intervenening instructions
2183 don't have any thing in far space */
2184 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
2187 /* if there is an intervening function call then no */
2188 if (dic->op == CALL || dic->op == PCALL)
2190 /* if pointer set then make sure the pointer
2192 if (POINTER_SET (dic) &&
2193 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
2196 if (POINTER_GET (dic) &&
2197 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
2200 /* if address of & the result is remat the okay */
2201 if (dic->op == ADDRESS_OF &&
2202 OP_SYMBOL (IC_RESULT (dic))->remat)
2205 /* if operand has size of three or more & this
2206 operation is a '*','/' or '%' then 'b' may
2208 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
2209 getSize (operandType (op)) >= 3)
2212 /* if left or right or result is in far space */
2213 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2214 isOperandInFarSpace (IC_RIGHT (dic)) ||
2215 isOperandInFarSpace (IC_RESULT (dic)) ||
2216 IS_OP_RUONLY (IC_LEFT (dic)) ||
2217 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2218 IS_OP_RUONLY (IC_RESULT (dic)))
2222 /* if left or right or result is on stack */
2223 if (isOperandOnStack(IC_LEFT(dic)) ||
2224 isOperandOnStack(IC_RIGHT(dic)) ||
2225 isOperandOnStack(IC_RESULT(dic))) {
2230 OP_SYMBOL (op)->ruonly = 1;
2234 /*-----------------------------------------------------------------*/
2235 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2236 /*-----------------------------------------------------------------*/
2238 isBitwiseOptimizable (iCode * ic)
2240 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2241 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2243 /* bitwise operations are considered optimizable
2244 under the following conditions (Jean-Louis VERN)
2256 if (IS_LITERAL(rtype) ||
2257 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2263 /*-----------------------------------------------------------------*/
2264 /* isCommutativeOp - tests whether this op cares what order its */
2265 /* operands are in */
2266 /*-----------------------------------------------------------------*/
2267 bool isCommutativeOp(unsigned int op)
2269 if (op == '+' || op == '*' || op == EQ_OP ||
2270 op == '^' || op == '|' || op == BITWISEAND)
2276 /*-----------------------------------------------------------------*/
2277 /* operandUsesAcc - determines whether the code generated for this */
2278 /* operand will have to use the accumulator */
2279 /*-----------------------------------------------------------------*/
2280 bool operandUsesAcc(operand *op)
2286 symbol *sym = OP_SYMBOL(op);
2290 return TRUE; /* duh! */
2292 if (IN_STACK(sym->etype) || sym->onStack ||
2293 (SPIL_LOC(op) && SPIL_LOC(op)->onStack))
2294 return TRUE; /* acc is used to calc stack offset */
2299 sym = SPIL_LOC(op); /* if spilled, look at spill location */
2301 return FALSE; /* more checks? */
2305 symspace = SPEC_OCLS(sym->etype);
2307 if (sym->iaccess && symspace->paged)
2308 return TRUE; /* must fetch paged indirect sym via accumulator */
2310 if (IN_BITSPACE(symspace))
2311 return TRUE; /* fetching bit vars uses the accumulator */
2313 if (IN_FARSPACE(symspace) || IN_CODESPACE(symspace))
2314 return TRUE; /* fetched via accumulator and dptr */
2320 /*-----------------------------------------------------------------*/
2321 /* packRegsForAccUse - pack registers for acc use */
2322 /*-----------------------------------------------------------------*/
2324 packRegsForAccUse (iCode * ic)
2328 /* if this is an aggregate, e.g. a one byte char array */
2329 if (IS_AGGREGATE(operandType(IC_RESULT(ic)))) {
2333 /* if we are calling a reentrant function that has stack parameters */
2334 if (ic->op == CALL &&
2335 IFFUNC_ISREENT(operandType(IC_LEFT(ic))) &&
2336 FUNC_HASSTACKPARM(operandType(IC_LEFT(ic))))
2339 if (ic->op == PCALL &&
2340 IFFUNC_ISREENT(operandType(IC_LEFT(ic))->next) &&
2341 FUNC_HASSTACKPARM(operandType(IC_LEFT(ic))->next))
2344 /* if + or - then it has to be one byte result */
2345 if ((ic->op == '+' || ic->op == '-')
2346 && getSize (operandType (IC_RESULT (ic))) > 1)
2349 /* if shift operation make sure right side is not a literal */
2350 if (ic->op == RIGHT_OP &&
2351 (isOperandLiteral (IC_RIGHT (ic)) ||
2352 getSize (operandType (IC_RESULT (ic))) > 1))
2355 if (ic->op == LEFT_OP &&
2356 (isOperandLiteral (IC_RIGHT (ic)) ||
2357 getSize (operandType (IC_RESULT (ic))) > 1))
2360 if (IS_BITWISE_OP (ic) &&
2361 getSize (operandType (IC_RESULT (ic))) > 1)
2365 /* has only one definition */
2366 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2369 /* has only one use */
2370 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2373 /* and the usage immediately follows this iCode */
2374 if (!(uic = hTabItemWithKey (iCodehTab,
2375 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2378 if (ic->next != uic)
2381 /* if it is a conditional branch then we definitely can */
2385 if (uic->op == JUMPTABLE)
2388 if (POINTER_SET (uic) &&
2389 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2392 /* if the usage is not is an assignment
2393 or an arithmetic / bitwise / shift operation then not */
2394 if (uic->op != '=' &&
2395 !IS_ARITHMETIC_OP (uic) &&
2396 !IS_BITWISE_OP (uic) &&
2397 uic->op != LEFT_OP &&
2398 uic->op != RIGHT_OP)
2401 /* if used in ^ operation then make sure right is not a
2402 literal (WIML: Why is this?) */
2403 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2406 /* if shift operation make sure right side is not a literal */
2407 /* WIML: Why is this? */
2408 if (uic->op == RIGHT_OP &&
2409 (isOperandLiteral (IC_RIGHT (uic)) ||
2410 getSize (operandType (IC_RESULT (uic))) > 1))
2412 if (uic->op == LEFT_OP &&
2413 (isOperandLiteral (IC_RIGHT (uic)) ||
2414 getSize (operandType (IC_RESULT (uic))) > 1))
2417 /* make sure that the result of this icode is not on the
2418 stack, since acc is used to compute stack offset */
2420 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2421 OP_SYMBOL (IC_RESULT (uic))->onStack)
2424 if (isOperandOnStack(IC_RESULT(uic)))
2428 /* if the usage has only one operand then we can */
2429 if (IC_LEFT (uic) == NULL ||
2430 IC_RIGHT (uic) == NULL)
2433 /* if the other operand uses the accumulator then we cannot */
2434 if ( (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
2435 operandUsesAcc(IC_RIGHT(uic))) ||
2436 (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
2437 operandUsesAcc(IC_LEFT(uic))) )
2440 /* make sure this is on the left side if not commutative */
2441 /* except for '-', which has been written to be able to
2442 handle reversed operands */
2443 if (!(isCommutativeOp(ic->op) || ic->op == '-') &&
2444 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2448 // this is too dangerous and need further restrictions
2451 /* if one of them is a literal then we can */
2452 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2453 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2455 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2461 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2465 /*-----------------------------------------------------------------*/
2466 /* packForPush - hueristics to reduce iCode for pushing */
2467 /*-----------------------------------------------------------------*/
2469 packForPush (iCode * ic, eBBlock ** ebpp, int blockno)
2473 struct eBBlock * ebp=ebpp[blockno];
2475 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2478 /* must have only definition & one usage */
2479 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2480 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2483 /* find the definition */
2484 if (!(dic = hTabItemWithKey (iCodehTab,
2485 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2488 if (dic->op != '=' || POINTER_SET (dic))
2491 if (dic->seq < ebp->fSeq) { // Evelyn did this
2493 for (i=0; i<blockno; i++) {
2494 if (dic->seq >= ebpp[i]->fSeq && dic->seq <= ebpp[i]->lSeq) {
2499 wassert (i!=blockno); // no way to recover from here
2502 if (IS_SYMOP(IC_RIGHT(dic))) {
2503 /* make sure the right side does not have any definitions
2505 dbv = OP_DEFS(IC_RIGHT(dic));
2506 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2507 if (bitVectBitValue(dbv,lic->key))
2510 /* make sure they have the same type */
2511 if (IS_SPEC(operandType(IC_LEFT(ic))))
2513 sym_link *itype=operandType(IC_LEFT(ic));
2514 sym_link *ditype=operandType(IC_RIGHT(dic));
2516 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2517 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2520 /* extend the live range of replaced operand if needed */
2521 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2522 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
2524 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2527 /* we now we know that it has one & only one def & use
2528 and the that the definition is an assignment */
2529 ReplaceOpWithCheaperOp(&IC_LEFT (ic), IC_RIGHT (dic));
2530 remiCodeFromeBBlock (ebp, dic);
2531 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2534 /*-----------------------------------------------------------------*/
2535 /* packRegisters - does some transformations to reduce register */
2537 /*-----------------------------------------------------------------*/
2539 packRegisters (eBBlock ** ebpp, int blockno)
2543 eBBlock *ebp=ebpp[blockno];
2550 /* look for assignments of the form */
2551 /* iTempNN = TRueSym (someoperation) SomeOperand */
2553 /* TrueSym := iTempNN:1 */
2554 for (ic = ebp->sch; ic; ic = ic->next)
2556 /* find assignment of the form TrueSym := iTempNN:1 */
2557 if (ic->op == '=' && !POINTER_SET (ic))
2558 change += packRegsForAssign (ic, ebp);
2565 for (ic = ebp->sch; ic; ic = ic->next)
2567 /* if this is an itemp & result of an address of a true sym
2568 then mark this as rematerialisable */
2569 if (ic->op == ADDRESS_OF &&
2570 IS_ITEMP (IC_RESULT (ic)) &&
2571 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2572 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2573 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2576 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2577 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2578 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2582 /* if straight assignment then carry remat flag if
2583 this is the only definition */
2584 if (ic->op == '=' &&
2585 !POINTER_SET (ic) &&
2586 IS_SYMOP (IC_RIGHT (ic)) &&
2587 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2588 !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode) &&
2589 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2592 OP_SYMBOL (IC_RESULT (ic))->remat =
2593 OP_SYMBOL (IC_RIGHT (ic))->remat;
2594 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2595 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2598 /* if cast to a generic pointer & the pointer being
2599 cast is remat, then we can remat this cast as well */
2600 if (ic->op == CAST &&
2601 IS_SYMOP(IC_RIGHT(ic)) &&
2602 OP_SYMBOL(IC_RIGHT(ic))->remat ) {
2603 sym_link *to_type = operandType(IC_LEFT(ic));
2604 sym_link *from_type = operandType(IC_RIGHT(ic));
2605 if (IS_GENPTR(to_type) && IS_PTR(from_type)) {
2606 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2607 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2608 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2612 /* if this is a +/- operation with a rematerizable
2613 then mark this as rematerializable as well */
2614 if ((ic->op == '+' || ic->op == '-') &&
2615 (IS_SYMOP (IC_LEFT (ic)) &&
2616 IS_ITEMP (IC_RESULT (ic)) &&
2617 IS_OP_LITERAL (IC_RIGHT (ic))) &&
2618 OP_SYMBOL (IC_LEFT (ic))->remat &&
2619 (!IS_SYMOP (IC_RIGHT (ic)) || !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode)) &&
2620 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1)
2622 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2623 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2624 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2627 /* mark the pointer usages */
2628 if (POINTER_SET (ic))
2629 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2631 if (POINTER_GET (ic) &&
2632 IS_SYMOP(IC_LEFT (ic)))
2633 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2637 /* if we are using a symbol on the stack
2638 then we should say mcs51_ptrRegReq */
2639 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2640 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2641 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2642 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2643 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2644 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2647 if (IS_SYMOP (IC_LEFT (ic)))
2648 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2649 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2650 if (IS_SYMOP (IC_RIGHT (ic)))
2651 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2652 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2653 if (IS_SYMOP (IC_RESULT (ic)))
2654 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2655 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2659 /* if the condition of an if instruction
2660 is defined in the previous instruction and
2661 this is the only usage then
2662 mark the itemp as a conditional */
2663 if ((IS_CONDITIONAL (ic) ||
2664 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2665 ic->next && ic->next->op == IFX &&
2666 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2667 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2668 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2670 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2674 /* reduce for support function calls */
2675 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2676 packRegsForSupport (ic, ebp);
2678 /* some cases the redundant moves can
2679 can be eliminated for return statements */
2680 if ((ic->op == RETURN || (ic->op == SEND && ic->argreg == 1)) &&
2681 !isOperandInFarSpace (IC_LEFT (ic)) &&
2682 options.model == MODEL_SMALL) {
2683 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2686 /* if pointer set & left has a size more than
2687 one and right is not in far space */
2688 if (POINTER_SET (ic) &&
2689 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2690 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2691 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2692 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2693 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2695 /* if pointer get */
2696 if (POINTER_GET (ic) &&
2697 IS_SYMOP (IC_LEFT (ic)) &&
2698 !isOperandInFarSpace (IC_RESULT (ic)) &&
2699 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2700 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2701 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2702 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2705 /* if this is cast for intergral promotion then
2706 check if only use of the definition of the
2707 operand being casted/ if yes then replace
2708 the result of that arithmetic operation with
2709 this result and get rid of the cast */
2712 sym_link *fromType = operandType (IC_RIGHT (ic));
2713 sym_link *toType = operandType (IC_LEFT (ic));
2715 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2716 getSize (fromType) != getSize (toType) &&
2717 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2720 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2723 if (IS_ARITHMETIC_OP (dic))
2725 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2726 ReplaceOpWithCheaperOp(&IC_RESULT (dic), IC_RESULT (ic));
2727 remiCodeFromeBBlock (ebp, ic);
2728 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
2729 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2730 OP_DEFS(IC_RESULT (dic))=bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2734 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2740 /* if the type from and type to are the same
2741 then if this is the only use then packit */
2742 if (compareType (operandType (IC_RIGHT (ic)),
2743 operandType (IC_LEFT (ic))) == 1)
2745 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2748 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2749 ReplaceOpWithCheaperOp(&IC_RESULT (dic), IC_RESULT (ic));
2750 remiCodeFromeBBlock (ebp, ic);
2751 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
2752 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2753 OP_DEFS(IC_RESULT (dic))=bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2761 iTempNN := (some variable in farspace) V1
2766 if (ic->op == IPUSH)
2768 packForPush (ic, ebpp, blockno);
2772 /* pack registers for accumulator use, when the
2773 result of an arithmetic or bit wise operation
2774 has only one use, that use is immediately following
2775 the defintion and the using iCode has only one
2776 operand or has two operands but one is literal &
2777 the result of that operation is not on stack then
2778 we can leave the result of this operation in acc:b
2780 if ((IS_ARITHMETIC_OP (ic)
2781 || IS_CONDITIONAL(ic)
2782 || IS_BITWISE_OP (ic)
2783 || ic->op == LEFT_OP || ic->op == RIGHT_OP || ic->op == CALL
2784 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2786 IS_ITEMP (IC_RESULT (ic)) &&
2787 getSize (operandType (IC_RESULT (ic))) <= 2)
2789 packRegsForAccUse (ic);
2793 /*-----------------------------------------------------------------*/
2794 /* assignRegisters - assigns registers to each live range as need */
2795 /*-----------------------------------------------------------------*/
2797 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2802 setToNull ((void *) &_G.funcrUsed);
2803 setToNull ((void *) &_G.regAssigned);
2804 setToNull ((void *) &_G.totRegAssigned);
2805 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2808 /* change assignments this will remove some
2809 live ranges reducing some register pressure */
2810 for (i = 0; i < count; i++)
2811 packRegisters (ebbs, i);
2813 if (options.dump_pack)
2814 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2816 /* first determine for each live range the number of
2817 registers & the type of registers required for each */
2820 /* and serially allocate registers */
2821 serialRegAssign (ebbs, count);
2824 setToNull ((void *) &_G.regAssigned);
2825 setToNull ((void *) &_G.totRegAssigned);
2828 /* if stack was extended then tell the user */
2831 /* werror(W_TOOMANY_SPILS,"stack", */
2832 /* _G.stackExtend,currFunc->name,""); */
2838 /* werror(W_TOOMANY_SPILS,"data space", */
2839 /* _G.dataExtend,currFunc->name,""); */
2843 /* after that create the register mask
2844 for each of the instruction */
2845 createRegMask (ebbs, count);
2847 /* redo that offsets for stacked automatic variables */
2848 redoStackOffsets ();
2850 if (options.dump_rassgn)
2852 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2853 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2856 /* do the overlaysegment stuff SDCCmem.c */
2857 doOverlays (ebbs, count);
2859 /* now get back the chain */
2860 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2864 /* free up any _G.stackSpil locations allocated */
2865 applyToSet (_G.stackSpil, deallocStackSpil);
2867 setToNull ((void **) &_G.stackSpil);
2868 setToNull ((void **) &_G.spiltSet);
2869 /* mark all registers as free */