1 /*-------------------------------------------------------------------------
2 SDCCcse.c - source file for Common Subexpressions and other utility
4 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1998)
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding!
23 -------------------------------------------------------------------------*/
28 /*-----------------------------------------------------------------*/
29 /* newCseDef - new cseDef */
30 /*-----------------------------------------------------------------*/
32 newCseDef (operand * sym, iCode * ic)
37 cdp = Safe_calloc (1, sizeof (cseDef));
48 /*-----------------------------------------------------------------*/
49 /* int isCseDefEqual - two definitions are equal */
50 /*-----------------------------------------------------------------*/
52 isCseDefEqual (void *vsrc, void *vdest)
60 return (src->key == dest->key &&
61 src->diCode == dest->diCode);
65 /*-----------------------------------------------------------------*/
66 /* pcseDef - in the cseDef */
67 /*-----------------------------------------------------------------*/
69 pcseDef (void *item, va_list ap)
77 fprintf (stdout, "**null op**");
78 printOperand (cdp->sym, stdout);
79 icTab = getTableEntry (cdp->diCode->op);
80 icTab->iCodePrint (stdout, cdp->diCode, icTab->printName);
84 /*-----------------------------------------------------------------*/
85 /* replaceAllSymBySym - replaces all operands by operand in an */
86 /* instruction chain */
87 /*-----------------------------------------------------------------*/
89 replaceAllSymBySym (iCode * ic, operand * from, operand * to, bitVect ** ndpset)
93 for (lic = ic; lic; lic = lic->next)
97 /* do the special cases first */
101 IC_COND (lic)->key == from->key)
104 bitVectUnSetBit (OP_USES (from), lic->key);
105 OP_USES (to) = bitVectSetBit (OP_USES (to), lic->key);
106 siaddr = IC_COND (lic)->isaddr;
107 IC_COND (lic) = operandFromOperand (to);
108 IC_COND (lic)->isaddr = siaddr;
114 if (lic->op == JUMPTABLE)
117 IC_JTCOND (lic)->key == from->key)
120 bitVectUnSetBit (OP_USES (from), lic->key);
121 OP_USES (to) = bitVectSetBit (OP_USES (to), lic->key);
122 siaddr = IC_COND (lic)->isaddr;
123 IC_JTCOND (lic) = operandFromOperand (to);
124 IC_JTCOND (lic)->isaddr = siaddr;
130 if (IC_RESULT (lic) && IC_RESULT (lic)->key == from->key)
132 /* maintain du chains */
133 if (POINTER_SET (lic))
135 bitVectUnSetBit (OP_USES (from), lic->key);
136 OP_USES (to) = bitVectSetBit (OP_USES (to), lic->key);
138 /* also check if the "from" was in the non-dominating
139 pointer sets and replace it with "to" in the bitVector */
140 if (bitVectBitValue (*ndpset, from->key))
142 bitVectUnSetBit (*ndpset, from->key);
143 bitVectSetBit (*ndpset, to->key);
149 bitVectUnSetBit (OP_DEFS (from), lic->key);
150 OP_DEFS (to) = bitVectSetBit (OP_DEFS (to), lic->key);
152 siaddr = IC_RESULT (lic)->isaddr;
153 IC_RESULT (lic) = operandFromOperand (to);
154 IC_RESULT (lic)->isaddr = siaddr;
158 IC_RIGHT (lic) && IC_RIGHT (lic)->key == from->key)
160 bitVectUnSetBit (OP_USES (from), lic->key);
161 OP_USES (to) = bitVectSetBit (OP_USES (to), lic->key);
162 siaddr = IC_RIGHT (lic)->isaddr;
163 IC_RIGHT (lic) = operandFromOperand (to);
164 IC_RIGHT (lic)->isaddr = siaddr;
168 IC_LEFT (lic) && IC_LEFT (lic)->key == from->key)
170 bitVectUnSetBit (OP_USES (from), lic->key);
171 OP_USES (to) = bitVectSetBit (OP_USES (to), lic->key);
172 siaddr = IC_LEFT (lic)->isaddr;
173 IC_LEFT (lic) = operandFromOperand (to);
174 IC_LEFT (lic)->isaddr = siaddr;
179 /*-----------------------------------------------------------------*/
180 /* iCodeKeyIs - if the icode keys match then return 1 */
181 /*-----------------------------------------------------------------*/
182 DEFSETFUNC (iCodeKeyIs)
187 if (cdp->diCode->key == key)
193 /*-----------------------------------------------------------------*/
194 /* removeFromInExprs - removes an icode from inexpressions */
195 /*-----------------------------------------------------------------*/
196 DEFSETFUNC (removeFromInExprs)
200 V_ARG (operand *, from);
201 V_ARG (operand *, to);
202 V_ARG (eBBlock *, cbp);
208 deleteItemIf (&ebp->inExprs, iCodeKeyIs, ic->key);
209 if (ebp != cbp && !bitVectBitValue (cbp->domVect, ebp->bbnum))
210 replaceAllSymBySym (ebp->sch, from, to, &ebp->ndompset);
212 applyToSet (ebp->succList, removeFromInExprs, ic, from, to, cbp);
216 /*-----------------------------------------------------------------*/
217 /* isGlobalInNearSpace - return TRUE if valriable is a globalin data */
218 /*-----------------------------------------------------------------*/
220 isGlobalInNearSpace (operand * op)
222 sym_link *type = getSpec (operandType (op));
223 /* this is 8051 specific: optimization
224 suggested by Jean-Louis VERN, with 8051s we have no
225 advantage of putting variables in near space into
227 if (isOperandGlobal (op) && !IN_FARSPACE (SPEC_OCLS (type)) &&
228 IN_DIRSPACE (SPEC_OCLS (type)))
234 /*-----------------------------------------------------------------*/
235 /* findCheaperOp - cseBBlock support routine, will check to see if */
236 /* we have a operand previously defined */
237 /*-----------------------------------------------------------------*/
238 DEFSETFUNC (findCheaperOp)
241 V_ARG (operand *, cop);
242 V_ARG (operand **, opp);
244 /* if we have already found it */
248 /* not found it yet check if this is the one */
249 /* and this is not the defining one */
250 if (cop->key == cdp->key)
253 /* do a special check this will help in */
254 /* constant propagation & dead code elim */
255 /* for assignments only */
256 if (cdp->diCode->op == '=') {
257 /* if the result is volatile then return result */
258 if (IS_OP_VOLATILE (IC_RESULT (cdp->diCode)))
259 *opp = IC_RESULT (cdp->diCode);
261 /* if this is a straight assignment and
262 left is a temp then prefer the temporary to the
264 if (!POINTER_SET (cdp->diCode) &&
265 IS_ITEMP (IC_RESULT (cdp->diCode)) &&
266 IS_TRUE_SYMOP (IC_RIGHT (cdp->diCode)))
267 *opp = IC_RESULT (cdp->diCode);
269 /* if straight assignement && and both
270 are temps then prefer the one that
271 will not need extra space to spil, also
272 take into consideration if right side
273 an induction variable
275 if (!POINTER_SET (cdp->diCode) &&
276 IS_ITEMP (IC_RESULT (cdp->diCode)) &&
277 IS_ITEMP (IC_RIGHT (cdp->diCode)) &&
278 !OP_SYMBOL (IC_RIGHT (cdp->diCode))->isind &&
279 ((!SPIL_LOC (IC_RIGHT (cdp->diCode)) &&
280 SPIL_LOC (IC_RESULT (cdp->diCode))) ||
281 (SPIL_LOC (IC_RESULT (cdp->diCode)) &&
282 SPIL_LOC (IC_RESULT (cdp->diCode)) ==
283 SPIL_LOC (IC_RIGHT (cdp->diCode)))))
284 *opp = IC_RESULT (cdp->diCode);
286 *opp = IC_RIGHT (cdp->diCode);
290 *opp = IC_RESULT (cdp->diCode);
293 /* if this is an assign to a temp. then check
294 if the right side is this then return this */
295 if (IS_TRUE_SYMOP (cop) &&
296 cdp->diCode->op == '=' &&
297 !POINTER_SET (cdp->diCode) &&
298 cop->key == IC_RIGHT (cdp->diCode)->key &&
299 !isGlobalInNearSpace (IC_RIGHT (cdp->diCode)) &&
300 IS_ITEMP (IC_RESULT (cdp->diCode)))
301 *opp = IC_RESULT (cdp->diCode);
304 (SPEC_USIGN(operandType (cop))==SPEC_USIGN(operandType (*opp))) &&
305 (SPEC_LONG(operandType (cop))==SPEC_LONG(operandType (*opp))))
308 if ((isGlobalInNearSpace (cop) &&
309 !isOperandLiteral (*opp)) ||
310 isOperandVolatile (*opp, FALSE)
317 if (cop->key == (*opp)->key)
323 if ((*opp)->isaddr != cop->isaddr && IS_ITEMP (cop))
325 *opp = operandFromOperand (*opp);
326 (*opp)->isaddr = cop->isaddr;
336 /*-----------------------------------------------------------------*/
337 /* findPointerSet - finds the right side of a pointer set op */
338 /*-----------------------------------------------------------------*/
339 DEFSETFUNC (findPointerSet)
342 V_ARG (operand *, op);
343 V_ARG (operand **, opp);
344 V_ARG (operand *, rop);
346 if (POINTER_SET (cdp->diCode) &&
347 IC_RESULT (cdp->diCode)->key == op->key &&
348 !isOperandVolatile (IC_RESULT (cdp->diCode), TRUE) &&
349 !isOperandVolatile (IC_RIGHT (cdp->diCode), TRUE) &&
350 getSize (operandType (IC_RIGHT (cdp->diCode))) ==
351 getSize (operandType (rop)))
353 *opp = IC_RIGHT (cdp->diCode);
360 /*-----------------------------------------------------------------*/
361 /* findPrevIc - cseBBlock support function will return the iCode */
362 /* which matches the current one */
363 /*-----------------------------------------------------------------*/
364 DEFSETFUNC (findPrevIc)
368 V_ARG (iCode **, icp);
370 /* if already found */
374 /* if the iCodes are the same */
375 if (isiCodeEqual (ic, cdp->diCode) &&
376 isOperandEqual (cdp->sym, IC_RESULT (cdp->diCode)))
382 /* if iCodes are not the same */
383 /* see the operands maybe interchanged */
384 if (ic->op == cdp->diCode->op &&
385 (ic->op == '+' || ic->op == '*') &&
386 isOperandEqual (IC_LEFT (ic), IC_RIGHT (cdp->diCode)) &&
387 isOperandEqual (IC_RIGHT (ic), IC_LEFT (cdp->diCode)))
396 /*-----------------------------------------------------------------*/
397 /* ifDefGlobal - if definition is global */
398 /*-----------------------------------------------------------------*/
399 DEFSETFUNC (ifDefGlobal)
403 return (isOperandGlobal (cdp->sym));
406 /*-----------------------------------------------------------------*/
407 /* ifAnyGetPointer - if get pointer icode */
408 /*-----------------------------------------------------------------*/
409 DEFSETFUNC (ifAnyGetPointer)
413 if (cdp->diCode && POINTER_GET (cdp->diCode))
418 /*-----------------------------------------------------------------*/
419 /* ifOperandsHave - if any of the operand are the same as this */
420 /*-----------------------------------------------------------------*/
421 DEFSETFUNC (ifOperandsHave)
424 V_ARG (operand *, op);
427 if (IC_LEFT (cdp->diCode) &&
428 IS_SYMOP (IC_LEFT (cdp->diCode)) &&
429 IC_LEFT (cdp->diCode)->key == op->key)
432 if (IC_RIGHT (cdp->diCode) &&
433 IS_SYMOP (IC_RIGHT (cdp->diCode)) &&
434 IC_RIGHT (cdp->diCode)->key == op->key)
437 /* or if any of the operands are volatile */
438 if (IC_LEFT (cdp->diCode) &&
439 IS_OP_VOLATILE (IC_LEFT (cdp->diCode)))
442 if (IC_RIGHT (cdp->diCode) &&
443 IS_OP_VOLATILE (IC_RIGHT (cdp->diCode)))
447 if (IC_RESULT (cdp->diCode) &&
448 IS_OP_VOLATILE (IC_RESULT (cdp->diCode)))
454 /*-----------------------------------------------------------------*/
455 /* ifDefSymIs - if a definition is found in the set */
456 /*-----------------------------------------------------------------*/
458 ifDefSymIs (set * cseSet, operand * sym)
463 if (!sym || !IS_SYMOP (sym))
465 for (sl = cseSet; sl; sl = sl->next)
468 if (loop->sym->key == sym->key)
475 /*-----------------------------------------------------------------*/
476 /* ifDefSymIsX - will return 1 if the symbols match */
477 /*-----------------------------------------------------------------*/
478 DEFSETFUNC (ifDefSymIsX)
481 V_ARG (operand *, op);
484 return cdp->sym->key == op->key;
486 return (isOperandEqual (cdp->sym, op));
491 /*-----------------------------------------------------------------*/
492 /* ifDiCodeIs - returns truw if diCode is same */
493 /*-----------------------------------------------------------------*/
495 ifDiCodeIs (set * cseSet, iCode * ic)
503 for (sl = cseSet; sl; sl = sl->next)
506 if (loop->diCode == ic)
513 /*-----------------------------------------------------------------*/
514 /* ifPointerGet - returns true if the icode is pointer get sym */
515 /*-----------------------------------------------------------------*/
516 DEFSETFUNC (ifPointerGet)
519 V_ARG (operand *, op);
520 iCode *dic = cdp->diCode;
521 operand *left = IC_LEFT (cdp->diCode);
523 if (POINTER_GET (dic) && left->key == op->key)
529 /*-----------------------------------------------------------------*/
530 /* ifPointerSet - returns true if the icode is pointer set sym */
531 /*-----------------------------------------------------------------*/
532 DEFSETFUNC (ifPointerSet)
535 V_ARG (operand *, op);
537 if (POINTER_SET (cdp->diCode) &&
538 IC_RESULT (cdp->diCode)->key == op->key)
544 /*-----------------------------------------------------------------*/
545 /* ifDiCodeIsX - will return 1 if the symbols match */
546 /*-----------------------------------------------------------------*/
547 DEFSETFUNC (ifDiCodeIsX)
552 return cdp->diCode == ic;
556 /*-----------------------------------------------------------------*/
557 /* algebraicOpts - does some algebraic optimizations */
558 /*-----------------------------------------------------------------*/
560 algebraicOpts (iCode * ic)
562 /* we don't deal with the following iCodes
573 /* if both operands present & ! IFX */
574 /* then if they are both literal we */
575 /* perform the operation right now */
576 if (IC_RESULT (ic) &&
579 IS_OP_LITERAL (IC_LEFT (ic)) &&
580 IS_OP_LITERAL (IC_RIGHT (ic)))
583 IC_RIGHT (ic) = operandOperation (IC_LEFT (ic),
586 operandType (IC_RESULT (ic)));
589 SET_RESULT_RIGHT (ic);
593 /* if not ifx & only one operand present */
594 if (IC_RESULT (ic) &&
596 IS_OP_LITERAL (IC_LEFT (ic)) &&
600 IC_RIGHT (ic) = operandOperation (IC_LEFT (ic),
603 operandType (IC_RESULT (ic)));
606 SET_RESULT_RIGHT (ic);
611 /* a special case : or in short a kludgy solution will think
612 about a better solution over a glass of wine someday */
613 if (ic->op == GET_VALUE_AT_ADDRESS)
616 if (IS_ITEMP (IC_RESULT (ic)) &&
617 IS_TRUE_SYMOP (IC_LEFT (ic)))
621 IC_RIGHT (ic) = operandFromOperand (IC_LEFT (ic));
622 IC_RIGHT (ic)->isaddr = 0;
624 IC_RESULT (ic) = operandFromOperand (IC_RESULT (ic));
625 IC_RESULT (ic)->isaddr = 0;
626 setOperandType (IC_RESULT (ic), operandType (IC_RIGHT (ic)));
630 if (IS_ITEMP (IC_LEFT (ic)) &&
631 IS_ITEMP (IC_RESULT (ic)) &&
632 /* !OP_SYMBOL(IC_RESULT(ic))->isreqv && */
633 /* !OP_SYMBOL(IC_LEFT(ic))->isreqv && */
634 !IC_LEFT (ic)->isaddr)
637 IC_RIGHT (ic) = operandFromOperand (IC_LEFT (ic));
638 IC_RIGHT (ic)->isaddr = 0;
639 IC_RESULT (ic) = operandFromOperand (IC_RESULT (ic));
640 IC_RESULT (ic)->isaddr = 0;
648 /* depending on the operation */
652 /* if adding the same thing change to left shift by 1 */
653 if (IC_LEFT (ic)->key == IC_RIGHT (ic)->key &&
654 !IS_FLOAT (operandType (IC_RESULT (ic))))
657 IC_RIGHT (ic) = operandFromLit (1);
660 /* if addition then check if one of them is a zero */
661 /* if yes turn it into assignmnt */
662 if (IS_OP_LITERAL (IC_LEFT (ic)) &&
663 operandLitValue (IC_LEFT (ic)) == 0.0)
668 SET_ISADDR (IC_RESULT (ic), 0);
669 SET_ISADDR (IC_RIGHT (ic), 0);
672 if (IS_OP_LITERAL (IC_RIGHT (ic)) &&
673 operandLitValue (IC_RIGHT (ic)) == 0.0)
677 IC_RIGHT (ic) = IC_LEFT (ic);
679 SET_ISADDR (IC_RIGHT (ic), 0);
680 SET_ISADDR (IC_RESULT (ic), 0);
685 /* if subtracting the the same thing then zero */
686 if (IC_LEFT (ic)->key == IC_RIGHT (ic)->key)
689 IC_RIGHT (ic) = operandFromLit (0);
691 IC_RESULT (ic) = operandFromOperand (IC_RESULT (ic));
692 IC_RESULT (ic)->isaddr = 0;
696 /* if subtraction then check if one of the operand */
697 /* is zero then depending on which operand change */
698 /* to assignment or unary minus */
699 if (IS_OP_LITERAL (IC_RIGHT (ic)) &&
700 operandLitValue (IC_RIGHT (ic)) == 0.0)
702 /* right size zero change to assignment */
704 IC_RIGHT (ic) = IC_LEFT (ic);
706 SET_ISADDR (IC_RIGHT (ic), 0);
707 SET_ISADDR (IC_RESULT (ic), 0);
710 if (IS_OP_LITERAL (IC_LEFT (ic)) &&
711 operandLitValue (IC_LEFT (ic)) == 0.0)
713 /* left zero turn into an unary minus */
715 IC_LEFT (ic) = IC_RIGHT (ic);
716 IC_RIGHT (ic) = NULL;
720 /* if multiplication then check if either of */
721 /* them is zero then the result is zero */
722 /* if either of them is one then result is */
725 if (IS_OP_LITERAL (IC_LEFT (ic)))
728 if (operandLitValue (IC_LEFT (ic)) == 0.0)
731 IC_RIGHT (ic) = IC_LEFT (ic);
733 SET_RESULT_RIGHT (ic);
736 if (operandLitValue (IC_LEFT (ic)) == 1.0)
740 SET_RESULT_RIGHT (ic);
745 if (IS_OP_LITERAL (IC_RIGHT (ic)))
748 if (operandLitValue (IC_RIGHT (ic)) == 0.0)
752 SET_RESULT_RIGHT (ic);
756 if (operandLitValue (IC_RIGHT (ic)) == 1.0)
759 IC_RIGHT (ic) = IC_LEFT (ic);
761 SET_RESULT_RIGHT (ic);
767 /* if division by self then 1 */
768 if (IC_LEFT (ic)->key == IC_RIGHT (ic)->key)
771 IC_RIGHT (ic) = operandFromLit (1);
773 IC_RESULT (ic) = operandFromOperand (IC_RESULT (ic));
774 IC_RESULT (ic)->isaddr = 0;
776 /* if this is a division then check if right */
777 /* is one then change it to an assignment */
778 if (IS_OP_LITERAL (IC_RIGHT (ic)) &&
779 operandLitValue (IC_RIGHT (ic)) == 1.0)
783 IC_RIGHT (ic) = IC_LEFT (ic);
785 SET_RESULT_RIGHT (ic);
789 /* if both are the same for an comparison operators */
793 if (isOperandEqual (IC_LEFT (ic), IC_RIGHT (ic)))
796 IC_RIGHT (ic) = operandFromLit (1);
798 SET_RESULT_RIGHT (ic);
804 if (isOperandEqual (IC_LEFT (ic), IC_RIGHT (ic)))
807 IC_RIGHT (ic) = operandFromLit (0);
809 SET_RESULT_RIGHT (ic);
813 /* if this is a cast of a literal value */
814 if (IS_OP_LITERAL (IC_RIGHT (ic)))
818 operandFromValue (valCastLiteral (operandType (IC_LEFT (ic)),
819 operandLitValue (IC_RIGHT (ic))));
821 SET_ISADDR (IC_RESULT (ic), 0);
823 /* if casting to the same */
824 if (compareType (operandType (IC_RESULT (ic)),
825 operandType (IC_RIGHT (ic))) == 1)
829 SET_ISADDR (IC_RESULT (ic), 0);
833 if (IS_OP_LITERAL (IC_LEFT (ic)))
837 (operandLitValue (IC_LEFT (ic)) == 0 ?
838 operandFromLit (1) : operandFromLit (0));
840 SET_ISADDR (IC_RESULT (ic), 0);
846 #define OTHERS_PARM(s) (s->_isparm && !s->ismyparm)
847 /*-----------------------------------------------------------------*/
848 /* updateSpillLocation - keeps track of register spill location */
849 /*-----------------------------------------------------------------*/
851 updateSpillLocation (iCode * ic)
856 if (POINTER_SET (ic))
862 /* for the form true_symbol := iTempNN */
863 if (ASSIGN_ITEMP_TO_SYM (ic)
864 && !SPIL_LOC (IC_RIGHT (ic)))
867 setype = getSpec (operandType (IC_RESULT (ic)));
869 if (!IC_RIGHT (ic)->noSpilLoc &&
870 !IS_VOLATILE (setype) &&
871 !IN_FARSPACE (SPEC_OCLS (setype)) &&
872 !OTHERS_PARM (OP_SYMBOL (IC_RESULT (ic))))
874 SPIL_LOC (IC_RIGHT (ic)) =
875 IC_RESULT (ic)->operand.symOperand;
878 if (ASSIGN_ITEMP_TO_ITEMP (ic) &&
879 !SPIL_LOC (IC_RIGHT (ic)) &&
880 !bitVectBitsInCommon (OP_DEFS (IC_RIGHT (ic)), OP_USES (IC_RESULT (ic))) &&
881 OP_SYMBOL (IC_RESULT (ic))->isreqv)
884 setype = getSpec (operandType (IC_RESULT (ic)));
886 if (!IC_RIGHT (ic)->noSpilLoc &&
887 !IS_VOLATILE (setype) &&
888 !IN_FARSPACE (SPEC_OCLS (setype)) &&
889 !OTHERS_PARM (OP_SYMBOL (IC_RESULT (ic))))
891 SPIL_LOC (IC_RIGHT (ic)) =
892 SPIL_LOC (IC_RESULT (ic));
896 /*-----------------------------------------------------------------*/
897 /* setUsesDef - sets the uses def bitvector for a given operand */
898 /*-----------------------------------------------------------------*/
900 setUsesDefs (operand * op, bitVect * bdefs,
901 bitVect * idefs, bitVect ** oud)
903 /* compute the definitions alive at this point */
904 bitVect *adefs = bitVectUnion (bdefs, idefs);
906 /* of these definitions find the ones that are */
907 /* for this operand */
908 adefs = bitVectIntersect (adefs, OP_DEFS (op));
910 /* these are the definitions that this operand can use */
911 op->usesDefs = adefs;
913 /* the out defs is an union */
914 *oud = bitVectUnion (*oud, adefs);
917 /*-----------------------------------------------------------------*/
918 /* unsetDefsAndUses - clear this operation for the operands */
919 /*-----------------------------------------------------------------*/
921 unsetDefsAndUses (iCode * ic)
923 if (ic->op == JUMPTABLE)
926 /* take away this definition from the def chain of the */
927 /* result & take away from use set of the operands */
930 /* turn off def set */
931 if (IS_SYMOP (IC_RESULT (ic)))
933 if (!POINTER_SET (ic))
934 bitVectUnSetBit (OP_DEFS (IC_RESULT (ic)), ic->key);
936 bitVectUnSetBit (OP_USES (IC_RESULT (ic)), ic->key);
938 /* turn off the useSet for the operands */
939 if (IS_SYMOP (IC_LEFT (ic)))
940 bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
942 if (IS_SYMOP (IC_RIGHT (ic)))
943 bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
946 /* must be ifx turn off the use */ if (IS_SYMOP (IC_COND (ic)))
947 bitVectUnSetBit (OP_USES (IC_COND (ic)), ic->key);
950 /*-----------------------------------------------------------------*/
951 /* ifxOptimize - changes ifx conditions if it can */
952 /*-----------------------------------------------------------------*/
954 ifxOptimize (iCode * ic, set * cseSet,
956 eBBlock * ebb, int *change,
957 eBBlock ** ebbs, int count)
962 /* if the condition can be replaced */
966 applyToSetFTrue (cseSet, findCheaperOp, IC_COND (ic), &pdop);
974 /* if the conditional is a literal then */
975 if (IS_OP_LITERAL (IC_COND (ic)))
978 if ((operandLitValue (IC_COND (ic)) != 0.0) && IC_TRUE (ic))
981 /* change to a goto */
983 IC_LABEL (ic) = IC_TRUE (ic);
990 if (!operandLitValue (IC_COND (ic)) && IC_FALSE (ic))
993 IC_LABEL (ic) = IC_FALSE (ic);
999 /* then kill this if condition */
1000 remiCodeFromeBBlock (ebb, ic);
1004 /* now we need to recompute the control flow */
1005 /* since the control flow has changed */
1006 /* this is very expensive but it does not happen */
1007 /* too often, if it does happen then the user pays */
1009 computeControlFlow (ebbs, count, 1);
1010 werror (W_CONTROL_FLOW, ic->filename, ic->lineno);
1014 /* if there is only one successor and that successor
1015 is the same one we are conditionally going to then
1016 we can remove this conditional statement */
1017 label = (IC_TRUE (ic) ? IC_TRUE (ic) : IC_FALSE (ic));
1018 if (elementsInSet (ebb->succList) == 1 &&
1019 isinSet (ebb->succList, eBBWithEntryLabel (ebbs, label, count)))
1022 remiCodeFromeBBlock (ebb, ic);
1023 computeControlFlow (ebbs, count, 1);
1024 werror (W_CONTROL_FLOW, ic->filename, ic->lineno);
1029 /* if it remains an IFX the update the use Set */
1030 OP_USES (IC_COND (ic)) = bitVectSetBit (OP_USES (IC_COND (ic)), ic->key);
1031 setUsesDefs (IC_COND (ic), ebb->defSet, ebb->outDefs, &ebb->usesDefs);
1035 /*-----------------------------------------------------------------*/
1036 /* diCodeForSym - finds the definiting instruction for a symbol */
1037 /*-----------------------------------------------------------------*/
1038 DEFSETFUNC (diCodeForSym)
1041 V_ARG (operand *, sym);
1042 V_ARG (iCode **, dic);
1044 /* if already found */
1048 /* if not if this is the defining iCode */
1049 if (sym->key == cdp->key)
1058 /*-----------------------------------------------------------------*/
1059 /* constFold - does some constant folding */
1060 /*-----------------------------------------------------------------*/
1062 constFold (iCode * ic, set * cseSet)
1066 /* this routine will change
1072 /* deal with only + & - */
1073 if (ic->op != '+' &&
1077 /* this check is a hueristic to prevent live ranges
1078 from becoming too long */
1079 if (IS_PTR (operandType (IC_RESULT (ic))))
1082 /* check if operation with a literal */
1083 if (!IS_OP_LITERAL (IC_RIGHT (ic)))
1086 /* check if we can find a definition for the
1088 if (!(applyToSet (cseSet, diCodeForSym, IC_LEFT (ic), &dic)))
1091 /* check that this is also a +/- */
1092 if (dic->op != '+' && dic->op != '-')
1095 /* with a literal */
1096 if (!IS_OP_LITERAL (IC_RIGHT (dic)))
1099 /* find the definition of the left operand
1100 of dic.then check if this defined with a
1101 get_pointer return 0 if the pointer size is
1102 less than 2 (MCS51 specific) */
1103 if (!(applyToSet (cseSet, diCodeForSym, IC_LEFT (dic), &ldic)))
1106 if (POINTER_GET (ldic) && getSize (operandType (IC_LEFT (ldic))) <= 1)
1109 /* it is if the operations are the same */
1110 /* the literal parts need to be added */
1111 IC_LEFT (ic) = operandFromOperand (IC_LEFT (dic));
1112 if (ic->op == dic->op)
1113 IC_RIGHT (ic) = operandFromLit (operandLitValue (IC_RIGHT (ic)) +
1114 operandLitValue (IC_RIGHT (dic)));
1116 IC_RIGHT (ic) = operandFromLit (operandLitValue (IC_RIGHT (ic)) -
1117 operandLitValue (IC_RIGHT (dic)));
1119 if (IS_ITEMP (IC_RESULT (ic)))
1121 SPIL_LOC (IC_RESULT (ic)) = NULL;
1122 IC_RESULT (ic)->noSpilLoc = 1;
1129 /*-----------------------------------------------------------------*/
1130 /* deleteGetPointers - called when a pointer is passed as parm */
1131 /* will delete from cseSet all get pointers computed from this */
1132 /* pointer. A simple ifOperandsHave is not good enough here */
1133 /*-----------------------------------------------------------------*/
1135 deleteGetPointers (set ** cseSet, set ** pss, operand * op, eBBlock * ebb)
1137 set *compItems = NULL;
1142 if (!*cseSet && !*pss)
1145 /* first find all items computed from this operand .
1146 This done fairly simply go thru the list and find
1147 those that are computed by arthimetic with this
1149 for (cdp = setFirstItem (*cseSet); cdp; cdp = setNextItem (*cseSet))
1151 if (IS_ARITHMETIC_OP (cdp->diCode))
1153 if (isOperandEqual (IC_LEFT (cdp->diCode), op) ||
1154 isOperandEqual (IC_RIGHT (cdp->diCode), op))
1156 /* save it in our list of items */
1157 addSet (&compItems, IC_RESULT (cdp->diCode));
1159 /* also check for those computed from our computed
1160 list . This will take care of situations like
1161 iTemp1 = iTemp0 + 8;
1162 iTemp2 = iTemp1 + 8; */
1163 if (isinSetWith (compItems, (void*)IC_LEFT (cdp->diCode),
1164 (insetwithFunc)isOperandEqual) ||
1165 isinSetWith (compItems, (void*)IC_RIGHT (cdp->diCode),
1166 (insetwithFunc)isOperandEqual))
1168 addSet (&compItems, IC_RESULT (cdp->diCode));
1173 /* now delete all pointer gets with this op */
1174 deleteItemIf (cseSet, ifPointerGet, op);
1175 deleteItemIf (pss, ifPointerSet, op);
1177 /* set the bit vector used by dataFlow computation later */
1178 ebb->ptrsSet = bitVectSetBit (ebb->ptrsSet, op->key);
1179 /* now for the computed items */
1180 for (cop = setFirstItem (compItems); cop; cop = setNextItem (compItems))
1182 ebb->ptrsSet = bitVectSetBit (ebb->ptrsSet, cop->key);
1183 deleteItemIf (cseSet, ifPointerGet, cop);
1184 deleteItemIf (pss, ifPointerSet, cop);
1188 /*-----------------------------------------------------------------*/
1189 /* delGetPointerSucc - delete get pointer from inExprs of succ with */
1190 /* dfnum > supplied */
1191 /*-----------------------------------------------------------------*/
1192 DEFSETFUNC (delGetPointerSucc)
1194 eBBlock *ebp = item;
1195 V_ARG (operand *, op);
1202 if (ebp->dfnum > dfnum)
1204 deleteItemIf (&ebp->inExprs, ifPointerGet, op);
1207 return applyToSet (ebp->succList, delGetPointerSucc, op, dfnum);
1210 /*-----------------------------------------------------------------*/
1211 /* fixUpTypes - KLUGE HACK fixup a lowering problem */
1212 /*-----------------------------------------------------------------*/
1214 fixUpTypes (iCode * ic)
1216 sym_link *t1 = operandType (IC_LEFT (ic)), *t2;
1218 if (TARGET_IS_DS390)
1224 /* for pointer_gets if the types of result & left r the
1225 same then change it type of result to next */
1227 compareType (t2 = operandType (IC_RESULT (ic)), t1) == 1)
1229 setOperandType (IC_RESULT (ic), t2->next);
1233 /*-----------------------------------------------------------------*/
1234 /* cseBBlock - common subexpression elimination for basic blocks */
1235 /* this is the hackiest kludgiest routine in the whole */
1236 /* system. also the most important, since almost all */
1237 /* data flow related information is computed by it */
1238 /*-----------------------------------------------------------------*/
1240 cseBBlock (eBBlock * ebb, int computeOnly,
1241 eBBlock ** ebbs, int count)
1247 set *ptrSetSet = NULL;
1249 /* if this block is not reachable */
1253 /* set of common subexpressions */
1254 cseSet = setFromSet (ebb->inExprs);
1256 /* these will be computed by this routine */
1257 setToNull ((void **) &ebb->outDefs);
1258 setToNull ((void **) &ebb->defSet);
1259 setToNull ((void **) &ebb->usesDefs);
1260 setToNull ((void **) &ebb->ptrsSet);
1261 setToNull ((void **) &ebb->addrOf);
1262 setToNull ((void **) &ebb->ldefs);
1264 ebb->outDefs = bitVectCopy (ebb->inDefs);
1265 bitVectDefault = iCodeKey;
1266 ebb->defSet = newBitVect (iCodeKey);
1267 ebb->usesDefs = newBitVect (iCodeKey);
1269 /* for all the instructions in this block do */
1270 for (ic = ebb->sch; ic; ic = ic->next)
1280 /* if this is an assignment from true symbol
1281 to a temp then do pointer post inc/dec optimzation */
1282 if (ic->op == '=' && !POINTER_SET (ic) &&
1283 IS_PTR (operandType (IC_RESULT (ic))))
1285 ptrPostIncDecOpt (ic);
1288 /* clear the def & use chains for the operands involved */
1289 /* in this operation . since it can change due to opts */
1290 unsetDefsAndUses (ic);
1292 if (ic->op == PCALL || ic->op == CALL || ic->op == RECEIVE)
1294 /* add to defSet of the symbol */
1295 OP_DEFS (IC_RESULT (ic)) =
1296 bitVectSetBit (OP_DEFS (IC_RESULT (ic)), ic->key);
1297 /* add to the definition set of this block */
1298 ebb->defSet = bitVectSetBit (ebb->defSet, ic->key);
1299 ebb->ldefs = bitVectSetBit (ebb->ldefs, ic->key);
1300 ebb->outDefs = bitVectCplAnd (ebb->outDefs, OP_DEFS (IC_RESULT (ic)));
1301 setUsesDefs (IC_RESULT (ic), ebb->defSet, ebb->outDefs, &ebb->usesDefs);
1302 /* delete global variables from the cseSet
1303 since they can be modified by the function call */
1304 deleteItemIf (&cseSet, ifDefGlobal);
1305 /* delete all getpointer iCodes from cseSet, this should
1306 be done only for global arrays & pointers but at this
1307 point we don't know if globals, so to be safe do all */
1308 deleteItemIf (&cseSet, ifAnyGetPointer);
1311 /* for pcall & ipush we need to add to the useSet */
1312 if ((ic->op == PCALL ||
1316 IS_SYMOP (IC_LEFT (ic)))
1319 /* check if they can be replaced */
1323 applyToSetFTrue (cseSet, findCheaperOp, IC_LEFT (ic), &pdop);
1325 IC_LEFT (ic) = pdop;
1327 /* the lookup could have changed it */
1328 if (IS_SYMOP (IC_LEFT (ic)))
1330 OP_USES (IC_LEFT (ic)) =
1331 bitVectSetBit (OP_USES (IC_LEFT (ic)), ic->key);
1332 setUsesDefs (IC_LEFT (ic), ebb->defSet,
1333 ebb->outDefs, &ebb->usesDefs);
1337 /* if we a sending a pointer as a parameter
1338 then kill all cse since the pointed to item
1339 might be changed in the function being called */
1340 if ((ic->op == IPUSH || ic->op == SEND) &&
1341 IS_PTR (operandType (IC_LEFT (ic))))
1343 deleteGetPointers (&cseSet, &ptrSetSet, IC_LEFT (ic), ebb);
1344 ebb->ptrsSet = bitVectSetBit (ebb->ptrsSet, IC_LEFT (ic)->key);
1345 for (i = 0; i < count; ebbs[i++]->visited = 0);
1346 applyToSet (ebb->succList, delGetPointerSucc,
1347 IC_LEFT (ic), ebb->dfnum);
1352 /* if jumptable then mark the usage */
1353 if (ic->op == JUMPTABLE)
1355 OP_USES (IC_JTCOND (ic)) =
1356 bitVectSetBit (OP_USES (IC_JTCOND (ic)), ic->key);
1357 setUsesDefs (IC_JTCOND (ic), ebb->defSet,
1358 ebb->outDefs, &ebb->usesDefs);
1365 /* do some algebraic optimizations if possible */
1367 while (constFold (ic, cseSet));
1370 if (POINTER_GET (ic) && !IS_PTR (operandType (IC_LEFT (ic))))
1372 setOperandType (IC_LEFT (ic),
1373 aggrToPtr (operandType (IC_LEFT (ic)), FALSE));
1377 if (POINTER_SET (ic) && !IS_PTR (operandType (IC_RESULT (ic))))
1379 setOperandType (IC_RESULT (ic),
1380 aggrToPtr (operandType (IC_RESULT (ic)), FALSE));
1383 /* if this is a condition statment then */
1384 /* check if the condition can be replaced */
1387 ifxOptimize (ic, cseSet, computeOnly,
1393 /* if the assignment & result is a temp */
1394 /* see if we can replace it */
1398 /* update the spill location for this */
1399 updateSpillLocation (ic);
1401 if (POINTER_SET (ic) &&
1402 !(IS_BITFIELD (OP_SYMBOL (IC_RESULT (ic))->etype)))
1405 applyToSetFTrue (cseSet, findCheaperOp, IC_RESULT (ic), &pdop);
1406 if (pdop && IS_ITEMP (pdop) && !computeOnly)
1407 IC_RESULT (ic) = pdop;
1411 /* do the operand lookup i.e. for both the */
1412 /* right & left operand : check the cseSet */
1413 /* to see if they have been replaced if yes */
1414 /* then replace them with those from cseSet */
1416 /* and left is a symbol */
1417 if (IS_SYMOP (IC_LEFT (ic)) &&
1418 !computeOnly && ic->op != ADDRESS_OF)
1422 applyToSetFTrue (cseSet, findCheaperOp, IC_LEFT (ic), &pdop);
1425 if (POINTER_GET (ic))
1427 if (IS_ITEMP (pdop) || IS_OP_LITERAL (pdop))
1429 IC_LEFT (ic) = pdop;
1432 /* check if there is a pointer set
1433 for the same pointer visible if yes
1434 then change this into an assignment */
1436 if (applyToSetFTrue (cseSet, findPointerSet, IC_LEFT (ic), &pdop, IC_RESULT (ic)) &&
1437 !bitVectBitValue (ebb->ptrsSet, pdop->key))
1440 IC_LEFT (ic) = NULL;
1441 IC_RIGHT (ic) = pdop;
1442 SET_ISADDR (IC_RESULT (ic), 0);
1448 IC_LEFT (ic) = pdop;
1455 if (IS_SYMOP (IC_RIGHT (ic)) && !computeOnly)
1459 applyToSetFTrue (cseSet, findCheaperOp, IC_RIGHT (ic), &pdop);
1463 IC_RIGHT (ic) = pdop;
1468 /* if left or right changed then do algebraic */
1472 while (constFold (ic, cseSet));
1475 /* if after all this it becomes a assignment to self
1476 then delete it and continue */
1477 if (ASSIGNMENT_TO_SELF (ic))
1479 remiCodeFromeBBlock (ebb, ic);
1483 /* now we will check to see if the entire */
1484 /* operation has been performed before */
1485 /* and is available */
1486 /* don't do assignments they will be killed */
1487 /* by dead code elimination if required do */
1488 /* it only if result is a temporary */
1490 if (!(POINTER_GET (ic) &&
1491 (IS_BITFIELD (OP_SYMBOL (IC_RESULT (ic))->etype) ||
1492 isOperandVolatile (IC_LEFT (ic), TRUE) ||
1493 bitVectBitValue (ebb->ndompset, IC_LEFT (ic)->key))) &&
1495 IS_ITEMP (IC_RESULT (ic)) &&
1498 applyToSet (cseSet, findPrevIc, ic, &pdic);
1499 if (pdic && compareType (operandType (IC_RESULT (pdic)),
1500 operandType (IC_RESULT (ic))) != 1)
1504 /* if found then eliminate this and add to */
1505 /* to cseSet an element containing result */
1506 /* of this with previous opcode */
1510 if (IS_ITEMP (IC_RESULT (ic)))
1513 /* replace in the remaining of this block */
1514 replaceAllSymBySym (ic->next, IC_RESULT (ic), IC_RESULT (pdic), &ebb->ndompset);
1515 /* remove this iCode from inexpressions of all
1516 its successors, it cannot be in the in expressions
1517 of any of the predecessors */
1518 for (i = 0; i < count; ebbs[i++]->visited = 0);
1519 applyToSet (ebb->succList, removeFromInExprs, ic, IC_RESULT (ic),
1520 IC_RESULT (pdic), ebb);
1522 /* if this was moved from another block */
1523 /* then replace in those blocks too */
1527 for (owner = setFirstItem (ic->movedFrom); owner;
1528 owner = setNextItem (ic->movedFrom))
1529 replaceAllSymBySym (owner->sch, IC_RESULT (ic), IC_RESULT (pdic), &owner->ndompset);
1531 pdic->movedFrom = unionSets (pdic->movedFrom, ic->movedFrom, THROW_NONE);
1534 addSetHead (&cseSet, newCseDef (IC_RESULT (ic), pdic));
1537 /* eliminate this */
1538 remiCodeFromeBBlock (ebb, ic);
1543 if (IS_ITEMP (IC_RESULT (ic)))
1550 /* just add this as a previous expression except in */
1551 /* case of a pointer access in which case this is a */
1552 /* usage not a definition */
1553 if (!(POINTER_SET (ic)) && IC_RESULT (ic))
1555 deleteItemIf (&cseSet, ifDefSymIsX, IC_RESULT (ic));
1556 addSetHead (&cseSet, newCseDef (IC_RESULT (ic), ic));
1562 /* if assignment to a parameter which is not
1563 mine and type is a pointer then delete
1564 pointerGets to take care of aliasing */
1565 if (ASSIGNMENT (ic) &&
1566 OTHERS_PARM (OP_SYMBOL (IC_RESULT (ic))) &&
1567 IS_PTR (operandType (IC_RESULT (ic))))
1569 deleteGetPointers (&cseSet, &ptrSetSet, IC_RIGHT (ic), ebb);
1570 for (i = 0; i < count; ebbs[i++]->visited = 0);
1571 applyToSet (ebb->succList, delGetPointerSucc, IC_RIGHT (ic), ebb->dfnum);
1572 ebb->ptrsSet = bitVectSetBit (ebb->ptrsSet, IC_RIGHT (ic)->key);
1575 /* if this is a pointerget then see if we can replace
1576 this with a previously assigned pointer value */
1577 if (POINTER_GET (ic) &&
1578 !(IS_BITFIELD (OP_SYMBOL (IC_RESULT (ic))->etype) ||
1579 isOperandVolatile (IC_LEFT (ic), TRUE)))
1582 applyToSet (ptrSetSet, findPointerSet, IC_LEFT (ic), &pdop, IC_RESULT (ic));
1583 /* if we find it then locally replace all
1584 references to the result with what we assigned */
1587 replaceAllSymBySym (ic->next, IC_RESULT (ic), pdop, &ebb->ndompset);
1591 /* delete from the cseSet anything that has */
1592 /* operands matching the result of this */
1593 /* except in case of pointer access */
1594 if (!(POINTER_SET (ic)) && IC_RESULT (ic))
1596 deleteItemIf (&cseSet, ifOperandsHave, IC_RESULT (ic));
1597 /* delete any previous definitions */
1598 ebb->defSet = bitVectCplAnd (ebb->defSet, OP_DEFS (IC_RESULT (ic)));
1602 /* add the left & right to the defUse set */
1603 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)))
1605 OP_USES (IC_LEFT (ic)) =
1606 bitVectSetBit (OP_USES (IC_LEFT (ic)), ic->key);
1607 setUsesDefs (IC_LEFT (ic), ebb->defSet, ebb->outDefs, &ebb->usesDefs);
1611 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)))
1613 OP_USES (IC_RIGHT (ic)) =
1614 bitVectSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
1615 setUsesDefs (IC_RIGHT (ic), ebb->defSet, ebb->outDefs, &ebb->usesDefs);
1619 /* for the result it is special case, put the result */
1620 /* in the defuseSet if it a pointer or array access */
1621 if (POINTER_SET (defic))
1623 OP_USES (IC_RESULT (ic)) =
1624 bitVectSetBit (OP_USES (IC_RESULT (ic)), ic->key);
1625 setUsesDefs (IC_RESULT (ic), ebb->defSet, ebb->outDefs, &ebb->usesDefs);
1626 deleteItemIf (&cseSet, ifPointerGet, IC_RESULT (ic));
1627 ebb->ptrsSet = bitVectSetBit (ebb->ptrsSet, IC_RESULT (ic)->key);
1628 /* delete from inexpressions of all successors which
1629 have dfNum > than this block */
1630 for (i = 0; i < count; ebbs[i++]->visited = 0);
1631 applyToSet (ebb->succList, delGetPointerSucc, IC_RESULT (ic), ebb->dfnum);
1633 /* delete from cseSet all other pointer sets
1635 deleteItemIf (&ptrSetSet, ifPointerSet, IC_RESULT (ic));
1636 /* add to the local pointerset set */
1637 addSetHead (&ptrSetSet, newCseDef (IC_RESULT (ic), ic));
1640 /* add the result to defintion set */ if (IC_RESULT (ic))
1642 OP_DEFS (IC_RESULT (ic)) =
1643 bitVectSetBit (OP_DEFS (IC_RESULT (ic)), ic->key);
1644 ebb->defSet = bitVectSetBit (ebb->defSet, ic->key);
1645 ebb->outDefs = bitVectCplAnd (ebb->outDefs, OP_DEFS (IC_RESULT (ic)));
1646 ebb->ldefs = bitVectSetBit (ebb->ldefs, ic->key);
1650 /* if this is an addressof instruction then */
1651 /* put the symbol in the address of list & */
1652 /* delete it from the cseSet */
1653 if (defic->op == ADDRESS_OF)
1655 addSetHead (&ebb->addrOf, IC_LEFT (ic));
1656 deleteItemIf (&cseSet, ifDefSymIsX, IC_LEFT (ic));
1660 setToNull ((void **) &ebb->outExprs);
1661 ebb->outExprs = cseSet;
1662 ebb->outDefs = bitVectUnion (ebb->outDefs, ebb->defSet);
1663 ebb->ptrsSet = bitVectUnion (ebb->ptrsSet, ebb->inPtrsSet);
1667 /*-----------------------------------------------------------------*/
1668 /* cseAllBlocks - will sequentially go thru & do cse for all blocks */
1669 /*-----------------------------------------------------------------*/
1671 cseAllBlocks (eBBlock ** ebbs, int count)
1676 /* if optimization turned off */
1678 for (i = 0; i < count; i++)
1679 change += cseBBlock (ebbs[i], FALSE, ebbs, count);