1 /*-------------------------------------------------------------------------
2 SDCCopt.c - calls all the optimizations routines and does some of the
3 hackier transformations, these include translating iCodes
4 to function calls and replacing local variables with their
5 register equivalents etc. Also contains the driver routine
6 for dead code elimination
8 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1998)
10 This program is free software; you can redistribute it and/or modify it
11 under the terms of the GNU General Public License as published by the
12 Free Software Foundation; either version 2, or (at your option) any
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 In other words, you are welcome to use, share and improve this program.
25 You are forbidden to forbid anyone else to use, share and improve
26 what you give them. Help stamp out software-hoarding!
27 -------------------------------------------------------------------------*/
31 /*-----------------------------------------------------------------*/
32 /* global variables */
38 /*-----------------------------------------------------------------*/
39 /* printSymName - prints the symbol names */
40 /*-----------------------------------------------------------------*/
42 printSymName (void *vsym)
45 fprintf (stdout, " %s ", sym->name);
49 /*-----------------------------------------------------------------*/
50 /* cnvToFcall - does the actual conversion to function call */
51 /*-----------------------------------------------------------------*/
53 cnvToFcall (iCode * ic, eBBlock * ebp)
60 int lineno = ic->lineno;
63 ip = ic->next; /* insertion point */
64 /* remove it from the iCode */
65 remiCodeFromeBBlock (ebp, ic);
68 right = IC_RIGHT (ic);
104 /* if float support routines NOT compiled as reentrant */
105 if (!options.float_rent)
109 if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
111 newic = newiCode (SEND, IC_LEFT (ic), NULL);
112 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
116 newic = newiCode ('=', NULL, IC_LEFT (ic));
117 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
120 addiCodeToeBBlock (ebp, newic, ip);
121 newic->lineno = lineno;
124 if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
126 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
127 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
131 newic = newiCode ('=', NULL, IC_RIGHT (ic));
132 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type)->next);
134 addiCodeToeBBlock (ebp, newic, ip);
135 newic->lineno = lineno;
142 if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
144 newic = newiCode (SEND, right, NULL);
145 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
149 newic = newiCode (IPUSH, right, NULL);
152 bytesPushed += getSize(operandType(right));
155 addiCodeToeBBlock (ebp, newic, ip);
156 newic->lineno = lineno;
158 /* insert push left */
159 if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
161 newic = newiCode (SEND, left, NULL);
162 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
166 newic = newiCode (IPUSH, left, NULL);
169 bytesPushed += getSize(operandType(left));
171 addiCodeToeBBlock (ebp, newic, ip);
172 newic->lineno = lineno;
174 /* insert the call */
175 newic = newiCode (CALL, operandFromSymbol (func), NULL);
176 IC_RESULT (newic) = IC_RESULT (ic);
177 newic->lineno = lineno;
178 newic->parmBytes+=bytesPushed;
179 addiCodeToeBBlock (ebp, newic, ip);
182 /*-----------------------------------------------------------------*/
183 /* cnvToFloatCast - converts casts to floats to function calls */
184 /*-----------------------------------------------------------------*/
186 cnvToFloatCast (iCode * ic, eBBlock * ebp)
190 sym_link *type = operandType (IC_RIGHT (ic));
191 int linenno = ic->lineno;
196 /* remove it from the iCode */
197 remiCodeFromeBBlock (ebp, ic);
198 /* depending on the type */
199 for (bwd = 0; bwd < 3; bwd++)
201 for (su = 0; su < 2; su++)
203 if (compareType (type, __multypes[bwd][su]) == 1)
205 func = __conv[0][bwd][su];
213 /* if float support routines NOT compiled as reentrant */
214 if (!options.float_rent)
217 if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
219 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
220 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
224 newic = newiCode ('=', NULL, IC_RIGHT (ic));
225 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
227 addiCodeToeBBlock (ebp, newic, ip);
228 newic->lineno = linenno;
234 if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
235 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
236 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
240 newic = newiCode (IPUSH, IC_RIGHT (ic), NULL);
242 bytesPushed += getSize(operandType(IC_RIGHT(ic)));
244 addiCodeToeBBlock (ebp, newic, ip);
245 newic->lineno = linenno;
250 newic = newiCode (CALL, operandFromSymbol (func), NULL);
251 IC_RESULT (newic) = IC_RESULT (ic);
252 newic->parmBytes+=bytesPushed;
253 addiCodeToeBBlock (ebp, newic, ip);
254 newic->lineno = linenno;
258 /*-----------------------------------------------------------------*/
259 /* cnvFromFloatCast - converts casts From floats to function calls */
260 /*-----------------------------------------------------------------*/
262 cnvFromFloatCast (iCode * ic, eBBlock * ebp)
266 sym_link *type = operandType (IC_LEFT (ic));
267 int lineno = ic->lineno;
272 /* remove it from the iCode */
273 remiCodeFromeBBlock (ebp, ic);
275 /* depending on the type */
276 for (bwd = 0; bwd < 3; bwd++)
278 for (su = 0; su < 2; su++)
280 if (compareType (type, __multypes[bwd][su]) == 1)
282 func = __conv[1][bwd][su];
290 /* if float support routines NOT compiled as reentrant */
291 if (!options.float_rent)
294 if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
295 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
296 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
300 newic = newiCode ('=', NULL, IC_RIGHT (ic));
301 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
303 addiCodeToeBBlock (ebp, newic, ip);
304 newic->lineno = lineno;
311 if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
312 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
313 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
317 newic = newiCode (IPUSH, IC_RIGHT (ic), NULL);
319 bytesPushed += getSize(operandType(IC_RIGHT(ic)));
321 addiCodeToeBBlock (ebp, newic, ip);
322 newic->lineno = lineno;
327 newic = newiCode (CALL, operandFromSymbol (func), NULL);
328 IC_RESULT (newic) = IC_RESULT (ic);
329 newic->parmBytes+=bytesPushed;
330 addiCodeToeBBlock (ebp, newic, ip);
331 newic->lineno = lineno;
335 extern operand *geniCodeRValue (operand *, bool);
337 /*-----------------------------------------------------------------*/
338 /* convilong - converts int or long mults or divs to fcalls */
339 /*-----------------------------------------------------------------*/
341 convilong (iCode * ic, eBBlock * ebp, sym_link * type, int op)
344 iCode *ip = ic->next;
346 int lineno = ic->lineno;
351 // Easy special case which avoids function call: modulo by a literal power
352 // of two can be replaced by a bitwise AND.
353 if (op == '%' && isOperandLiteral(IC_RIGHT(ic)))
355 unsigned litVal = (unsigned)(operandLitValue(IC_RIGHT(ic)));
357 // See if literal value is a power of 2.
358 while (litVal && !(litVal & 1))
364 // discard first high bit set.
371 IC_RIGHT(ic) = operandFromLit(operandLitValue(IC_RIGHT(ic)) - 1);
376 remiCodeFromeBBlock (ebp, ic);
379 /* depending on the type */
380 for (bwd = 0; bwd < 3; bwd++)
382 for (su = 0; su < 2; su++)
384 if (compareType (type, __multypes[bwd][su]) == 1)
387 func = __muldiv[0][bwd][su];
389 func = __muldiv[1][bwd][su];
391 func = __muldiv[2][bwd][su];
393 func = __rlrr[1][bwd][su];
395 func = __rlrr[0][bwd][su];
396 else if (op == RIGHT_OP)
397 func = __rlrr[1][bwd][su];
398 else if (op == LEFT_OP)
399 func = __rlrr[0][bwd][su];
408 /* if int & long support routines NOT compiled as reentrant */
409 if (!options.intlong_rent)
412 if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
413 newic = newiCode (SEND, IC_LEFT (ic), NULL);
414 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
418 newic = newiCode ('=', NULL, IC_LEFT (ic));
419 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
421 addiCodeToeBBlock (ebp, newic, ip);
422 newic->lineno = lineno;
425 if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype)) {
426 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
427 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
431 newic = newiCode ('=', NULL, IC_RIGHT (ic));
432 IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type)->next);
434 addiCodeToeBBlock (ebp, newic, ip);
435 newic->lineno = lineno;
440 /* compiled as reentrant then push */
442 if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
444 newic = newiCode (SEND, IC_RIGHT (ic), NULL);
445 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
449 newic = newiCode (IPUSH, IC_RIGHT (ic), NULL);
452 bytesPushed += getSize(operandType(IC_RIGHT(ic)));
454 addiCodeToeBBlock (ebp, newic, ip);
455 newic->lineno = lineno;
457 /* insert push left */
458 if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
460 newic = newiCode (SEND, IC_LEFT (ic), NULL);
461 newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
465 newic = newiCode (IPUSH, IC_LEFT (ic), NULL);
468 bytesPushed += getSize(operandType(IC_LEFT(ic)));
470 addiCodeToeBBlock (ebp, newic, ip);
471 newic->lineno = lineno;
476 newic = newiCode (CALL, operandFromSymbol (func), NULL);
477 IC_RESULT (newic) = IC_RESULT (ic);
478 newic->lineno = lineno;
479 newic->parmBytes+=bytesPushed; // to clear the stack after the call
480 addiCodeToeBBlock (ebp, newic, ip);
483 /*-----------------------------------------------------------------*/
484 /* convertToFcall - converts some operations to fcalls */
485 /*-----------------------------------------------------------------*/
487 convertToFcall (eBBlock ** ebbs, int count)
491 /* for all blocks do */
492 for (i = 0; i < count; i++)
496 /* for all instructions in the block do */
497 for (ic = ebbs[i]->sch; ic; ic = ic->next)
500 /* floating point operations are
501 converted to function calls */
502 if ((IS_CONDITIONAL (ic) ||
503 IS_ARITHMETIC_OP (ic)) &&
504 (IS_FLOAT (operandType (IC_RIGHT (ic)))))
507 cnvToFcall (ic, ebbs[i]);
510 /* casting is a little different */
513 if (IS_FLOAT (operandType (IC_RIGHT (ic))))
514 cnvFromFloatCast (ic, ebbs[i]);
515 else if (IS_FLOAT (operandType (IC_LEFT (ic))))
516 cnvToFloatCast (ic, ebbs[i]);
519 /* if long / int mult or divide or mod */
520 if (ic->op == '*' || ic->op == '/' || ic->op == '%')
522 sym_link *leftType = operandType (IC_LEFT (ic));
524 if (IS_INTEGRAL (leftType) && getSize (leftType) > port->support.muldiv)
526 sym_link *rightType = operandType (IC_RIGHT (ic));
528 if (port->hasNativeMulFor != NULL &&
529 port->hasNativeMulFor (ic, leftType, rightType))
531 /* Leave as native */
535 convilong (ic, ebbs[i], leftType, ic->op);
540 if (ic->op == RRC || ic->op == RLC || ic->op == LEFT_OP || ic->op == RIGHT_OP)
542 sym_link *type = operandType (IC_LEFT (ic));
544 if (IS_INTEGRAL (type) && getSize (type) > port->support.shift && port->support.shift >= 0)
546 convilong (ic, ebbs[i], type, ic->op);
553 /*-----------------------------------------------------------------*/
554 /* isLocalWithoutDef - return 1 if sym might be used without a */
556 /*-----------------------------------------------------------------*/
558 isLocalWithoutDef (symbol * sym)
563 if (IS_STATIC (sym->etype))
566 if (IS_VOLATILE (sym->type))
572 if (IS_AGGREGATE (sym->type))
581 /*-----------------------------------------------------------------*/
582 /* replaceRegEqv - replace all local variables with their reqv */
583 /*-----------------------------------------------------------------*/
585 replaceRegEqv (eBBlock ** ebbs, int count)
589 /* Update the symbols' def bitvector so we know if there is */
590 /* a defining iCode or not. Only replace a local variable */
591 /* with its register equivalent if there is a defining iCode; */
592 /* otherwise, the port's register allocater may choke. */
593 cseAllBlocks (ebbs, count, TRUE);
595 for (i = 0; i < count; i++)
600 for (ic = ebbs[i]->sch; ic; ic = ic->next)
609 IS_TRUE_SYMOP (IC_COND (ic)) &&
610 isLocalWithoutDef (OP_SYMBOL (IC_COND (ic))))
612 werror (W_LOCAL_NOINIT,
613 OP_SYMBOL (IC_COND (ic))->name,
614 ic->filename, ic->lineno);
615 OP_REQV (IC_COND (ic)) = NULL;
616 OP_SYMBOL (IC_COND (ic))->allocreq = 1;
619 if (IS_TRUE_SYMOP (IC_COND (ic)) &&
620 OP_REQV (IC_COND (ic)))
621 IC_COND (ic) = opFromOpWithDU (OP_REQV (IC_COND (ic)),
622 OP_SYMBOL (IC_COND (ic))->defs,
623 OP_SYMBOL (IC_COND (ic))->uses);
629 if (ic->op == JUMPTABLE)
631 if (IC_JTCOND (ic) &&
632 IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
633 isLocalWithoutDef (OP_SYMBOL (IC_JTCOND (ic))))
635 werror (W_LOCAL_NOINIT,
636 OP_SYMBOL (IC_JTCOND (ic))->name,
637 ic->filename, ic->lineno);
638 OP_REQV (IC_JTCOND (ic)) = NULL;
639 OP_SYMBOL (IC_JTCOND (ic))->allocreq = 1;
642 if (IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
643 OP_REQV (IC_JTCOND (ic)))
644 IC_JTCOND (ic) = opFromOpWithDU (OP_REQV (IC_JTCOND (ic)),
645 OP_SYMBOL (IC_JTCOND (ic))->defs,
646 OP_SYMBOL (IC_JTCOND (ic))->uses);
650 if (ic->op == RECEIVE)
652 if (OP_SYMBOL (IC_RESULT (ic))->addrtaken)
653 OP_SYMBOL (IC_RESULT (ic))->isspilt = 1;
657 if (IC_RESULT (ic) &&
658 IS_TRUE_SYMOP (IC_RESULT (ic)) &&
659 OP_REQV (IC_RESULT (ic)))
661 if (POINTER_SET (ic))
663 IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
664 OP_SYMBOL (IC_RESULT (ic))->defs,
665 OP_SYMBOL (IC_RESULT (ic))->uses);
666 IC_RESULT (ic)->isaddr = 1;
669 IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
670 OP_SYMBOL (IC_RESULT (ic))->defs,
671 OP_SYMBOL (IC_RESULT (ic))->uses);
675 IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
676 isLocalWithoutDef (OP_SYMBOL (IC_RIGHT (ic))))
678 werror (W_LOCAL_NOINIT,
679 OP_SYMBOL (IC_RIGHT (ic))->name,
680 ic->filename, ic->lineno);
681 OP_REQV (IC_RIGHT (ic)) = NULL;
682 OP_SYMBOL (IC_RIGHT (ic))->allocreq = 1;
686 IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
687 OP_REQV (IC_RIGHT (ic)))
689 IC_RIGHT (ic) = opFromOpWithDU (OP_REQV (IC_RIGHT (ic)),
690 OP_SYMBOL (IC_RIGHT (ic))->defs,
691 OP_SYMBOL (IC_RIGHT (ic))->uses);
692 IC_RIGHT (ic)->isaddr = 0;
696 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
697 isLocalWithoutDef (OP_SYMBOL (IC_LEFT (ic))))
699 werror (W_LOCAL_NOINIT,
700 OP_SYMBOL (IC_LEFT (ic))->name,
701 ic->filename, ic->lineno);
702 OP_REQV (IC_LEFT (ic)) = NULL;
703 OP_SYMBOL (IC_LEFT (ic))->allocreq = 1;
707 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
708 OP_REQV (IC_LEFT (ic)))
710 IC_LEFT (ic) = opFromOpWithDU (OP_REQV (IC_LEFT (ic)),
711 OP_SYMBOL (IC_LEFT (ic))->defs,
712 OP_SYMBOL (IC_LEFT (ic))->uses);
713 IC_LEFT (ic)->isaddr = 0;
719 /*-----------------------------------------------------------------*/
720 /* killDeadCode - eliminates dead assignments */
721 /*-----------------------------------------------------------------*/
723 killDeadCode (eBBlock ** ebbs, int count)
730 /* basic algorithm :- */
731 /* first the exclusion rules :- */
732 /* 1. if result is a global or volatile then skip */
733 /* 2. if assignment and result is a temp & isaddr then skip */
734 /* since this means array & pointer access, will be taken */
735 /* care of by alias analysis. */
736 /* 3. if the result is used in the remainder of the block skip */
737 /* 4. if this definition does not reach the end of the block */
738 /* i.e. the result is not present in the outExprs then KILL */
739 /* 5. if it reaches the end of block & is used by some success */
742 /* this whole process is carried on iteratively till no change */
747 /* for all blocks do */
748 for (i = 0; i < count; i++)
752 /* for all instructions in the block do */
753 for (ic = ebbs[i]->sch; ic; ic = ic->next)
761 ic->op == DUMMY_READ_VOLATILE ||
762 ic->op == CRITICAL ||
763 ic->op == ENDCRITICAL)
766 /* if the result is volatile then continue */
767 if (IC_RESULT (ic) && isOperandVolatile (IC_RESULT (ic), FALSE))
770 /* if the result is a temp & isaddr then skip */
771 if (IC_RESULT (ic) && POINTER_SET (ic))
774 if (POINTER_GET (ic) && IS_VOLATILE (operandType (IC_LEFT (ic))->next))
777 /* if the result is used in the remainder of the */
778 /* block then skip */
779 if (usedInRemaining (IC_RESULT (ic), ic->next))
782 /* does this definition reach the end of the block
783 or the usage is zero then we can kill */
784 if (!bitVectBitValue (ebbs[i]->outDefs, ic->key))
785 kill = 1; /* if not we can kill it */
788 /* if this is a global variable or function parameter */
789 /* we cannot kill anyway */
790 if (isOperandGlobal (IC_RESULT (ic)) ||
791 (OP_SYMBOL (IC_RESULT (ic))->_isparm &&
792 !OP_SYMBOL (IC_RESULT (ic))->ismyparm))
795 /* if we are sure there are no usages */
796 if (bitVectIsZero (OP_USES (IC_RESULT (ic))))
802 /* reset visited flag */
803 for (j = 0; j < count; ebbs[j++]->visited = 0);
805 /* find out if this definition is alive */
806 if (applyToSet (ebbs[i]->succList,
815 /* kill this one if required */
821 remiCodeFromeBBlock (ebbs[i], ic);
823 /* now delete from defUseSet */
824 deleteItemIf (&ebbs[i]->outExprs, ifDiCodeIsX, ic);
825 bitVectUnSetBit (ebbs[i]->outDefs, ic->key);
827 /* and defset of the block */
828 bitVectUnSetBit (ebbs[i]->defSet, ic->key);
830 /* for the left & right remove the usage */
831 if (IS_SYMOP (IC_LEFT (ic)))
832 bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
834 if (IS_SYMOP (IC_RIGHT (ic)))
835 bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
838 } /* end of all instructions */
840 if (!ebbs[i]->sch && !ebbs[i]->noPath)
841 disconBBlock (ebbs[i], ebbs, count);
843 } /* end of for all blocks */
847 } /* end of while(1) */
852 /*-----------------------------------------------------------------*/
853 /* printCyclomatic - prints the cyclomatic information */
854 /*-----------------------------------------------------------------*/
856 printCyclomatic (eBBlock ** ebbs, int count)
858 int nEdges = elementsInSet (graphEdges);
861 for (i = 0; i < count; i++)
862 nNodes += (!ebbs[i]->noPath);
864 /* print the information */
865 werror (I_CYCLOMATIC, currFunc->name, nEdges, nNodes, nEdges - nNodes + 2);
868 /*-----------------------------------------------------------------*/
869 /* discardDeadParamReceives - remove any RECEIVE opcodes which */
870 /* refer to dead variables. */
871 /*-----------------------------------------------------------------*/
873 discardDeadParamReceives (eBBlock ** ebbs, int count)
879 for (i = 0; i < count; i++)
881 for (ic = ebbs[i]->sch; ic; ic = ic->next)
883 if (ic->op == RECEIVE)
885 if (IC_RESULT (ic) && OP_SYMBOL (IC_RESULT (ic))
886 && !OP_SYMBOL (IC_RESULT (ic))->used)
889 fprintf (stderr, "discarding dead receive for %s\n",
890 OP_SYMBOL (IC_RESULT (ic))->name);
892 dummyIcode.next = ic->next;
893 remiCodeFromeBBlock (ebbs[i], ic);
901 /*-----------------------------------------------------------------*/
902 /* eBBlockFromiCode - creates extended basic blocks from iCode */
903 /* will return an array of eBBlock pointers */
904 /*-----------------------------------------------------------------*/
906 eBBlockFromiCode (iCode * ic)
908 eBBlock **ebbs = NULL;
916 /* if nothing passed then return nothing */
923 /* optimize the chain for labels & gotos
924 this will eliminate redundant labels and
925 will change jump to jumps by jumps */
926 ic = iCodeLabelOptimize (ic);
928 /* break it down into basic blocks */
929 ebbs = iCodeBreakDown (ic, &count);
932 /* hash the iCode keys so that we can quickly index */
933 /* them in the rest of the optimization steps */
934 setToNull ((void *) &iCodehTab);
935 iCodehTab = newHashTable (iCodeKey);
936 hashiCodeKeys (ebbs, count);
938 /* compute the control flow */
939 computeControlFlow (ebbs, count, 0);
941 /* dumpraw if asked for */
942 if (options.dump_raw)
943 dumpEbbsToFileExt (DUMP_RAW0, ebbs, count);
945 /* replace the local variables with their
946 register equivalents : the liveRange computation
947 along with the register allocation will determine
948 if it finally stays in the registers */
949 replaceRegEqv (ebbs, count);
951 /* create loop regions */
952 loops = createLoopRegions (ebbs, count);
954 /* dumpraw if asked for */
955 if (options.dump_raw)
956 dumpEbbsToFileExt (DUMP_RAW1, ebbs, count);
958 /* do common subexpression elimination for each block */
959 change = cseAllBlocks (ebbs, saveCount, FALSE);
961 /* dumpraw if asked for */
962 if (options.dump_raw)
963 dumpEbbsToFileExt (DUMP_CSE, ebbs, count);
965 /* compute the data flow */
966 computeDataFlow (ebbs, saveCount);
968 /* dumpraw if asked for */
969 if (options.dump_raw)
970 dumpEbbsToFileExt (DUMP_DFLOW, ebbs, count);
972 /* global common subexpression elimination */
973 if (optimize.global_cse)
975 change += cseAllBlocks (ebbs, saveCount, FALSE);
976 if (options.dump_gcse)
977 dumpEbbsToFileExt (DUMP_GCSE, ebbs, saveCount);
981 // compute the dataflow only
982 assert(cseAllBlocks (ebbs, saveCount, TRUE)==0);
985 kchange = killDeadCode (ebbs, saveCount);
987 if (options.dump_kill)
988 dumpEbbsToFileExt (DUMP_DEADCODE, ebbs, count);
990 /* do loop optimizations */
991 change += (lchange = loopOptimizations (loops, ebbs, count));
992 if (options.dump_loop)
993 dumpEbbsToFileExt (DUMP_LOOP, ebbs, count);
995 /* recompute the data flow and apply global cse again
996 if loops optimizations or dead code caused a change:
997 loops will brings out of the loop which then may be
998 available for use in the later blocks: dead code
999 elimination could potentially disconnect some blocks
1000 conditional flow may be efected so we need to apply
1001 subexpression once more */
1002 if (lchange || kchange)
1004 computeDataFlow (ebbs, saveCount);
1005 change += cseAllBlocks (ebbs, saveCount, FALSE);
1006 if (options.dump_loop)
1007 dumpEbbsToFileExt (DUMP_LOOPG, ebbs, count);
1009 /* if loop optimizations caused a change then do
1010 dead code elimination once more : this will
1011 get rid of the extra assignments to the induction
1012 variables created during loop optimizations */
1013 killDeadCode (ebbs, saveCount);
1015 if (options.dump_loop)
1016 dumpEbbsToFileExt (DUMP_LOOPD, ebbs, count);
1020 /* sort it back by block number */
1021 qsort (ebbs, saveCount, sizeof (eBBlock *), bbNumCompare);
1023 if (!options.lessPedantic) {
1024 // this is a good place to check missing return values
1026 // the user is on his own with naked functions...
1027 if (!IS_VOID(currFunc->etype)
1028 && !FUNC_ISNAKED(currFunc->type)) {
1030 // make sure all predecessors of the last block end in a return
1031 for (bp=setFirstItem(ebbs[saveCount-1]->predList);
1033 bp=setNextItem(ebbs[saveCount-1]->predList)) {
1034 if (bp->ech->op != RETURN) {
1035 werror (W_VOID_FUNC, currFunc->name);
1042 /* if cyclomatic info requested then print it */
1043 if (options.cyclomatic)
1044 printCyclomatic (ebbs, saveCount);
1046 /* convert operations with support routines
1047 written in C to function calls : Iam doing
1048 this at this point since I want all the
1049 operations to be as they are for optimzations */
1050 convertToFcall (ebbs, count);
1052 /* compute the live ranges */
1053 computeLiveRanges (ebbs, count);
1055 if (options.dump_range)
1056 dumpEbbsToFileExt (DUMP_RANGE, ebbs, count);
1058 /* Now that we have the live ranges, discard parameter
1059 * receives for unused parameters.
1061 discardDeadParamReceives (ebbs, count);
1063 /* allocate registers & generate code */
1064 port->assignRegisters (ebbs, count);
1066 /* throw away blocks */
1067 setToNull ((void *) &graphEdges);
1074 /* (add-hook 'c-mode-hook (lambda () (setq c-basic-offset 4))) */