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))
578 /*-----------------------------------------------------------------*/
579 /* replaceRegEqv - replace all local variables with their reqv */
580 /*-----------------------------------------------------------------*/
582 replaceRegEqv (eBBlock ** ebbs, int count)
586 /* Update the symbols' def bitvector so we know if there is */
587 /* a defining iCode or not. Only replace a local variable */
588 /* with its register equivalent if there is a defining iCode; */
589 /* otherwise, the port's register allocater may choke. */
590 cseAllBlocks (ebbs, count, TRUE);
592 for (i = 0; i < count; i++)
597 for (ic = ebbs[i]->sch; ic; ic = ic->next)
606 IS_TRUE_SYMOP (IC_COND (ic)) &&
607 isLocalWithoutDef (OP_SYMBOL (IC_COND (ic))))
609 werror (W_LOCAL_NOINIT,
610 OP_SYMBOL (IC_COND (ic))->name,
611 ic->filename, ic->lineno);
612 OP_REQV (IC_COND (ic)) = NULL;
613 OP_SYMBOL (IC_COND (ic))->allocreq = 1;
616 if (IS_TRUE_SYMOP (IC_COND (ic)) &&
617 OP_REQV (IC_COND (ic)))
618 IC_COND (ic) = opFromOpWithDU (OP_REQV (IC_COND (ic)),
619 OP_SYMBOL (IC_COND (ic))->defs,
620 OP_SYMBOL (IC_COND (ic))->uses);
626 if (ic->op == JUMPTABLE)
628 if (IC_JTCOND (ic) &&
629 IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
630 isLocalWithoutDef (OP_SYMBOL (IC_JTCOND (ic))))
632 werror (W_LOCAL_NOINIT,
633 OP_SYMBOL (IC_JTCOND (ic))->name,
634 ic->filename, ic->lineno);
635 OP_REQV (IC_JTCOND (ic)) = NULL;
636 OP_SYMBOL (IC_JTCOND (ic))->allocreq = 1;
639 if (IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
640 OP_REQV (IC_JTCOND (ic)))
641 IC_JTCOND (ic) = opFromOpWithDU (OP_REQV (IC_JTCOND (ic)),
642 OP_SYMBOL (IC_JTCOND (ic))->defs,
643 OP_SYMBOL (IC_JTCOND (ic))->uses);
647 if (ic->op == RECEIVE)
649 if (OP_SYMBOL (IC_RESULT (ic))->addrtaken)
650 OP_SYMBOL (IC_RESULT (ic))->isspilt = 1;
654 if (IC_RESULT (ic) &&
655 IS_TRUE_SYMOP (IC_RESULT (ic)) &&
656 OP_REQV (IC_RESULT (ic)))
658 if (POINTER_SET (ic))
660 IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
661 OP_SYMBOL (IC_RESULT (ic))->defs,
662 OP_SYMBOL (IC_RESULT (ic))->uses);
663 IC_RESULT (ic)->isaddr = 1;
666 IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
667 OP_SYMBOL (IC_RESULT (ic))->defs,
668 OP_SYMBOL (IC_RESULT (ic))->uses);
672 IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
673 isLocalWithoutDef (OP_SYMBOL (IC_RIGHT (ic))))
675 werror (W_LOCAL_NOINIT,
676 OP_SYMBOL (IC_RIGHT (ic))->name,
677 ic->filename, ic->lineno);
678 OP_REQV (IC_RIGHT (ic)) = NULL;
679 OP_SYMBOL (IC_RIGHT (ic))->allocreq = 1;
683 IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
684 OP_REQV (IC_RIGHT (ic)))
686 IC_RIGHT (ic) = opFromOpWithDU (OP_REQV (IC_RIGHT (ic)),
687 OP_SYMBOL (IC_RIGHT (ic))->defs,
688 OP_SYMBOL (IC_RIGHT (ic))->uses);
689 IC_RIGHT (ic)->isaddr = 0;
693 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
694 isLocalWithoutDef (OP_SYMBOL (IC_LEFT (ic))))
696 werror (W_LOCAL_NOINIT,
697 OP_SYMBOL (IC_LEFT (ic))->name,
698 ic->filename, ic->lineno);
699 OP_REQV (IC_LEFT (ic)) = NULL;
700 OP_SYMBOL (IC_LEFT (ic))->allocreq = 1;
704 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
705 OP_REQV (IC_LEFT (ic)))
707 IC_LEFT (ic) = opFromOpWithDU (OP_REQV (IC_LEFT (ic)),
708 OP_SYMBOL (IC_LEFT (ic))->defs,
709 OP_SYMBOL (IC_LEFT (ic))->uses);
710 IC_LEFT (ic)->isaddr = 0;
716 /*-----------------------------------------------------------------*/
717 /* killDeadCode - eliminates dead assignments */
718 /*-----------------------------------------------------------------*/
720 killDeadCode (eBBlock ** ebbs, int count)
727 /* basic algorithm :- */
728 /* first the exclusion rules :- */
729 /* 1. if result is a global or volatile then skip */
730 /* 2. if assignment and result is a temp & isaddr then skip */
731 /* since this means array & pointer access, will be taken */
732 /* care of by alias analysis. */
733 /* 3. if the result is used in the remainder of the block skip */
734 /* 4. if this definition does not reach the end of the block */
735 /* i.e. the result is not present in the outExprs then KILL */
736 /* 5. if it reaches the end of block & is used by some success */
739 /* this whole process is carried on iteratively till no change */
744 /* for all blocks do */
745 for (i = 0; i < count; i++)
749 /* for all instructions in the block do */
750 for (ic = ebbs[i]->sch; ic; ic = ic->next)
758 ic->op == DUMMY_READ_VOLATILE ||
759 ic->op == CRITICAL ||
760 ic->op == ENDCRITICAL)
763 /* if the result is volatile then continue */
764 if (IC_RESULT (ic) && isOperandVolatile (IC_RESULT (ic), FALSE))
767 /* if the result is a temp & isaddr then skip */
768 if (IC_RESULT (ic) && POINTER_SET (ic))
771 if (POINTER_GET (ic) && IS_VOLATILE (operandType (IC_LEFT (ic))->next))
774 /* if the result is used in the remainder of the */
775 /* block then skip */
776 if (usedInRemaining (IC_RESULT (ic), ic->next))
779 /* does this definition reach the end of the block
780 or the usage is zero then we can kill */
781 if (!bitVectBitValue (ebbs[i]->outDefs, ic->key))
782 kill = 1; /* if not we can kill it */
785 /* if this is a global variable or function parameter */
786 /* we cannot kill anyway */
787 if (isOperandGlobal (IC_RESULT (ic)) ||
788 (OP_SYMBOL (IC_RESULT (ic))->_isparm &&
789 !OP_SYMBOL (IC_RESULT (ic))->ismyparm))
792 /* if we are sure there are no usages */
793 if (bitVectIsZero (OP_USES (IC_RESULT (ic))))
799 /* reset visited flag */
800 for (j = 0; j < count; ebbs[j++]->visited = 0);
802 /* find out if this definition is alive */
803 if (applyToSet (ebbs[i]->succList,
812 /* kill this one if required */
818 remiCodeFromeBBlock (ebbs[i], ic);
820 /* now delete from defUseSet */
821 deleteItemIf (&ebbs[i]->outExprs, ifDiCodeIsX, ic);
822 bitVectUnSetBit (ebbs[i]->outDefs, ic->key);
824 /* and defset of the block */
825 bitVectUnSetBit (ebbs[i]->defSet, ic->key);
827 /* for the left & right remove the usage */
828 if (IS_SYMOP (IC_LEFT (ic)))
829 bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
831 if (IS_SYMOP (IC_RIGHT (ic)))
832 bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
835 } /* end of all instructions */
837 if (!ebbs[i]->sch && !ebbs[i]->noPath)
838 disconBBlock (ebbs[i], ebbs, count);
840 } /* end of for all blocks */
844 } /* end of while(1) */
849 /*-----------------------------------------------------------------*/
850 /* printCyclomatic - prints the cyclomatic information */
851 /*-----------------------------------------------------------------*/
853 printCyclomatic (eBBlock ** ebbs, int count)
855 int nEdges = elementsInSet (graphEdges);
858 for (i = 0; i < count; i++)
859 nNodes += (!ebbs[i]->noPath);
861 /* print the information */
862 werror (I_CYCLOMATIC, currFunc->name, nEdges, nNodes, nEdges - nNodes + 2);
865 /*-----------------------------------------------------------------*/
866 /* discardDeadParamReceives - remove any RECEIVE opcodes which */
867 /* refer to dead variables. */
868 /*-----------------------------------------------------------------*/
870 discardDeadParamReceives (eBBlock ** ebbs, int count)
876 for (i = 0; i < count; i++)
878 for (ic = ebbs[i]->sch; ic; ic = ic->next)
880 if (ic->op == RECEIVE)
882 if (IC_RESULT (ic) && OP_SYMBOL (IC_RESULT (ic))
883 && !OP_SYMBOL (IC_RESULT (ic))->used)
886 fprintf (stderr, "discarding dead receive for %s\n",
887 OP_SYMBOL (IC_RESULT (ic))->name);
889 dummyIcode.next = ic->next;
890 remiCodeFromeBBlock (ebbs[i], ic);
898 /*-----------------------------------------------------------------*/
899 /* eBBlockFromiCode - creates extended basic blocks from iCode */
900 /* will return an array of eBBlock pointers */
901 /*-----------------------------------------------------------------*/
903 eBBlockFromiCode (iCode * ic)
905 eBBlock **ebbs = NULL;
913 /* if nothing passed then return nothing */
920 /* optimize the chain for labels & gotos
921 this will eliminate redundant labels and
922 will change jump to jumps by jumps */
923 ic = iCodeLabelOptimize (ic);
925 /* break it down into basic blocks */
926 ebbs = iCodeBreakDown (ic, &count);
929 /* hash the iCode keys so that we can quickly index */
930 /* them in the rest of the optimization steps */
931 setToNull ((void *) &iCodehTab);
932 iCodehTab = newHashTable (iCodeKey);
933 hashiCodeKeys (ebbs, count);
935 /* compute the control flow */
936 computeControlFlow (ebbs, count, 0);
938 /* dumpraw if asked for */
939 if (options.dump_raw)
940 dumpEbbsToFileExt (DUMP_RAW0, ebbs, count);
942 /* replace the local variables with their
943 register equivalents : the liveRange computation
944 along with the register allocation will determine
945 if it finally stays in the registers */
946 replaceRegEqv (ebbs, count);
948 /* create loop regions */
949 loops = createLoopRegions (ebbs, count);
951 /* dumpraw if asked for */
952 if (options.dump_raw)
953 dumpEbbsToFileExt (DUMP_RAW1, ebbs, count);
955 /* do common subexpression elimination for each block */
956 change = cseAllBlocks (ebbs, saveCount, FALSE);
958 /* dumpraw if asked for */
959 if (options.dump_raw)
960 dumpEbbsToFileExt (DUMP_CSE, ebbs, count);
962 /* compute the data flow */
963 computeDataFlow (ebbs, saveCount);
965 /* dumpraw if asked for */
966 if (options.dump_raw)
967 dumpEbbsToFileExt (DUMP_DFLOW, ebbs, count);
969 /* global common subexpression elimination */
970 if (optimize.global_cse)
972 change += cseAllBlocks (ebbs, saveCount, FALSE);
973 if (options.dump_gcse)
974 dumpEbbsToFileExt (DUMP_GCSE, ebbs, saveCount);
978 // compute the dataflow only
979 assert(cseAllBlocks (ebbs, saveCount, TRUE)==0);
982 kchange = killDeadCode (ebbs, saveCount);
984 if (options.dump_kill)
985 dumpEbbsToFileExt (DUMP_DEADCODE, ebbs, count);
987 /* do loop optimizations */
988 change += (lchange = loopOptimizations (loops, ebbs, count));
989 if (options.dump_loop)
990 dumpEbbsToFileExt (DUMP_LOOP, ebbs, count);
992 /* recompute the data flow and apply global cse again
993 if loops optimizations or dead code caused a change:
994 loops will brings out of the loop which then may be
995 available for use in the later blocks: dead code
996 elimination could potentially disconnect some blocks
997 conditional flow may be efected so we need to apply
998 subexpression once more */
999 if (lchange || kchange)
1001 computeDataFlow (ebbs, saveCount);
1002 change += cseAllBlocks (ebbs, saveCount, FALSE);
1003 if (options.dump_loop)
1004 dumpEbbsToFileExt (DUMP_LOOPG, ebbs, count);
1006 /* if loop optimizations caused a change then do
1007 dead code elimination once more : this will
1008 get rid of the extra assignments to the induction
1009 variables created during loop optimizations */
1010 killDeadCode (ebbs, saveCount);
1012 if (options.dump_loop)
1013 dumpEbbsToFileExt (DUMP_LOOPD, ebbs, count);
1017 /* sort it back by block number */
1018 qsort (ebbs, saveCount, sizeof (eBBlock *), bbNumCompare);
1020 if (!options.lessPedantic) {
1021 // this is a good place to check missing return values
1023 // the user is on his own with naked functions...
1024 if (!IS_VOID(currFunc->etype)
1025 && !FUNC_ISNAKED(currFunc->type)) {
1027 // make sure all predecessors of the last block end in a return
1028 for (bp=setFirstItem(ebbs[saveCount-1]->predList);
1030 bp=setNextItem(ebbs[saveCount-1]->predList)) {
1031 if (bp->ech->op != RETURN) {
1032 werror (W_VOID_FUNC, currFunc->name);
1039 /* if cyclomatic info requested then print it */
1040 if (options.cyclomatic)
1041 printCyclomatic (ebbs, saveCount);
1043 /* convert operations with support routines
1044 written in C to function calls : Iam doing
1045 this at this point since I want all the
1046 operations to be as they are for optimzations */
1047 convertToFcall (ebbs, count);
1049 /* compute the live ranges */
1050 computeLiveRanges (ebbs, count);
1052 if (options.dump_range)
1053 dumpEbbsToFileExt (DUMP_RANGE, ebbs, count);
1055 /* Now that we have the live ranges, discard parameter
1056 * receives for unused parameters.
1058 discardDeadParamReceives (ebbs, count);
1060 /* allocate registers & generate code */
1061 port->assignRegisters (ebbs, count);
1063 /* throw away blocks */
1064 setToNull ((void *) &graphEdges);
1071 /* (add-hook 'c-mode-hook (lambda () (setq c-basic-offset 4))) */