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   1 /*-------------------------------------------------------------------------
   2
   3   pcoderegs.c - post code generation register optimizations
   4
   5    Written By -  Scott Dattalo scott@dattalo.com
   6    Ported To PIC16 By -  m.dubuc@rogers.com
   7
   8    This program is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published by the
  10    Free Software Foundation; either version 2, or (at your option) any
  11    later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21
  22 -------------------------------------------------------------------------*/
  23
  24 /*
  25   pcoderegs.c
  26
  27   The purpose of the code in this file is to optimize the register usage.
  28
  29 */
  30 #include <stdio.h>
  31
  32 #include "common.h"   // Include everything in the SDCC src directory
  33 #include "newalloc.h"
  34 #include "ralloc.h"
  35 #include "device.h"
  36 #include "pcode.h"
  37 #include "pcoderegs.h"
  38 #include "pcodeflow.h"
  39
  40 extern void pic16_pCodeInsertAfter(pCode *pc1, pCode *pc2);
  41 extern pCode * pic16_findPrevInstruction(pCode *pci);
  42 extern pBranch * pic16_pBranchAppend(pBranch *h, pBranch *n);
  43 void pic16_unlinkpCode(pCode *pc);
  44 extern int pic16_pCodeSearchCondition(pCode *pc, unsigned int cond);
  45
  46 static int total_registers_saved=0;
  47 static int register_optimization=1;
  48
  49 /*-----------------------------------------------------------------*
  50  * void AddRegToFlow(regs *reg, pCodeFlow *pcfl)
  51  *-----------------------------------------------------------------*/
  52 /*
  53 void AddRegToFlow(regs *reg, pCodeFlow *pcfl)
  54 {
  55
  56   if(!reg || ! pcfl || !isPCFL(pcflow))
  57     return;
  58
  59   if(!pcfl->registers)
  60     pcfl->registers =  newSet();
  61
  62 }
  63 */
  64
  65
  66 /*-----------------------------------------------------------------*
  67  *
  68  *-----------------------------------------------------------------*/
  69 #if 0
  70 static void dbg_regusage(set *fregs)
  71 {
  72   regs *reg;
  73   pCode *pcfl;
  74   pCode *pc;
  75
  76
  77   for (reg = setFirstItem(fregs) ; reg ;
  78        reg = setNextItem(fregs)) {
  79
  80     if(elementsInSet(reg->reglives.usedpCodes)) {
  81
  82       fprintf (stderr, "%s  addr=0x%03x rIdx=0x%03x",
  83                reg->name,
  84                reg->address,
  85                reg->rIdx);
  86
  87       pcfl = setFirstItem(reg->reglives.usedpFlows);
  88       if(pcfl)
  89         fprintf(stderr, "\n   used in seq");
  90
  91       while(pcfl) {
  92         fprintf(stderr," 0x%03x",pcfl->seq);
  93         pcfl = setNextItem(reg->reglives.usedpFlows);
  94       }
  95
  96       pcfl = setFirstItem(reg->reglives.assignedpFlows);
  97       if(pcfl)
  98         fprintf(stderr, "\n   assigned in seq");
  99
 100       while(pcfl) {
 101         fprintf(stderr," 0x%03x",pcfl->seq);
 102         pcfl = setNextItem(reg->reglives.assignedpFlows);
 103       }
 104
 105       pc = setFirstItem(reg->reglives.usedpCodes);
 106       if(pc)
 107         fprintf(stderr, "\n   used in instructions ");
 108
 109       while(pc) {
 110         pcfl = PCODE(PCI(pc)->pcflow);
 111         if(pcfl)
 112           fprintf(stderr," 0x%03x:",pcfl->seq);
 113         fprintf(stderr,"0x%03x",pc->seq);
 114
 115         pc = setNextItem(reg->reglives.usedpCodes);
 116       }
 117
 118       fprintf(stderr, "\n");
 119     }
 120   }
 121 }
 122 #endif
 123
 124 /*-----------------------------------------------------------------*
 125  *
 126  *-----------------------------------------------------------------*/
 127 #if 0
 128 static void dbg_dumpregusage(void)
 129 {
 130
 131   fprintf(stderr,"***  Register Usage  ***\n");
 132   fprintf(stderr,"InternalRegs:\n");
 133   dbg_regusage(pic16_dynInternalRegs);
 134   fprintf(stderr,"AllocRegs:\n");
 135   dbg_regusage(pic16_dynAllocRegs);
 136   fprintf(stderr,"StackRegs:\n");
 137   dbg_regusage(pic16_dynStackRegs);
 138   fprintf(stderr,"DirectRegs:\n");
 139   dbg_regusage(pic16_dynDirectRegs);
 140   fprintf(stderr,"DirectBitRegs:\n");
 141   dbg_regusage(pic16_dynDirectBitRegs);
 142   fprintf(stderr,"ProcessorRegs:\n");
 143   dbg_regusage(pic16_dynProcessorRegs);
 144
 145 }
 146 #endif
 147
 148 /*-----------------------------------------------------------------*
 149  * void pCodeRegMapLiveRangesInFlow(pCodeFlow *pcfl)
 150  *-----------------------------------------------------------------*/
 151 static void pCodeRegMapLiveRangesInFlow(pCodeFlow *pcfl)
 152 {
 153
 154   pCode *pc=NULL;
 155   pCode *pcprev=NULL;
 156
 157   regs *reg;
 158
 159   if(!pcfl)
 160     return;
 161
 162
 163   pc = pic16_findNextInstruction(pcfl->pc.next);
 164
 165   while(pic16_isPCinFlow(pc,PCODE(pcfl))) {
 166
 167
 168     reg = pic16_getRegFromInstruction(pc);
 169
 170     if(reg) {
 171
 172 #if 0
 173       fprintf(stderr, "reg= %p\n", reg);
 174       fprintf(stderr, "flow seq %d, inst seq %d  %s  ",PCODE(pcfl)->seq,pc->seq,reg->name);
 175       fprintf(stderr, "addr = 0x%03x, type = %d  rIdx=0x%03x",
 176               reg->address,reg->type,reg->rIdx);
 177       fprintf(stderr, "command = %s\n", PCI(pc)->mnemonic);
 178
 179 #endif
 180
 181       addSetIfnotP(& (PCFL(pcfl)->registers), reg);
 182
 183       if((PCC_REGISTER | PCC_LITERAL) & PCI(pc)->inCond)
 184         addSetIfnotP(& (reg->reglives.usedpFlows), pcfl);
 185
 186       if(PCC_REGISTER & PCI(pc)->outCond)
 187         addSetIfnotP(& (reg->reglives.assignedpFlows), pcfl);
 188
 189       addSetIfnotP(& (reg->reglives.usedpCodes), pc);
 190
 191 #if 1
 192         /* check to see if this pCode has 2 memory operands,
 193            and set up the second operand too */
 194         if(PCI(pc)->is2MemOp) {
 195                         reg = pic16_getRegFromInstruction2(pc);
 196
 197 //                      fprintf(stderr, "trying to get second operand from pCode reg= %s\n", reg->name);
 198                         addSetIfnotP(& (PCFL(pcfl)->registers), reg);
 199
 200                         if((PCC_REGISTER | PCC_LITERAL) & PCI(pc)->inCond)
 201                                 addSetIfnotP(& (reg->reglives.usedpFlows), pcfl);
 202
 203                         if(PCC_REGISTER & PCI(pc)->outCond)
 204                                 addSetIfnotP(& (reg->reglives.assignedpFlows), pcfl);
 205
 206                         addSetIfnotP(& (reg->reglives.usedpCodes), pc);
 207
 208         }
 209 #endif
 210
 211     }
 212
 213
 214     pcprev = pc;
 215     pc = pic16_findNextInstruction(pc->next);
 216
 217   }
 218
 219 }
 220
 221 /*-----------------------------------------------------------------*
 222  * void pic16_pCodeRegMapLiveRanges(pBlock *pb)
 223  *-----------------------------------------------------------------*/
 224 void pic16_pCodeRegMapLiveRanges(pBlock *pb)
 225 {
 226   pCode *pcflow;
 227
 228   for( pcflow = pic16_findNextpCode(pb->pcHead, PC_FLOW);
 229        pcflow != NULL;
 230        pcflow = pic16_findNextpCode(pcflow->next, PC_FLOW) ) {
 231
 232     if(!isPCFL(pcflow)) {
 233       fprintf(stderr, "pCodeRegMapLiveRanges - pcflow is not a flow object ");
 234       continue;
 235     }
 236     pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 237   }
 238
 239 #if 0
 240   for( pcflow = pic16_findNextpCode(pb->pcHead, PC_FLOW);
 241        pcflow != NULL;
 242        pcflow = pic16_findNextpCode(pcflow->next, PC_FLOW) ) {
 243
 244     regs *r = setFirstItem(PCFL(pcflow)->registers);
 245     fprintf(stderr,"flow seq %d\n", pcflow->seq);
 246
 247     while (r) {
 248       fprintf(stderr, "  %s\n",r->name);
 249       r = setNextItem(PCFL(pcflow)->registers);
 250
 251     }
 252
 253   }
 254 #endif
 255
 256 //  dbg_dumpregusage();
 257
 258 }
 259
 260
 261 /*-----------------------------------------------------------------*
 262  *
 263  *-----------------------------------------------------------------*/
 264 static void Remove1pcode(pCode *pc, regs *reg)
 265 {
 266   pCode *pcn=NULL;
 267
 268   if(!reg || !pc)
 269     return;
 270
 271   deleteSetItem (&(reg->reglives.usedpCodes),pc);
 272
 273 #if 0
 274   fprintf(stderr,"removing instruction:\n");
 275   pc->print(stderr,pc);
 276 #endif
 277
 278   if(PCI(pc)->label) {
 279     pcn = pic16_findNextInstruction(pc->next);
 280
 281     if(pcn)
 282       PCI(pcn)->label = pic16_pBranchAppend(PCI(pcn)->label,PCI(pc)->label);
 283   }
 284
 285   if(PCI(pc)->cline) {
 286     if(!pcn)
 287       pcn = pic16_findNextInstruction(pc->next);
 288
 289     if(pcn) {
 290       if(PCI(pcn)->cline) {
 291         //fprintf(stderr, "source line has been optimized completely out\n");
 292         //pc->print(stderr,pc);
 293       } else {
 294         PCI(pcn)->cline = PCI(pc)->cline;
 295       }
 296     }
 297   }
 298
 299   pc->destruct(pc);
 300
 301 }
 302
 303 /*-----------------------------------------------------------------*
 304  * void RemoveRegsFromSet(set *regset)
 305  *
 306  *-----------------------------------------------------------------*/
 307 static void  RemoveRegsFromSet(set *regset)
 308 {
 309   regs *reg;
 310   int used;
 311
 312   while(regset) {
 313     reg = regset->item;
 314     regset = regset->next;
 315
 316     used = elementsInSet(reg->reglives.usedpCodes);
 317
 318     if(used <= 1) {
 319
 320 //      fprintf(stderr," reg %s isfree=%d, wasused=%d\n",reg->name,reg->isFree,reg->wasUsed);
 321       if(used == 0) {
 322 //              fprintf(stderr,"%s:%d: getting rid of reg %s\n",__FILE__, __LINE__, reg->name);
 323         reg->isFree = 1;
 324         reg->wasUsed = 0;
 325       } else {
 326         pCode *pc;
 327
 328
 329         pc = setFirstItem(reg->reglives.usedpCodes);
 330
 331         if(reg->type == REG_SFR) {
 332                 fprintf(stderr, "not removing SFR reg %s even though used only once\n",reg->name);
 333           continue;
 334         }
 335
 336
 337         if(isPCI(pc)) {
 338           if(PCI(pc)->label) {
 339             pCode *pcn = pic16_findNextInstruction(pc->next);
 340
 341             if(pcn && PCI(pcn)->label) {
 342               //fprintf(stderr,"can't delete instruction with label...\n");
 343               //pc->print(stderr,pc);
 344               continue;
 345             }
 346             /* Move the label to the next instruction */
 347
 348             PCI(pcn)->label = PCI(pc)->label;
 349
 350           }
 351
 352           if(isPCI_SKIP(pc)) {
 353             regs *r = pic16_getRegFromInstruction(pc);
 354             fprintf(stderr, "WARNING, a skip instruction is being optimized out\n");
 355             pc->print(stderr,pc);
 356             fprintf(stderr,"reg %s, type =%d\n",r->name, r->type);
 357           }
 358 //              fprintf(stderr,"%s:%d: removing reg %s because it is used only once\n",__FILE__, __LINE__, reg->name);
 359           Remove1pcode(pc, reg);
 360           /*
 361             pic16_unlinkpCode(pc);
 362             deleteSetItem (&(reg->reglives.usedpCodes),pc);
 363           */
 364           reg->isFree = 1;
 365           reg->wasUsed = 0;
 366           total_registers_saved++;  // debugging stats.
 367         }
 368       }
 369     }
 370
 371   }
 372 }
 373 /*-----------------------------------------------------------------*
 374  * void pic16_RemoveUnusedRegisters(void)
 375  *
 376  *-----------------------------------------------------------------*/
 377 void pic16_RemoveUnusedRegisters(void)
 378 {
 379   /* First, get rid of registers that are used only one time */
 380
 381   //RemoveRegsFromSet(pic16_dynInternalRegs);
 382   RemoveRegsFromSet(pic16_dynAllocRegs);
 383   RemoveRegsFromSet(pic16_dynStackRegs);
 384   /*
 385     don't do DirectRegs yet - there's a problem with arrays
 386   RemoveRegsFromSet(pic16_dynDirectRegs);
 387   */
 388   RemoveRegsFromSet(pic16_dynDirectBitRegs);
 389
 390   if(total_registers_saved) fprintf(stderr, " *** Saved %d registers ***\n", total_registers_saved);
 391 }
 392
 393
 394 /*-----------------------------------------------------------------*
 395  *
 396  *-----------------------------------------------------------------*/
 397 static void Remove2pcodes(pCode *pcflow, pCode *pc1, pCode *pc2, regs *reg, int can_free)
 398 {
 399   if(!reg)
 400     return;
 401
 402   if(pc1)
 403     Remove1pcode(pc1, reg);
 404
 405   if(pc2) {
 406     Remove1pcode(pc2, reg);
 407     deleteSetItem (&(PCFL(pcflow)->registers), reg);
 408
 409     if(can_free) {
 410       reg->isFree = 1;
 411       reg->wasUsed = 0;
 412     }
 413
 414   }
 415
 416   pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 417 }
 418
 419 /*-----------------------------------------------------------------*
 420  *
 421  *-----------------------------------------------------------------*/
 422 static int regUsedinRange(pCode *pc1, pCode *pc2, regs *reg)
 423 {
 424   int i=0;
 425   regs *testreg;
 426
 427   do {
 428     testreg = pic16_getRegFromInstruction(pc1);
 429     if(testreg && (testreg->rIdx == reg->rIdx)) {
 430       return 1;
 431     }
 432
 433     pc1 = pic16_findNextInstruction(pc1->next);
 434
 435   } while (pc1 && (pc1 != pc2) && (i++ < 100)) ;
 436
 437   if(i >= 100)
 438     fprintf(stderr, "warning, regUsedinRange searched through too many pcodes\n");
 439
 440   return 0;
 441 }
 442
 443 /*-----------------------------------------------------------------*
 444  * void pCodeOptime2pCodes(pCode *pc1, pCode *pc2)
 445  *
 446  * ADHOC pattern checking
 447  * Now look for specific sequences that are easy to optimize.
 448  * Many of these sequences are characteristic of the compiler
 449  * (i.e. it'd probably be a waste of time to apply these adhoc
 450  * checks to hand written assembly.)
 451  *
 452  *
 453  *-----------------------------------------------------------------*/
 454 static int pCodeOptime2pCodes(pCode *pc1, pCode *pc2, pCode *pcfl_used, regs *reg, int can_free, int optimize_level)
 455 {
 456   pCode *pct1, *pct2;
 457   regs  *reg1, *reg2;
 458
 459   int t = total_registers_saved;
 460
 461   if(pc2->seq < pc1->seq) {
 462     pct1 = pc2;
 463     pc2 = pc1;
 464     pc1 = pct1;
 465   }
 466 /*
 467   fprintf(stderr,"pCodeOptime2pCodes\n");
 468   pc1->print(stderr,pc1);
 469   pc2->print(stderr,pc2);
 470 */
 471   if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_MOVFW) ){
 472
 473     /*
 474       clrf  reg
 475       stuff...
 476       movf  reg,w
 477
 478       can be replaced with
 479
 480       stuff...
 481       movlw 0
 482     */
 483
 484     pCode *newpc;
 485     //fprintf(stderr, "   CLRF/MOVFW. instruction after MOVFW is:\n");
 486     pct1 = pic16_findNextInstruction(pc2->next);
 487
 488     if(PCI(pct1)->op == POC_MOVWF) {
 489       newpc = pic16_newpCode(POC_CLRF, PCI(pct1)->pcop);
 490       pct1->destruct(pct1);
 491     } else {
 492       newpc = pic16_newpCode(POC_MOVLW, pic16_newpCodeOpLit(0));
 493     }
 494
 495     pic16_pCodeInsertAfter(pc2, newpc);
 496     PCI(newpc)->pcflow = PCFL(pcfl_used);
 497     newpc->seq = pc2->seq;
 498
 499     Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 500     total_registers_saved++;  // debugging stats.
 501
 502   } else if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_IORFW) ){
 503     //fprintf(stderr, "   CLRF/IORFW.\n");
 504
 505     pct2 = pic16_findNextInstruction(pc2->next);
 506
 507     if(pic16_pCodeSearchCondition(pct2, PCC_Z) > 0) {
 508       pct2 = pic16_newpCode(POC_IORLW, pic16_newpCodeOpLit(0));
 509       pct2->seq = pc2->seq;
 510       PCI(pct2)->pcflow = PCFL(pcfl_used);
 511       pic16_pCodeInsertAfter(pc1,pct2);
 512     }
 513     Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 514     total_registers_saved++;  // debugging stats.
 515
 516   }  else if(PCI(pc1)->op == POC_MOVWF) {
 517
 518     pct2 = pic16_findNextInstruction(pc2->next);
 519
 520     if(PCI(pc2)->op == POC_MOVFW) {
 521       /*
 522         fprintf(stderr, "   MOVWF/MOVFW. instruction after MOVFW is:\n");
 523         pct2->print(stderr,pct2);
 524       */
 525
 526       if(PCI(pct2)->op == POC_MOVWF) {
 527         /*
 528           Change:
 529
 530             movwf   reg
 531
 532             stuff...
 533
 534             movf    reg,w
 535             movwf   reg2
 536
 537           To:
 538
 539
 540         */
 541         reg2 = pic16_getRegFromInstruction(pct2);
 542         //if(reg2 && !regUsedinRange(pc1,pc2,reg2) && (reg2->type != REG_SFR)) {
 543         if(reg2 && !regUsedinRange(pc1,pc2,reg2)) {
 544
 545           if(pic16_pCodeSearchCondition(pct2, PCC_Z) < 1) {
 546             pCode *pct3 = pic16_findNextInstruction(pct2->next);
 547             pct2->seq = pc1->seq;
 548             pic16_unlinkpCode(pct2);
 549             pic16_pCodeInsertAfter(pic16_findPrevInstruction(pc1->prev),pct2);
 550
 551 #define usesW(x)       ((x) && (isPCI(x)) && ( (PCI(x)->inCond & PCC_W) != 0))
 552
 553             if(usesW(pct3))
 554               ; // Remove2pcodes(pcfl_used, pc1, NULL, reg, can_free);
 555             else
 556               Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 557
 558             total_registers_saved++;  // debugging stats.
 559             return 1;
 560             } else {
 561               //fprintf(stderr,"didn't optimize because Z bit is used\n");
 562             }
 563         }
 564 /*
 565         fprintf(stderr, " couldn't optimize\n");
 566         if(reg2)
 567           fprintf(stderr, " %s is used in range\n",reg2->name);
 568         else
 569           fprintf(stderr, " reg2 is NULL\n");
 570 */
 571       }
 572     }
 573
 574     pct1 = pic16_findPrevInstruction(pc1->prev);
 575     if(pct1 && (PCI(pct1)->pcflow == PCI(pc1)->pcflow)) {
 576
 577       if ( (PCI(pct1)->op == POC_MOVFW) &&
 578            (PCI(pc2)->op == POC_MOVFW)) {
 579
 580         reg1 = pic16_getRegFromInstruction(pct1);
 581         if(reg1 && !regUsedinRange(pc1,pc2,reg1)) {
 582           /*
 583             fprintf(stderr, "   MOVF/MOVFW. \n");
 584             fprintf(stderr, "     ...optimizing\n");
 585           */
 586
 587           /*
 588             Change:
 589
 590             movf   reg1,w
 591             movwf  reg
 592
 593             stuff...
 594             movf   reg,w
 595
 596             To:
 597
 598             stuff...
 599
 600             movf   reg1,w
 601
 602             Or, if we're not deleting the register then the "To" is:
 603
 604             stuff...
 605
 606             movf   reg1,w
 607             movwf  reg
 608
 609
 610           */
 611           pct2 = pic16_newpCode(PCI(pc2)->op, PCI(pct1)->pcop);
 612           pic16_pCodeInsertAfter(pc2, pct2);
 613           PCI(pct2)->pcflow = PCFL(pcfl_used);
 614           pct2->seq = pc2->seq;
 615
 616           if(can_free) {
 617             Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 618           } else {
 619             /* If we're not freeing the register then that means (probably)
 620              * the register is needed somewhere else.*/
 621             pic16_unlinkpCode(pc1);
 622             pic16_pCodeInsertAfter(pct2, pc1);
 623
 624             Remove2pcodes(pcfl_used, pc2, NULL, reg, can_free);
 625           }
 626
 627           Remove2pcodes(pcfl_used, pct1, NULL, reg1, 0);
 628           total_registers_saved++;  // debugging stats.
 629
 630         }
 631       } else if ( (PCI(pct1)->op == POC_MOVWF) &&
 632            (PCI(pc2)->op == POC_MOVFW)) {
 633         //fprintf(stderr,"movwf MOVWF/MOVFW\n");
 634         if(optimize_level > 1 && can_free) {
 635           pct2 = pic16_newpCode(POC_MOVFW, PCI(pc1)->pcop);
 636           pic16_pCodeInsertAfter(pc2, pct2);
 637           Remove2pcodes(pcfl_used, pc1, pc2, reg, 1);
 638           total_registers_saved++;  // debugging stats.
 639         }
 640       }
 641
 642
 643     }
 644
 645   }
 646
 647   return (total_registers_saved != t);
 648 }
 649
 650 /*-----------------------------------------------------------------*
 651  * void pCodeRegOptimeRegUsage(pBlock *pb)
 652  *-----------------------------------------------------------------*/
 653 static void OptimizeRegUsage(set *fregs, int optimize_multi_uses, int optimize_level)
 654 {
 655   regs *reg;
 656   int used;
 657   pCode *pc1=NULL, *pc2=NULL;
 658
 659
 660   while(fregs) {
 661     pCode *pcfl_used, *pcfl_assigned;
 662
 663     /* Step through the set by directly accessing the 'next' pointer.
 664      * We could also step through by using the set API, but the
 665      * the (debug) calls to print instructions affect the state
 666      * of the set pointers */
 667
 668     reg = fregs->item;
 669     fregs = fregs->next;
 670
 671         if(reg->type == REG_SFR) {
 672 //              fprintf(stderr,"skipping SFR: %s\n",reg->name);
 673                 continue;
 674         }
 675
 676     pcfl_used = setFirstItem(reg->reglives.usedpFlows);
 677     pcfl_assigned = setFirstItem(reg->reglives.assignedpFlows);
 678
 679     used = elementsInSet(reg->reglives.usedpCodes);
 680 //      fprintf(stderr, "%s:%d register %s used %d times in pCode\n", __FILE__, __LINE__, reg->name, used);
 681     if(used == 2) {
 682
 683       /*
 684        * In this section, all registers that are used in only in two
 685        * instructions are examined. If possible, they're optimized out.
 686        */
 687
 688 #if 0
 689       fprintf (stderr, "OptimizeRegUsage: %s  addr=0x%03x rIdx=0x%03x type=%d used=%d\n",
 690                reg->name,
 691                reg->address,
 692                reg->rIdx, reg->type, used);
 693 #endif
 694
 695       pc1 = setFirstItem(reg->reglives.usedpCodes);
 696       pc2 = setNextItem(reg->reglives.usedpCodes);
 697
 698       if(pcfl_used && pcfl_assigned) {
 699
 700         /*
 701            expected case - the register has been assigned a value and is
 702            subsequently used
 703         */
 704
 705         //fprintf(stderr," used only twice\n");
 706         if(pcfl_used->seq == pcfl_assigned->seq) {
 707
 708           //fprintf(stderr, "  and used in same flow\n");
 709
 710           pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 1,optimize_level);
 711
 712         } else {
 713           // fprintf(stderr, "  and used in different flows\n");
 714
 715         }
 716
 717       } else if(pcfl_used) {
 718
 719         /*
 720           register has been used twice without ever being assigned */
 721         //fprintf(stderr,"WARNING %s: reg %s used without being assigned\n",__FUNCTION__,reg->name);
 722
 723       } else {
 724 //              fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 725         Remove2pcodes(pcfl_assigned, pc1, pc2, reg, 1);
 726         total_registers_saved++;  // debugging stats.
 727       }
 728     } else {
 729
 730       /* register has been used either once, or more than twice */
 731
 732       if(used && !pcfl_used && pcfl_assigned) {
 733         pCode *pc;
 734
 735 //              fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 736
 737         pc = setFirstItem(reg->reglives.usedpCodes);
 738         while(pc) {
 739
 740           pcfl_assigned = PCODE(PCI(pc)->pcflow);
 741           Remove1pcode(pc, reg);
 742
 743           deleteSetItem (&(PCFL(pcfl_assigned)->registers), reg);
 744           /*
 745           deleteSetItem (&(reg->reglives.usedpCodes),pc);
 746           pc->destruct(pc);
 747           */
 748           pc = setNextItem(reg->reglives.usedpCodes);
 749         }
 750
 751
 752         reg->isFree = 1;
 753         reg->wasUsed = 0;
 754
 755         total_registers_saved++;  // debugging stats.
 756       } else if( (used > 2) && optimize_multi_uses) {
 757
 758         set *rset1=NULL;
 759         set *rset2=NULL;
 760         int searching=1;
 761
 762         pCodeFlow *pcfl1=NULL, *pcfl2=NULL;
 763
 764         /* examine the number of times this register is used */
 765
 766
 767         rset1 = reg->reglives.usedpCodes;
 768         while(rset1 && searching) {
 769
 770           pc1 = rset1->item;
 771           rset2 = rset1->next;
 772
 773           if(pc1 && isPCI(pc1) &&  ( (pcfl1 = PCI(pc1)->pcflow) != NULL) ) {
 774
 775             //while(rset2 && searching) {
 776             if(rset2) {
 777
 778               pc2 = rset2->item;
 779               if(pc2 && isPCI(pc2)  &&  ( (pcfl2 = PCI(pc2)->pcflow) != NULL) )  {
 780                 if(pcfl2 == pcfl1) {
 781
 782                   if(pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 0,optimize_level))
 783                     searching = 0;
 784                 }
 785               }
 786
 787               //rset2 = rset2->next;
 788
 789             }
 790           }
 791           rset1 = rset1->next;
 792         }
 793       }
 794     }
 795
 796   }
 797
 798 }
 799 /*-----------------------------------------------------------------*
 800  * void pic16_pCodeRegOptimeRegUsage(pBlock *pb)
 801  *-----------------------------------------------------------------*/
 802 void pic16_pCodeRegOptimizeRegUsage(int level)
 803 {
 804
 805   int passes;
 806   int saved = 0;
 807   int t = total_registers_saved;
 808
 809   if(!register_optimization)
 810     return;
 811 #define OPT_PASSES 4
 812   passes = OPT_PASSES;
 813
 814   do {
 815     saved = total_registers_saved;
 816
 817     /* Identify registers used in one flow sequence */
 818     OptimizeRegUsage(pic16_dynAllocRegs,level, (OPT_PASSES-passes));
 819     OptimizeRegUsage(pic16_dynStackRegs,level, (OPT_PASSES-passes));
 820     OptimizeRegUsage(pic16_dynDirectRegs,0, (OPT_PASSES-passes));
 821
 822     if(total_registers_saved != saved)
 823       fprintf(stderr, " *** pass %d, Saved %d registers, total saved %d ***\n",
 824               (1+OPT_PASSES-passes),total_registers_saved-saved,total_registers_saved);
 825
 826     passes--;
 827
 828   } while( passes && ((total_registers_saved != saved) || (passes==OPT_PASSES-1)) );
 829
 830   if(total_registers_saved == t)
 831
 832   if(pic16_debug_verbose)
 833     fprintf(stderr, "No registers saved on this pass\n");
 834
 835
 836 /*
 837   fprintf(stderr,"dynamically allocated regs:\n");
 838   dbg_regusage(pic16_dynAllocRegs);
 839   fprintf(stderr,"stack regs:\n");
 840   dbg_regusage(pic16_dynStackRegs);
 841   fprintf(stderr,"direct regs:\n");
 842   dbg_regusage(pic16_dynDirectRegs);
 843 */
 844 }
 845
 846
 847 /*-----------------------------------------------------------------*
 848  * void RegsUnMapLiveRanges(set *regset)
 849  *
 850  *-----------------------------------------------------------------*/
 851 static void  RegsSetUnMapLiveRanges(set *regset)
 852 {
 853   regs *reg;
 854
 855   while(regset) {
 856     reg = regset->item;
 857     regset = regset->next;
 858
 859
 860     deleteSet(&reg->reglives.usedpCodes);
 861     deleteSet(&reg->reglives.usedpFlows);
 862     deleteSet(&reg->reglives.assignedpFlows);
 863
 864   }
 865
 866 }
 867
 868 void  pic16_RegsUnMapLiveRanges(void)
 869 {
 870
 871   RegsSetUnMapLiveRanges(pic16_dynAllocRegs);
 872   RegsSetUnMapLiveRanges(pic16_dynStackRegs);
 873   RegsSetUnMapLiveRanges(pic16_dynDirectRegs);
 874   RegsSetUnMapLiveRanges(pic16_dynProcessorRegs);
 875   RegsSetUnMapLiveRanges(pic16_dynDirectBitRegs);
 876   RegsSetUnMapLiveRanges(pic16_dynInternalRegs);
 877
 878 }