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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 && (reg->type != REG_TMP)) {
 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 //      fprintf(stderr, "%s:%d: trying to get first operand from pCode reg= %s\n", __FILE__, __LINE__, reg->name);
 182       addSetIfnotP(& (PCFL(pcfl)->registers), reg);
 183
 184       if((PCC_REGISTER | PCC_LITERAL) & PCI(pc)->inCond)
 185         addSetIfnotP(& (reg->reglives.usedpFlows), pcfl);
 186
 187       if(PCC_REGISTER & PCI(pc)->outCond)
 188         addSetIfnotP(& (reg->reglives.assignedpFlows), pcfl);
 189
 190       addSetIfnotP(& (reg->reglives.usedpCodes), pc);
 191
 192 #if 1
 193         /* check to see if this pCode has 2 memory operands,
 194            and set up the second operand too */
 195         if(PCI(pc)->is2MemOp) {
 196                         reg = pic16_getRegFromInstruction2(pc);
 197                         if(reg) {
 198 //                              fprintf(stderr, "%s:%d: trying to get second operand from pCode reg= %s\n", __FILE__, __LINE__, reg->name);
 199                                 addSetIfnotP(& (PCFL(pcfl)->registers), reg);
 200
 201                                 if((PCC_REGISTER | PCC_LITERAL) & PCI(pc)->inCond)
 202                                         addSetIfnotP(& (reg->reglives.usedpFlows), pcfl);
 203
 204                                 if((PCC_REGISTER | PCC_REGISTER2) & PCI(pc)->outCond)
 205                                         addSetIfnotP(& (reg->reglives.assignedpFlows), pcfl);
 206
 207                                 addSetIfnotP(& (reg->reglives.usedpCodes), pc);
 208                         }
 209         }
 210 #endif
 211
 212     }
 213
 214
 215     pcprev = pc;
 216     pc = pic16_findNextInstruction(pc->next);
 217
 218   }
 219
 220 }
 221
 222 /*-----------------------------------------------------------------*
 223  * void pic16_pCodeRegMapLiveRanges(pBlock *pb)
 224  *-----------------------------------------------------------------*/
 225 void pic16_pCodeRegMapLiveRanges(pBlock *pb)
 226 {
 227   pCode *pcflow;
 228
 229   for( pcflow = pic16_findNextpCode(pb->pcHead, PC_FLOW);
 230        pcflow != NULL;
 231        pcflow = pic16_findNextpCode(pcflow->next, PC_FLOW) ) {
 232
 233     if(!isPCFL(pcflow)) {
 234       fprintf(stderr, "pCodeRegMapLiveRanges - pcflow is not a flow object ");
 235       continue;
 236     }
 237     pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 238   }
 239
 240 #if 0
 241   for( pcflow = pic16_findNextpCode(pb->pcHead, PC_FLOW);
 242        pcflow != NULL;
 243        pcflow = pic16_findNextpCode(pcflow->next, PC_FLOW) ) {
 244
 245     regs *r = setFirstItem(PCFL(pcflow)->registers);
 246     fprintf(stderr,"flow seq %d\n", pcflow->seq);
 247
 248     while (r) {
 249       fprintf(stderr, "  %s\n",r->name);
 250       r = setNextItem(PCFL(pcflow)->registers);
 251
 252     }
 253
 254   }
 255 #endif
 256
 257 //  dbg_dumpregusage();
 258
 259 }
 260
 261
 262 /*-----------------------------------------------------------------*
 263  *
 264  *-----------------------------------------------------------------*/
 265 static void Remove1pcode(pCode *pc, regs *reg)
 266 {
 267   pCode *pcn=NULL;
 268
 269   if(!reg || !pc)
 270     return;
 271
 272   deleteSetItem (&(reg->reglives.usedpCodes),pc);
 273
 274 #if 0
 275   fprintf(stderr,"removing instruction:\n");
 276   pc->print(stderr,pc);
 277 #endif
 278
 279   if(PCI(pc)->label) {
 280     pcn = pic16_findNextInstruction(pc->next);
 281
 282     if(pcn)
 283       PCI(pcn)->label = pic16_pBranchAppend(PCI(pcn)->label,PCI(pc)->label);
 284   }
 285
 286   if(PCI(pc)->cline) {
 287     if(!pcn)
 288       pcn = pic16_findNextInstruction(pc->next);
 289
 290     if(pcn) {
 291       if(PCI(pcn)->cline) {
 292         //fprintf(stderr, "source line has been optimized completely out\n");
 293         //pc->print(stderr,pc);
 294       } else {
 295         PCI(pcn)->cline = PCI(pc)->cline;
 296       }
 297     }
 298   }
 299
 300   pc->destruct(pc);
 301
 302 }
 303
 304 /*-----------------------------------------------------------------*
 305  * void RemoveRegsFromSet(set *regset)
 306  *
 307  *-----------------------------------------------------------------*/
 308 static void  RemoveRegsFromSet(set *regset)
 309 {
 310   regs *reg;
 311   int used;
 312
 313   while(regset) {
 314     reg = regset->item;
 315     regset = regset->next;
 316
 317     used = elementsInSet(reg->reglives.usedpCodes);
 318
 319     if(used <= 1) {
 320
 321 //      fprintf(stderr," reg %s isfree=%d, wasused=%d\n",reg->name,reg->isFree,reg->wasUsed);
 322
 323       if(used == 0) {
 324
 325 //      fprintf(stderr,"%s:%d: getting rid of reg %s\n",__FILE__, __LINE__, reg->name);
 326
 327         reg->isFree = 1;
 328         reg->wasUsed = 0;
 329       } else {
 330         pCode *pc;
 331
 332
 333         pc = setFirstItem(reg->reglives.usedpCodes);
 334
 335         if(reg->type == REG_SFR) {
 336                 fprintf(stderr, "not removing SFR reg %s even though used only once\n", reg->name);
 337           continue;
 338         }
 339
 340         if(isPCI(pc)) {
 341           if(PCI(pc)->label) {
 342             pCode *pcn = pic16_findNextInstruction(pc->next);
 343
 344             if(pcn && PCI(pcn)->label) {
 345               //fprintf(stderr,"can't delete instruction with label...\n");
 346               //pc->print(stderr,pc);
 347               continue;
 348             }
 349             /* Move the label to the next instruction */
 350
 351             PCI(pcn)->label = PCI(pc)->label;
 352
 353           }
 354
 355           if(isPCI_SKIP(pc)) {
 356             regs *r = pic16_getRegFromInstruction(pc);
 357             fprintf(stderr, "WARNING, a skip instruction is being optimized out\n");
 358             pc->print(stderr,pc);
 359             fprintf(stderr,"reg %s, type =%d\n",r->name, r->type);
 360           }
 361
 362
 363           pc->print(stderr, pc);
 364
 365           fprintf(stderr,"%s:%d: removing reg %s because it is used only once\n",__FILE__, __LINE__, reg->name);
 366
 367
 368           Remove1pcode(pc, reg);
 369           /*
 370             pic16_unlinkpCode(pc);
 371             deleteSetItem (&(reg->reglives.usedpCodes),pc);
 372           */
 373           reg->isFree = 1;
 374           reg->wasUsed = 0;
 375           total_registers_saved++;  // debugging stats.
 376         }
 377       }
 378     }
 379
 380   }
 381 }
 382 /*-----------------------------------------------------------------*
 383  * void pic16_RemoveUnusedRegisters(void)
 384  *
 385  *-----------------------------------------------------------------*/
 386 void pic16_RemoveUnusedRegisters(void)
 387 {
 388   /* First, get rid of registers that are used only one time */
 389
 390   //RemoveRegsFromSet(pic16_dynInternalRegs);
 391   RemoveRegsFromSet(pic16_dynAllocRegs);
 392   RemoveRegsFromSet(pic16_dynStackRegs);
 393   /*
 394     don't do DirectRegs yet - there's a problem with arrays
 395   RemoveRegsFromSet(pic16_dynDirectRegs);
 396   */
 397   RemoveRegsFromSet(pic16_dynDirectBitRegs);
 398
 399   if(total_registers_saved && pic16_pcode_verbose)
 400         fprintf(stderr, " *** Saved %d registers ***\n", total_registers_saved);
 401 }
 402
 403
 404 /*-----------------------------------------------------------------*
 405  *
 406  *-----------------------------------------------------------------*/
 407 static void Remove2pcodes(pCode *pcflow, pCode *pc1, pCode *pc2, regs *reg, int can_free)
 408 {
 409   if(!reg)
 410     return;
 411
 412 #if 0
 413   fprintf(stderr,"removing 2 instructions:\n");
 414   pc1->print(stderr,pc1);
 415   pc2->print(stderr,pc2);
 416 #endif
 417
 418   if(pc1)
 419     Remove1pcode(pc1, reg);
 420
 421   if(pc2) {
 422     Remove1pcode(pc2, reg);
 423     deleteSetItem (&(PCFL(pcflow)->registers), reg);
 424
 425     if(can_free) {
 426       reg->isFree = 1;
 427       reg->wasUsed = 0;
 428     }
 429
 430   }
 431
 432   pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 433 }
 434
 435 /*-----------------------------------------------------------------*
 436  *
 437  *-----------------------------------------------------------------*/
 438 static int regUsedinRange(pCode *pc1, pCode *pc2, regs *reg)
 439 {
 440   int i=0;
 441   regs *testreg;
 442
 443   do {
 444     testreg = pic16_getRegFromInstruction(pc1);
 445     if(testreg && (testreg->rIdx == reg->rIdx)) {
 446       return 1;
 447     }
 448
 449     pc1 = pic16_findNextInstruction(pc1->next);
 450
 451   } while (pc1 && (pc1 != pc2) && (i++ < 100)) ;
 452
 453   if(i >= 100)
 454     fprintf(stderr, "warning, regUsedinRange searched through too many pcodes\n");
 455
 456   return 0;
 457 }
 458
 459 /*-----------------------------------------------------------------*
 460  * void pCodeOptime2pCodes(pCode *pc1, pCode *pc2)
 461  *
 462  * ADHOC pattern checking
 463  * Now look for specific sequences that are easy to optimize.
 464  * Many of these sequences are characteristic of the compiler
 465  * (i.e. it'd probably be a waste of time to apply these adhoc
 466  * checks to hand written assembly.)
 467  *
 468  *
 469  *-----------------------------------------------------------------*/
 470 static int pCodeOptime2pCodes(pCode *pc1, pCode *pc2, pCode *pcfl_used, regs *reg, int can_free, int optimize_level)
 471 {
 472   pCode *pct1, *pct2;
 473   regs  *reg1, *reg2;
 474
 475   int t = total_registers_saved;
 476
 477   if(reg->type == REG_SFR)return 0;
 478
 479   if(pc2->seq < pc1->seq) {
 480     pct1 = pc2;
 481     pc2 = pc1;
 482     pc1 = pct1;
 483   }
 484 /*
 485   fprintf(stderr,"pCodeOptime2pCodes\n");
 486   pc1->print(stderr,pc1);
 487   pc2->print(stderr,pc2);
 488 */
 489   if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_MOVFW) ){
 490
 491     /*
 492       clrf  reg
 493       stuff...
 494       movf  reg,w
 495
 496       can be replaced with
 497
 498       stuff...
 499       movlw 0
 500     */
 501
 502     pCode *newpc;
 503     //fprintf(stderr, "   CLRF/MOVFW. instruction after MOVFW is:\n");
 504     pct1 = pic16_findNextInstruction(pc2->next);
 505
 506     if(PCI(pct1)->op == POC_MOVWF) {
 507       newpc = pic16_newpCode(POC_CLRF, PCI(pct1)->pcop);
 508       pct1->destruct(pct1);
 509     } else {
 510       newpc = pic16_newpCode(POC_MOVLW, pic16_newpCodeOpLit(0));
 511     }
 512
 513     pic16_pCodeInsertAfter(pc2, newpc);
 514     PCI(newpc)->pcflow = PCFL(pcfl_used);
 515     newpc->seq = pc2->seq;
 516
 517     /* take care if register is used after pc2, if yes, then don't delete
 518      * clrf reg, because, reg should be initialized with zero */
 519     {
 520       pCode *spc;
 521       int maxSeq=0;
 522
 523         for(spc=setFirstItem(reg->reglives.usedpCodes);spc;spc=setNextItem(reg->reglives.usedpCodes)) {
 524           if(maxSeq < spc->seq)maxSeq = spc->seq;
 525         }
 526
 527 //        fprintf(stderr, "pc1->seq = %d\tpc2->seq = %d\tspc->seq = %d\n", pc1->seq, pc2->seq, maxSeq);
 528
 529         if(maxSeq > pc2->seq) {
 530           /* this means that a pCode uses register after pc2, then
 531            * we can't delete pc1 pCode */
 532           Remove2pcodes(pcfl_used, NULL, pc2, reg, can_free);
 533         } else {
 534           /* we can remove both pCodes */
 535           Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 536         }
 537     }
 538     total_registers_saved++;  // debugging stats.
 539
 540   } else if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_IORFW) ){
 541     //fprintf(stderr, "   CLRF/IORFW.\n");
 542
 543     pct2 = pic16_findNextInstruction(pc2->next);
 544
 545     if(pic16_pCodeSearchCondition(pct2, PCC_Z) > 0) {
 546       pct2 = pic16_newpCode(POC_IORLW, pic16_newpCodeOpLit(0));
 547       pct2->seq = pc2->seq;
 548       PCI(pct2)->pcflow = PCFL(pcfl_used);
 549       pic16_pCodeInsertAfter(pc1,pct2);
 550     }
 551     Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 552     total_registers_saved++;  // debugging stats.
 553
 554   }  else if(PCI(pc1)->op == POC_MOVWF) {
 555
 556     reg1 = pic16_getRegFromInstruction(pc1);
 557
 558     if(reg1->type == REG_SFR)return (total_registers_saved != t);
 559
 560     pct2 = pic16_findNextInstruction(pc2->next);
 561
 562     if(PCI(pc2)->op == POC_MOVFW) {
 563
 564 #if 0
 565         fprintf(stderr, "   MOVWF/MOVFW. instruction after MOVFW is:\n");
 566         pct2->print(stderr,pct2);
 567 #endif
 568
 569       if(PCI(pct2)->op == POC_MOVWF) {
 570         /*
 571           Change:
 572
 573             movwf   reg
 574
 575             stuff...
 576
 577             movf    reg,w
 578             movwf   reg2
 579
 580           To:
 581
 582
 583         */
 584         reg2 = pic16_getRegFromInstruction(pct2);
 585         if(reg2 && !regUsedinRange(pc1,pc2,reg2) && (reg2->type != REG_SFR)) {
 586 //      if(reg2 && !regUsedinRange(pc1,pc2,reg2))
 587
 588           if(pic16_pCodeSearchCondition(pct2, PCC_Z) < 1) {
 589             pCode *pct3 = pic16_findNextInstruction(pct2->next);
 590             pct2->seq = pc1->seq;
 591             pic16_unlinkpCode(pct2);
 592             pic16_pCodeInsertAfter(pic16_findPrevInstruction(pc1->prev),pct2);
 593
 594 #define usesW(x)       ((x) && (isPCI(x)) && ( (PCI(x)->inCond & PCC_W) != 0))
 595
 596             if(usesW(pct3))
 597               ; // Remove2pcodes(pcfl_used, pc1, NULL, reg, can_free);
 598             else
 599               Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 600
 601             total_registers_saved++;  // debugging stats.
 602             return 1;
 603             } else {
 604               //fprintf(stderr,"didn't optimize because Z bit is used\n");
 605             }
 606         }
 607 #if 0
 608         fprintf(stderr, " couldn't optimize\n");
 609         if(reg2)
 610           fprintf(stderr, " %s is used in range\n",reg2->name);
 611         else
 612           fprintf(stderr, " reg2 is NULL\n");
 613 #endif
 614       }
 615     }
 616
 617     pct1 = pic16_findPrevInstruction(pc1->prev);
 618     if(pct1 && (PCI(pct1)->pcflow == PCI(pc1)->pcflow)) {
 619
 620       if ( (PCI(pct1)->op == POC_MOVFW) &&
 621            (PCI(pc2)->op == POC_MOVFW)) {
 622
 623         reg1 = pic16_getRegFromInstruction(pct1);
 624         if(reg1 && !regUsedinRange(pc1,pc2,reg1)) {
 625           /*
 626             fprintf(stderr, "   MOVF/MOVFW. \n");
 627             fprintf(stderr, "     ...optimizing\n");
 628           */
 629
 630           /*
 631             Change:
 632
 633             movf   reg1,w
 634             movwf  reg
 635
 636             stuff...
 637             movf   reg,w
 638
 639             To:
 640
 641             stuff...
 642
 643             movf   reg1,w
 644
 645             Or, if we're not deleting the register then the "To" is:
 646
 647             stuff...
 648
 649             movf   reg1,w
 650             movwf  reg
 651
 652
 653           */
 654           pct2 = pic16_newpCode(PCI(pc2)->op, PCI(pct1)->pcop);
 655           pic16_pCodeInsertAfter(pc2, pct2);
 656           PCI(pct2)->pcflow = PCFL(pcfl_used);
 657           pct2->seq = pc2->seq;
 658
 659           if(can_free) {
 660             Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 661           } else {
 662             /* If we're not freeing the register then that means (probably)
 663              * the register is needed somewhere else.*/
 664             pic16_unlinkpCode(pc1);
 665             pic16_pCodeInsertAfter(pct2, pc1);
 666
 667             Remove2pcodes(pcfl_used, pc2, NULL, reg, can_free);
 668           }
 669
 670           Remove2pcodes(pcfl_used, pct1, NULL, reg1, 0);
 671           total_registers_saved++;  // debugging stats.
 672
 673         }
 674       } else if ( (PCI(pct1)->op == POC_MOVWF) &&
 675            (PCI(pc2)->op == POC_MOVFW)) {
 676
 677 //         fprintf(stderr,"movwf MOVWF/MOVFW\n");
 678
 679         if(optimize_level > 1 && can_free) {
 680           pct2 = pic16_newpCode(POC_MOVFW, PCI(pc1)->pcop);
 681           pic16_pCodeInsertAfter(pc2, pct2);
 682           Remove2pcodes(pcfl_used, pc1, pc2, reg, 1);
 683           total_registers_saved++;  // debugging stats.
 684         }
 685       }
 686
 687
 688     }
 689
 690   }
 691
 692   return (total_registers_saved != t);
 693 }
 694
 695 /*-----------------------------------------------------------------*
 696  * void pCodeRegOptimeRegUsage(pBlock *pb)
 697  *-----------------------------------------------------------------*/
 698 static void OptimizeRegUsage(set *fregs, int optimize_multi_uses, int optimize_level)
 699 {
 700   regs *reg;
 701   int used;
 702   pCode *pc1=NULL, *pc2=NULL;
 703
 704
 705   while(fregs) {
 706     pCode *pcfl_used, *pcfl_assigned;
 707
 708     /* Step through the set by directly accessing the 'next' pointer.
 709      * We could also step through by using the set API, but the
 710      * the (debug) calls to print instructions affect the state
 711      * of the set pointers */
 712
 713     reg = fregs->item;
 714     fregs = fregs->next;
 715
 716         if(reg->type == REG_SFR) {
 717 //              fprintf(stderr,"skipping SFR: %s\n",reg->name);
 718                 continue;
 719         }
 720
 721     pcfl_used = setFirstItem(reg->reglives.usedpFlows);
 722     pcfl_assigned = setFirstItem(reg->reglives.assignedpFlows);
 723
 724     used = elementsInSet(reg->reglives.usedpCodes);
 725 //      fprintf(stderr, "%s:%d register %s used %d times in pCode\n", __FILE__, __LINE__, reg->name, used);
 726     if(used == 2) {
 727
 728       /*
 729        * In this section, all registers that are used in only in two
 730        * instructions are examined. If possible, they're optimized out.
 731        */
 732
 733 #if 0
 734       fprintf (stderr, "OptimizeRegUsage: %s  addr=0x%03x rIdx=0x%03x type=%d used=%d\n",
 735                reg->name,
 736                reg->address,
 737                reg->rIdx, reg->type, used);
 738 #endif
 739
 740       pc1 = setFirstItem(reg->reglives.usedpCodes);
 741       pc2 = setNextItem(reg->reglives.usedpCodes);
 742
 743       if(pcfl_used && pcfl_assigned) {
 744
 745         /*
 746            expected case - the register has been assigned a value and is
 747            subsequently used
 748         */
 749
 750         //fprintf(stderr," used only twice\n");
 751         if(pcfl_used->seq == pcfl_assigned->seq && !(setNextItem(reg->reglives.usedpFlows)) && !(setNextItem(reg->reglives.assignedpFlows))) {
 752
 753           //fprintf(stderr, "  and used in same flow\n");
 754
 755           pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 1,optimize_level);
 756
 757         } else {
 758           // fprintf(stderr, "  and used in different flows\n");
 759
 760         }
 761
 762       } else if(pcfl_used) {
 763
 764         /*
 765           register has been used twice without ever being assigned */
 766         //fprintf(stderr,"WARNING %s: reg %s used without being assigned\n",__FUNCTION__,reg->name);
 767
 768       } else {
 769 //              fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 770         Remove2pcodes(pcfl_assigned, pc1, pc2, reg, 1);
 771         total_registers_saved++;  // debugging stats.
 772       }
 773     } else {
 774
 775       /* register has been used either once, or more than twice */
 776
 777       if(used && !pcfl_used && pcfl_assigned) {
 778         pCode *pc;
 779
 780                 fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 781
 782         pc = setFirstItem(reg->reglives.usedpCodes);
 783         while(pc) {
 784
 785           pcfl_assigned = PCODE(PCI(pc)->pcflow);
 786           Remove1pcode(pc, reg);
 787
 788           deleteSetItem (&(PCFL(pcfl_assigned)->registers), reg);
 789           /*
 790           deleteSetItem (&(reg->reglives.usedpCodes),pc);
 791           pc->destruct(pc);
 792           */
 793           pc = setNextItem(reg->reglives.usedpCodes);
 794         }
 795
 796
 797         reg->isFree = 1;
 798         reg->wasUsed = 0;
 799
 800         total_registers_saved++;  // debugging stats.
 801       } else if( (used > 2) && optimize_multi_uses) {
 802
 803         set *rset1=NULL;
 804         set *rset2=NULL;
 805         int searching=1;
 806
 807         pCodeFlow *pcfl1=NULL, *pcfl2=NULL;
 808
 809         /* examine the number of times this register is used */
 810
 811
 812         rset1 = reg->reglives.usedpCodes;
 813         while(rset1 && searching) {
 814
 815           pc1 = rset1->item;
 816           rset2 = rset1->next;
 817
 818           if(pc1 && isPCI(pc1) &&  ( (pcfl1 = PCI(pc1)->pcflow) != NULL) ) {
 819
 820             //while(rset2 && searching) {
 821             if(rset2) {
 822
 823               pc2 = rset2->item;
 824               if(pc2 && isPCI(pc2)  &&  ( (pcfl2 = PCI(pc2)->pcflow) != NULL) )  {
 825                 if(pcfl2 == pcfl1) {
 826
 827                   if(pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 0,optimize_level))
 828                     searching = 0;
 829                 }
 830               }
 831
 832               //rset2 = rset2->next;
 833
 834             }
 835           }
 836           rset1 = rset1->next;
 837         }
 838       }
 839     }
 840
 841   }
 842
 843 }
 844 /*-----------------------------------------------------------------*
 845  * void pic16_pCodeRegOptimeRegUsage(pBlock *pb)
 846  *-----------------------------------------------------------------*/
 847 void pic16_pCodeRegOptimizeRegUsage(int level)
 848 {
 849
 850   int passes;
 851   int saved = 0;
 852   int t = total_registers_saved;
 853
 854   if(!register_optimization)
 855     return;
 856
 857 #define OPT_PASSES 4
 858   passes = OPT_PASSES;
 859
 860   do {
 861     saved = total_registers_saved;
 862
 863     /* Identify registers used in one flow sequence */
 864     OptimizeRegUsage(pic16_dynAllocRegs,level, (OPT_PASSES-passes));
 865     OptimizeRegUsage(pic16_dynStackRegs,level, (OPT_PASSES-passes));
 866     OptimizeRegUsage(pic16_dynDirectRegs,0, (OPT_PASSES-passes));
 867
 868     if((total_registers_saved != saved)
 869         && (pic16_pcode_verbose))
 870       fprintf(stderr, " *** pass %d, Saved %d registers, total saved %d ***\n",
 871               (1+OPT_PASSES-passes),total_registers_saved-saved,total_registers_saved);
 872
 873     passes--;
 874
 875   } while( passes && ((total_registers_saved != saved) || (passes==OPT_PASSES-1)) );
 876
 877   if(total_registers_saved == t)
 878
 879   if(pic16_debug_verbose)
 880     fprintf(stderr, "No registers saved on this pass\n");
 881
 882
 883 #if 0
 884   fprintf(stderr,"dynamically allocated regs:\n");
 885   dbg_regusage(pic16_dynAllocRegs);
 886   fprintf(stderr,"stack regs:\n");
 887   dbg_regusage(pic16_dynStackRegs);
 888   fprintf(stderr,"direct regs:\n");
 889   dbg_regusage(pic16_dynDirectRegs);
 890 #endif
 891 }
 892
 893
 894 /*-----------------------------------------------------------------*
 895  * void RegsUnMapLiveRanges(set *regset)
 896  *
 897  *-----------------------------------------------------------------*/
 898 static void  RegsSetUnMapLiveRanges(set *regset)
 899 {
 900   regs *reg;
 901
 902   while(regset) {
 903     reg = regset->item;
 904     regset = regset->next;
 905
 906
 907     deleteSet(&reg->reglives.usedpCodes);
 908     deleteSet(&reg->reglives.usedpFlows);
 909     deleteSet(&reg->reglives.assignedpFlows);
 910
 911   }
 912
 913 }
 914
 915 void  pic16_RegsUnMapLiveRanges(void)
 916 {
 917
 918   RegsSetUnMapLiveRanges(pic16_dynAllocRegs);
 919   RegsSetUnMapLiveRanges(pic16_dynStackRegs);
 920   RegsSetUnMapLiveRanges(pic16_dynDirectRegs);
 921   RegsSetUnMapLiveRanges(pic16_dynProcessorRegs);
 922   RegsSetUnMapLiveRanges(pic16_dynDirectBitRegs);
 923   RegsSetUnMapLiveRanges(pic16_dynInternalRegs);
 924
 925 }