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   1 /*-------------------------------------------------------------------------
   2
   3    pcoderegs.c - post code generation register optimizations
   4
   5    Written By -  Scott Dattalo scott@dattalo.com
   6
   7    This program is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by the
   9    Free Software Foundation; either version 2, or (at your option) any
  10    later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20
  21 -------------------------------------------------------------------------*/
  22
  23 /*
  24 pcoderegs.c
  25
  26   The purpose of the code in this file is to optimize the register usage.
  27
  28 */
  29 #include <stdio.h>
  30
  31 #include "common.h"   // Include everything in the SDCC src directory
  32 #include "newalloc.h"
  33 #include "ralloc.h"
  34 #include "device.h"
  35 #include "pcode.h"
  36 #include "pcoderegs.h"
  37 #include "pcodeflow.h"
  38
  39 extern void dbg_dumpregusage(void);
  40 extern pCode * findPrevInstruction(pCode *pci);
  41 extern pBranch * pBranchAppend(pBranch *h, pBranch *n);
  42 void unlinkpCode(pCode *pc);
  43 extern int pCodeSearchCondition(pCode *pc, unsigned int cond, int contIfSkip);
  44 char *pCode2str(char *str, int size, pCode *pc);
  45 void SAFE_snprintf(char **str, size_t *size, const  char  *format, ...);
  46 int total_registers_saved=0;
  47 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 void dbg_regusage(set *fregs)
  70 {
  71         regs *reg;
  72         pCode *pcfl;
  73         pCode *pc;
  74
  75
  76         for (reg = setFirstItem(fregs) ; reg ;
  77         reg = setNextItem(fregs)) {
  78
  79                 if(elementsInSet(reg->reglives.usedpCodes)) {
  80
  81                         fprintf (stderr, "%s  addr=0x%03x rIdx=0x%03x",
  82                                 reg->name,
  83                                 reg->address,
  84                                 reg->rIdx);
  85
  86                         pcfl = setFirstItem(reg->reglives.usedpFlows);
  87                         if(pcfl)
  88                                 fprintf(stderr, "\n   used in seq");
  89
  90                         while(pcfl) {
  91                                 fprintf(stderr," 0x%03x",pcfl->seq);
  92                                 pcfl = setNextItem(reg->reglives.usedpFlows);
  93                         }
  94
  95                         pcfl = setFirstItem(reg->reglives.assignedpFlows);
  96                         if(pcfl)
  97                                 fprintf(stderr, "\n   assigned in seq");
  98
  99                         while(pcfl) {
 100                                 fprintf(stderr," 0x%03x",pcfl->seq);
 101                                 pcfl = setNextItem(reg->reglives.assignedpFlows);
 102                         }
 103
 104                         pc = setFirstItem(reg->reglives.usedpCodes);
 105                         if(pc)
 106                                 fprintf(stderr, "\n   used in instructions ");
 107
 108                         while(pc) {
 109                                 pcfl = PCODE(PCI(pc)->pcflow);
 110                                 if(pcfl)
 111                                         fprintf(stderr," 0x%03x:",pcfl->seq);
 112                                 fprintf(stderr,"0x%03x",pc->seq);
 113
 114                                 pc = setNextItem(reg->reglives.usedpCodes);
 115                         }
 116
 117                         fprintf(stderr, "\n");
 118                 }
 119         }
 120 }
 121
 122 /*-----------------------------------------------------------------*
 123 *
 124 *-----------------------------------------------------------------*/
 125 void dbg_dumpregusage(void)
 126 {
 127
 128         fprintf(stderr,"***  Register Usage  ***\n");
 129         fprintf(stderr,"InternalRegs:\n");
 130         dbg_regusage(dynInternalRegs);
 131         fprintf(stderr,"AllocRegs:\n");
 132         dbg_regusage(dynAllocRegs);
 133         fprintf(stderr,"StackRegs:\n");
 134         dbg_regusage(dynStackRegs);
 135         fprintf(stderr,"DirectRegs:\n");
 136         dbg_regusage(dynDirectRegs);
 137         fprintf(stderr,"DirectBitRegs:\n");
 138         dbg_regusage(dynDirectBitRegs);
 139         fprintf(stderr,"ProcessorRegs:\n");
 140         dbg_regusage(dynProcessorRegs);
 141
 142 }
 143
 144
 145 /*-----------------------------------------------------------------*
 146 * void pCodeRegMapLiveRangesInFlow(pCodeFlow *pcfl)
 147 *-----------------------------------------------------------------*/
 148 void pCodeRegMapLiveRangesInFlow(pCodeFlow *pcfl)
 149 {
 150
 151         pCode *pc=NULL;
 152         pCode *pcprev=NULL;
 153
 154         regs *reg;
 155
 156         if(!pcfl)
 157                 return;
 158
 159
 160         pc = findNextInstruction(pcfl->pc.next);
 161
 162         while(isPCinFlow(pc,PCODE(pcfl))) {
 163
 164
 165                 reg = getRegFromInstruction(pc);
 166
 167                 if(reg) {
 168                 /*
 169                 fprintf(stderr, "flow seq %d, inst seq %d  %s  ",PCODE(pcfl)->seq,pc->seq,reg->name);
 170                 fprintf(stderr, "addr = 0x%03x, type = %d  rIdx=0x%03x\n",
 171                 reg->address,reg->type,reg->rIdx);
 172                         */
 173
 174                         addSetIfnotP(& (PCFL(pcfl)->registers), reg);
 175
 176                         if((PCC_REGISTER | PCC_LITERAL) & PCI(pc)->inCond)
 177                                 addSetIfnotP(& (reg->reglives.usedpFlows), pcfl);
 178
 179                         if(PCC_REGISTER & PCI(pc)->outCond)
 180                                 addSetIfnotP(& (reg->reglives.assignedpFlows), pcfl);
 181
 182                         addSetIfnotP(& (reg->reglives.usedpCodes), pc);
 183                 }
 184
 185
 186                 pcprev = pc;
 187                 pc = findNextInstruction(pc->next);
 188
 189         }
 190
 191 }
 192
 193 /*-----------------------------------------------------------------*
 194 * void pCodeRegMapLiveRanges(pBlock *pb)
 195 *-----------------------------------------------------------------*/
 196 void pCodeRegMapLiveRanges(pBlock *pb)
 197 {
 198         pCode *pcflow;
 199
 200         for( pcflow = findNextpCode(pb->pcHead, PC_FLOW);
 201         pcflow != NULL;
 202         pcflow = findNextpCode(pcflow->next, PC_FLOW) ) {
 203
 204                 if(!isPCFL(pcflow)) {
 205                         fprintf(stderr, "pCodeRegMapLiveRanges - pcflow is not a flow object ");
 206                         continue;
 207                 }
 208                 pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 209         }
 210
 211 #if 0
 212         for( pcflow = findNextpCode(pb->pcHead, PC_FLOW);
 213         pcflow != NULL;
 214         pcflow = findNextpCode(pcflow->next, PC_FLOW) ) {
 215
 216                 regs *r = setFirstItem(PCFL(pcflow)->registers);
 217                 fprintf(stderr,"flow seq %d\n", pcflow->seq);
 218
 219                 while (r) {
 220                         fprintf(stderr, "  %s\n",r->name);
 221                         r = setNextItem(PCFL(pcflow)->registers);
 222
 223                 }
 224
 225         }
 226 #endif
 227
 228         //  dbg_dumpregusage();
 229
 230 }
 231
 232
 233 /*-----------------------------------------------------------------*
 234 *
 235 *-----------------------------------------------------------------*/
 236 static void Remove1pcode(pCode *pc, regs *reg, int debug_code)
 237 {
 238
 239         pCode *pcn=NULL;
 240
 241         if(!reg || !pc)
 242                 return;
 243
 244         deleteSetItem (&(reg->reglives.usedpCodes),pc);
 245
 246         if(PCI(pc)->label) {
 247                 pcn = findNextInstruction(pc->next);
 248
 249                 if(pcn)
 250                         PCI(pcn)->label = pBranchAppend(PCI(pcn)->label,PCI(pc)->label);
 251         }
 252
 253         if(PCI(pc)->cline) {
 254                 if(!pcn)
 255                         pcn = findNextInstruction(pc->next);
 256
 257                 if(pcn) {
 258                         if(PCI(pcn)->cline) {
 259                                 //fprintf(stderr, "source line has been optimized completely out\n");
 260                                 //pc->print(stderr,pc);
 261                         } else {
 262                                 PCI(pcn)->cline = PCI(pc)->cline;
 263                         }
 264                 }
 265         }
 266
 267
 268         if(1){
 269         /*
 270         Debug stuff. Comment out the instruction we're about to delete.
 271                 */
 272
 273                 char buff1[256];
 274                 size_t size = 256;
 275
 276                 char *pbuff,**ppbuff;
 277                 pbuff = buff1;
 278                 ppbuff = &pbuff;
 279
 280                 SAFE_snprintf(ppbuff,&size, ";%d", debug_code);
 281                 pCode2str(*ppbuff, size, pc);
 282                 pCodeInsertBefore(pc, newpCodeCharP(buff1));
 283                 //fprintf(stderr,"removing instruction:\n%s\n",buff1);
 284         }
 285
 286         pc->destruct(pc);
 287
 288 }
 289
 290 /*-----------------------------------------------------------------*
 291 * void RemoveRegsFromSet(set *regset)
 292 *
 293 *-----------------------------------------------------------------*/
 294 void  RemoveRegsFromSet(set *regset)
 295 {
 296         regs *reg;
 297         int used;
 298
 299         while(regset) {
 300                 reg = regset->item;
 301                 regset = regset->next;
 302
 303                 used = elementsInSet(reg->reglives.usedpCodes);
 304
 305                 if(used <= 1) {
 306
 307                         //fprintf(stderr," reg %s isfree=%d, wasused=%d\n",reg->name,reg->isFree,reg->wasUsed);
 308                         if(used == 0) {
 309                                 //fprintf(stderr," getting rid of reg %s\n",reg->name);
 310                                 reg->isFree = 1;
 311                                 reg->wasUsed = 0;
 312                         } else {
 313                                 pCode *pc;
 314
 315
 316                                 pc = setFirstItem(reg->reglives.usedpCodes);
 317
 318                                 if(reg->type == REG_SFR || reg->type == REG_STK || reg->isPublic || reg->isExtern) {
 319                                         //fprintf(stderr, "not removing SFR reg %s even though used only once\n",reg->name);
 320                                         continue;
 321                                 }
 322
 323
 324                                 if(isPCI(pc)) {
 325                                         if(PCI(pc)->label) {
 326                                                 pCode *pcn = findNextInstruction(pc->next);
 327
 328                                                 if(pcn && PCI(pcn)->label) {
 329                                                         //fprintf(stderr,"can't delete instruction with label...\n");
 330                                                         //pc->print(stderr,pc);
 331                                                         continue;
 332                                                 }
 333                                                 /* Move the label to the next instruction */
 334
 335                                                 PCI(pcn)->label = PCI(pc)->label;
 336
 337                                         }
 338
 339                                         if(isPCI_SKIP(pc)) {
 340                                                 regs *r = getRegFromInstruction(pc);
 341                                                 fprintf(stderr, "WARNING, a skip instruction is being optimized out\n");
 342                                                 pc->print(stderr,pc);
 343                                                 fprintf(stderr,"reg %s, type =%d\n",r->name, r->type);
 344                                         }
 345                                         //fprintf(stderr," removing reg %s because it is used only once\n",reg->name);
 346                                         Remove1pcode(pc, reg, 1);
 347                                         /*
 348                                         unlinkpCode(pc);
 349                                         deleteSetItem (&(reg->reglives.usedpCodes),pc);
 350                                         */
 351                                         reg->isFree = 1;
 352                                         reg->wasUsed = 0;
 353                                         total_registers_saved++;  // debugging stats.
 354                                 }
 355                         }
 356                 }
 357
 358         }
 359 }
 360 /*-----------------------------------------------------------------*
 361 * void RemoveUnusedRegisters(void)
 362 *
 363 *-----------------------------------------------------------------*/
 364 void RemoveUnusedRegisters(void)
 365 {
 366         /* First, get rid of registers that are used only one time */
 367
 368         //RemoveRegsFromSet(dynInternalRegs);
 369         RemoveRegsFromSet(dynAllocRegs);
 370         RemoveRegsFromSet(dynStackRegs);
 371         /*
 372         don't do DirectRegs yet - there's a problem with arrays
 373         RemoveRegsFromSet(dynDirectRegs);
 374         */
 375         RemoveRegsFromSet(dynDirectBitRegs);
 376
 377         if(total_registers_saved) DFPRINTF((stderr, " *** Saved %d registers ***\n", total_registers_saved));
 378 }
 379
 380
 381 /*-----------------------------------------------------------------*
 382 *
 383 *-----------------------------------------------------------------*/
 384 static void Remove2pcodes(pCode *pcflow, pCode *pc1, pCode *pc2, regs *reg, int can_free)
 385 {
 386         static int debug_code=99;
 387         if(!reg)
 388                 return;
 389
 390         //fprintf(stderr,"%s\n",__FUNCTION__);
 391         if(pc1)
 392                 Remove1pcode(pc1, reg, debug_code++);
 393
 394         if(pc2) {
 395                 Remove1pcode(pc2, reg, debug_code++);
 396                 deleteSetItem (&(PCFL(pcflow)->registers), reg);
 397
 398                 if(can_free) {
 399                         reg->isFree = 1;
 400                         reg->wasUsed = 0;
 401                 }
 402
 403         }
 404
 405         pCodeRegMapLiveRangesInFlow(PCFL(pcflow));
 406 }
 407
 408 /*-----------------------------------------------------------------*
 409 *
 410 *-----------------------------------------------------------------*/
 411 int regUsedinRange(pCode *pc1, pCode *pc2, regs *reg)
 412 {
 413         int i=0;
 414         regs *testreg;
 415
 416         do {
 417                 testreg = getRegFromInstruction(pc1);
 418                 if(testreg && (testreg->rIdx == reg->rIdx)) {
 419                         return 1;
 420                 }
 421
 422                 pc1 = findNextInstruction(pc1->next);
 423
 424         } while (pc1 && (pc1 != pc2) && (i++ < 100)) ;
 425
 426         if(i >= 100)
 427                 fprintf(stderr, "warning, regUsedinRange searched through too many pcodes\n");
 428
 429         return 0;
 430 }
 431
 432 /*-----------------------------------------------------------------*
 433 * void pCodeOptime2pCodes(pCode *pc1, pCode *pc2)
 434 *
 435 * ADHOC pattern checking
 436 * Now look for specific sequences that are easy to optimize.
 437 * Many of these sequences are characteristic of the compiler
 438 * (i.e. it'd probably be a waste of time to apply these adhoc
 439 * checks to hand written assembly.)
 440 *
 441 *
 442 *-----------------------------------------------------------------*/
 443 int pCodeOptime2pCodes(pCode *pc1, pCode *pc2, pCode *pcfl_used, regs *reg, int can_free, int optimize_level)
 444 {
 445         pCode *pct1, *pct2;
 446         regs  *reg1, *reg2;
 447
 448         int t = total_registers_saved;
 449
 450         if(pc2->seq < pc1->seq) {
 451                 pct1 = pc2;
 452                 pc2 = pc1;
 453                 pc1 = pct1;
 454         }
 455
 456         //fprintf(stderr,"pCodeOptime2pCodes\n");
 457         //pc1->print(stderr,pc1);
 458         //pc2->print(stderr,pc2);
 459
 460         if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_MOVFW) ){
 461                 pCode *newpc;
 462                 int regUsed = 0;
 463                 int wUsed   = 0;
 464                 int wSaved  = 0;
 465                 /*
 466                 clrf  reg    ; pc1
 467                 stuff...
 468                 movf  reg,w  ; pc2
 469
 470                   can be replaced with (only if following instructions are not going to use W and reg is not used again later)
 471
 472                         stuff...
 473                         movlw 0 or clrf  reg
 474                 */
 475                 DFPRINTF((stderr, "   optimising CLRF reg ... MOVF reg,W to ... MOVLW 0\n"));
 476                 pct2 = findNextInstruction(pc2->next);
 477
 478                 if(pct2 && PCI(pct2)->op == POC_MOVWF) {
 479                         wSaved = wUsed = 1; /* Maybe able to replace with clrf pc2->next->reg. */
 480                 } else {
 481                         wUsed = pCodeSearchCondition(pct2,PCC_W,1) > 0;
 482                 }
 483                 regUsed = regUsedinRange(pct2,0,reg);
 484                 if ((regUsed&&wUsed) || (pCodeSearchCondition(pct2,PCC_Z,0) > 1)) {
 485                         /* Do not optimise as exisiting code is required. */
 486                 } else {
 487                         /* Can optimise. */
 488                         if(regUsed) {
 489                                 newpc = newpCode(POC_CLRF, PCI(pc1)->pcop);
 490                         } else if(wSaved && !wUsed) {
 491                                 newpc = newpCode(POC_CLRF, PCI(pct2)->pcop);
 492                                 pct2->destruct(pct2);
 493                         } else {
 494                                 newpc = newpCode(POC_MOVLW, newpCodeOpLit(0));
 495                         }
 496
 497                         pCodeInsertAfter(pc2, newpc);
 498                         PCI(newpc)->pcflow = PCFL(pcfl_used);
 499                         newpc->seq = pc2->seq;
 500
 501                         Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 502                         total_registers_saved++;  // debugging stats.
 503                 }
 504         } else if((PCI(pc1)->op == POC_CLRF) && (PCI(pc2)->op == POC_IORFW) ){
 505                 DFPRINTF((stderr, "   optimising CLRF/IORFW\n"));
 506
 507                 pct2 = findNextInstruction(pc2->next);
 508
 509                 if(pCodeSearchCondition(pct2, PCC_Z,0) > 0) {
 510                         pct2 = newpCode(POC_IORLW, newpCodeOpLit(0));
 511                         pct2->seq = pc2->seq;
 512                         PCI(pct2)->pcflow = PCFL(pcfl_used);
 513                         pCodeInsertAfter(pc1,pct2);
 514                 }
 515                 Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 516                 total_registers_saved++;  // debugging stats.
 517
 518         }  else if(PCI(pc1)->op == POC_MOVWF) {
 519                 // Optimising MOVWF reg ...
 520
 521                 pct2 = findNextInstruction(pc2->next);
 522
 523                 if(PCI(pc2)->op == POC_MOVFW) {
 524                         // Optimising MOVWF reg ... MOVF reg,W
 525
 526                         if(PCI(pct2)->op == POC_MOVWF) {
 527                         /*
 528                         Change:
 529
 530                           movwf   reg    ; pc1
 531                           stuff...
 532                           movf    reg,w  ; pc2
 533                           movwf   reg2   ; pct2
 534
 535                                 To: ( as long as 'stuff' does not use reg2 or if following instructions do not use W or reg is not used later)
 536
 537                                   movwf   reg2
 538                                   stuff...
 539
 540                                 */
 541                                 reg2 = getRegFromInstruction(pct2);
 542                                 /* Check reg2 is not used for something else before it is loaded with reg */
 543                                 if (reg2 && !regUsedinRange(pc1,pc2,reg2)) {
 544                                         pCode *pct3 = findNextInstruction(pct2->next);
 545                                         /* Check following instructions are not relying on the use of W or the Z flag condiction */
 546                                         if ((pCodeSearchCondition(pct3,PCC_Z,0) < 1) || (pCodeSearchCondition(pct3,PCC_W,0) < 1)) {
 547                                                 DFPRINTF((stderr, "   optimising MOVF reg ... MOVF reg,W MOVWF reg2 to MOVWF reg2 ...\n"));
 548                                                 pct2->seq = pc1->seq;
 549                                                 unlinkpCode(pct2);
 550                                                 pCodeInsertBefore(pc1,pct2);
 551                                                 if(regUsedinRange(pct2,0,reg))
 552                                                         Remove2pcodes(pcfl_used, pc2, NULL, reg, can_free);
 553                                                 else
 554                                                         Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 555
 556                                                 total_registers_saved++;  // debugging stats.
 557                                                 return 1;
 558                                         }
 559                                 }
 560                         }
 561                 }
 562
 563                 pct1 = findPrevInstruction(pc1->prev);
 564                 if(pct1 && (PCI(pct1)->pcflow == PCI(pc1)->pcflow)) {
 565
 566                         if ( (PCI(pct1)->op == POC_MOVFW) &&
 567                                 (PCI(pc2)->op == POC_MOVFW)) {
 568
 569                                 reg1 = getRegFromInstruction(pct1);
 570                                 if(reg1 && !regUsedinRange(pc1,pc2,reg1)) {
 571                                         DFPRINTF((stderr, "   optimising MOVF reg1,W MOVWF reg ... MOVF reg,W\n"));
 572                                         /*
 573                                         Change:
 574
 575                                                 movf   reg1,w
 576                                                 movwf  reg
 577
 578                                                 stuff...
 579                                                 movf   reg,w
 580
 581                                         To:
 582
 583                                                 stuff...
 584
 585                                                 movf   reg1,w
 586
 587                                         Or, if we're not deleting the register then the "To" is:
 588
 589                                                 stuff...
 590
 591                                                 movf   reg1,w
 592                                                 movwf  reg
 593                                         */
 594                                         pct2 = newpCode(PCI(pc2)->op, PCI(pct1)->pcop);
 595                                         pCodeInsertAfter(pc2, pct2);
 596                                         PCI(pct2)->pcflow = PCFL(pcfl_used);
 597                                         pct2->seq = pc2->seq;
 598
 599                                         if(can_free) {
 600                                                 Remove2pcodes(pcfl_used, pc1, pc2, reg, can_free);
 601                                         } else {
 602                                         /* If we're not freeing the register then that means (probably)
 603                                                 * the register is needed somewhere else.*/
 604                                                 unlinkpCode(pc1);
 605                                                 pCodeInsertAfter(pct2, pc1);
 606
 607                                                 Remove2pcodes(pcfl_used, pc2, NULL, reg, can_free);
 608                                         }
 609
 610                                         Remove2pcodes(pcfl_used, pct1, NULL, reg1, 0);
 611                                         total_registers_saved++;  // debugging stats.
 612
 613                                 }
 614                                 /* Note this else if is same conditional as the if - DELETE ME
 615                                 } else if ( (PCI(pct1)->op == POC_MOVWF) &&
 616                                         (PCI(pc2)->op == POC_MOVFW)) {
 617                                         DFPRINTF(stderr, "   optimising MOVF reg1,W MOVWF reg ... MOVF reg,W\n");
 618                                         if(optimize_level > 1 && can_free) {
 619                                                 pct2 = newpCode(POC_MOVFW, PCI(pc1)->pcop);
 620                                                 pCodeInsertAfter(pc2, pct2);
 621                                                 Remove2pcodes(pcfl_used, pc1, pc2, reg, 1);
 622                                         total_registers_saved++;  // debugging stats.
 623                                 }
 624                                 */
 625                         }
 626                 }
 627   }
 628
 629   return (total_registers_saved != t);
 630 }
 631
 632 /*-----------------------------------------------------------------*
 633 * void pCodeRegOptimeRegUsage(pBlock *pb)
 634 *-----------------------------------------------------------------*/
 635 void OptimizeRegUsage(set *fregs, int optimize_multi_uses, int optimize_level)
 636 {
 637         regs *reg;
 638         int used;
 639         pCode *pc1=NULL, *pc2=NULL;
 640
 641
 642         while(fregs) {
 643                 pCode *pcfl_used, *pcfl_assigned;
 644
 645                 /* Step through the set by directly accessing the 'next' pointer.
 646                 * We could also step through by using the set API, but the
 647                 * the (debug) calls to print instructions affect the state
 648                 * of the set pointers */
 649
 650                 reg = fregs->item;
 651                 fregs = fregs->next;
 652                 /*
 653                 if (strcmp(reg->name,"_SubState")==0)
 654                 fprintf(stderr,"Reg: %s\n",reg->name);
 655                 */
 656
 657                 if(reg->type == REG_SFR || reg->type == REG_STK || reg->isPublic || reg->isExtern|| reg->isFixed) {
 658                         //fprintf(stderr,"skipping SFR: %s\n",reg->name);
 659                         continue;
 660                 }
 661
 662                 pcfl_used = setFirstItem(reg->reglives.usedpFlows);
 663                 pcfl_assigned = setFirstItem(reg->reglives.assignedpFlows);
 664
 665                 used = elementsInSet(reg->reglives.usedpCodes);
 666                 if(used == 2) {
 667                         /*
 668                         In this section, all registers that are used in only in two
 669                         instructions are examined. If possible, they're optimized out.
 670                         */
 671
 672                         /*
 673                         fprintf (stderr, "OptimizeRegUsage: %s  addr=0x%03x rIdx=0x%03x type=%d used=%d\n",
 674                         reg->name,
 675                         reg->address,
 676                         reg->rIdx, reg->type, used);
 677                         */
 678                         pc1 = setFirstItem(reg->reglives.usedpCodes);
 679                         pc2 = setNextItem(reg->reglives.usedpCodes);
 680
 681                         if(pcfl_used && pcfl_assigned) {
 682                                 /*
 683                                 expected case - the register has been assigned a value and is
 684                                 subsequently used
 685                                 */
 686
 687                                 //fprintf(stderr," used only twice\n");
 688                                 if(pcfl_used->seq == pcfl_assigned->seq) {
 689
 690                                         //fprintf(stderr, "  and used in same flow\n");
 691
 692                                         pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 1,optimize_level);
 693
 694                                 } else {
 695                                         // fprintf(stderr, "  and used in different flows\n");
 696
 697                                 }
 698
 699                         } else if(pcfl_used) {
 700
 701                                 /* register has been used twice without ever being assigned */
 702                                 fprintf(stderr,"WARNING %s: reg %s used without being assigned\n",__FUNCTION__,reg->name);
 703
 704                         } else {
 705                                 fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 706                                 Remove2pcodes(pcfl_assigned, pc1, pc2, reg, 1);
 707                                 total_registers_saved++;  // debugging stats.
 708                         }
 709                 } else {
 710
 711                         /* register has been used either once, or more than twice */
 712
 713                         if(used && !pcfl_used && pcfl_assigned) {
 714                                 pCode *pc;
 715
 716                                 fprintf(stderr,"WARNING %s: reg %s assigned without being used\n",__FUNCTION__,reg->name);
 717
 718                                 pc = setFirstItem(reg->reglives.usedpCodes);
 719                                 while(pc) {
 720
 721                                         pcfl_assigned = PCODE(PCI(pc)->pcflow);
 722                                         Remove1pcode(pc, reg,2);
 723
 724                                         deleteSetItem (&(PCFL(pcfl_assigned)->registers), reg);
 725                                         /*
 726                                         deleteSetItem (&(reg->reglives.usedpCodes),pc);
 727                                         pc->destruct(pc);
 728                                         */
 729                                         pc = setNextItem(reg->reglives.usedpCodes);
 730                                 }
 731
 732
 733                                 reg->isFree = 1;
 734                                 reg->wasUsed = 0;
 735
 736                                 total_registers_saved++;  // debugging stats.
 737                         } else if( (used > 2) && optimize_multi_uses) {
 738
 739                                 set *rset1=NULL;
 740                                 set *rset2=NULL;
 741                                 int searching=1;
 742
 743                                 pCodeFlow *pcfl1=NULL, *pcfl2=NULL;
 744
 745                                 /* examine the number of times this register is used */
 746
 747
 748                                 rset1 = reg->reglives.usedpCodes;
 749                                 while(rset1 && searching) {
 750
 751                                         pc1 = rset1->item;
 752                                         rset2 = rset1->next;
 753
 754                                         if(pc1 && isPCI(pc1) &&  ( (pcfl1 = PCI(pc1)->pcflow) != NULL) ) {
 755
 756                                                 //while(rset2 && searching) {
 757                                                 if(rset2) {
 758
 759                                                         pc2 = rset2->item;
 760                                                         if(pc2 && isPCI(pc2)  &&  ( (pcfl2 = PCI(pc2)->pcflow) != NULL) )  {
 761                                                                 if(pcfl2 == pcfl1) {
 762
 763                                                                         if(pCodeOptime2pCodes(pc1, pc2, pcfl_used, reg, 0,optimize_level))
 764                                                                                 searching = 0;
 765                                                                 }
 766                                                         }
 767
 768                                                         //rset2 = rset2->next;
 769
 770                                                 }
 771                                         }
 772                                         rset1 = rset1->next;
 773                                 }
 774                         }
 775                 }
 776         }
 777 }
 778
 779 /*-----------------------------------------------------------------*
 780 * void pCodeRegOptimeRegUsage(pBlock *pb)
 781 *-----------------------------------------------------------------*/
 782 void pCodeRegOptimizeRegUsage(int level)
 783 {
 784
 785         int passes;
 786         int saved = 0;
 787         int t = total_registers_saved;
 788
 789         if(!register_optimization)
 790                 return;
 791 #define OPT_PASSES 4
 792         passes = OPT_PASSES;
 793
 794         do {
 795                 saved = total_registers_saved;
 796
 797                 /* Identify registers used in one flow sequence */
 798                 OptimizeRegUsage(dynAllocRegs,level, (OPT_PASSES-passes));
 799                 OptimizeRegUsage(dynStackRegs,level, (OPT_PASSES-passes));
 800                 OptimizeRegUsage(dynDirectRegs,0, (OPT_PASSES-passes));
 801
 802                 if(total_registers_saved != saved)
 803                         DFPRINTF((stderr, " *** pass %d, Saved %d registers, total saved %d ***\n",
 804                         (1+OPT_PASSES-passes),total_registers_saved-saved,total_registers_saved));
 805
 806                 passes--;
 807
 808         } while( passes && ((total_registers_saved != saved) || (passes==OPT_PASSES-1)) );
 809
 810         if(total_registers_saved == t)
 811                 DFPRINTF((stderr, "No registers saved on this pass\n"));
 812
 813
 814         /*
 815                 fprintf(stderr,"dynamically allocated regs:\n");
 816                 dbg_regusage(dynAllocRegs);
 817                 fprintf(stderr,"stack regs:\n");
 818                 dbg_regusage(dynStackRegs);
 819                 fprintf(stderr,"direct regs:\n");
 820                 dbg_regusage(dynDirectRegs);
 821         */
 822 }
 823
 824
 825 /*-----------------------------------------------------------------*
 826 * void RegsUnMapLiveRanges(set *regset)
 827 *
 828 *-----------------------------------------------------------------*/
 829 void  RegsSetUnMapLiveRanges(set *regset)
 830 {
 831         regs *reg;
 832
 833         while(regset) {
 834                 reg = regset->item;
 835                 regset = regset->next;
 836
 837
 838                 deleteSet(&reg->reglives.usedpCodes);
 839                 deleteSet(&reg->reglives.usedpFlows);
 840                 deleteSet(&reg->reglives.assignedpFlows);
 841
 842         }
 843
 844 }
 845
 846 void  RegsUnMapLiveRanges(void)
 847 {
 848
 849         RegsSetUnMapLiveRanges(dynAllocRegs);
 850         RegsSetUnMapLiveRanges(dynStackRegs);
 851         RegsSetUnMapLiveRanges(dynDirectRegs);
 852         RegsSetUnMapLiveRanges(dynProcessorRegs);
 853         RegsSetUnMapLiveRanges(dynDirectBitRegs);
 854         RegsSetUnMapLiveRanges(dynInternalRegs);
 855
 856 }