sdcc/src/mos6502/peeph.def

   1 ////////////////////////////////////////////////////////
   2 // Rules for common codegen patterns
   3 ////////////////////////////////////////////////////////
   4
   5 replace restart {
   6         sta     %1
   7         stx     %2
   8         lda     %1
   9         sta     %3
  10         lda     %2
  11         sta     %4
  12 } by {
  13         sta     %1
  14         stx     %2
  15     ; Peephole Function_Entry_1 - eliminated unnecessary lda %1
  16         sta     %3
  17     ; Peephole Function_Entry_1 - eliminated unnecessary lda %2
  18         stx     %4
  19 } if notVolatile(%1), notVolatile(%2)
  20
  21 replace restart {
  22         sta     %1
  23         stx     %2
  24         lda     %2
  25         sta     %4
  26         lda     %1
  27         sta     %3
  28 } by {
  29         sta     %1
  30         stx     %2
  31     ; Peephole Function_Entry_1a - eliminated unnecessary lda %1
  32         sta     %3
  33     ; Peephole Function_Entry_1a - eliminated unnecessary lda %2
  34         stx     %4
  35 } if notVolatile(%1), notVolatile(%2)
  36
  37 replace restart {
  38         sta     %1
  39         stx     %2
  40         lda     %1
  41         ldx     %2
  42 } by {
  43         sta     %1
  44         stx     %2
  45     ; Peephole Function_Entry_2 - eliminated redundant lda %1/ldx %2
  46 } if notVolatile(%1), notVolatile(%2)
  47
  48 replace restart {
  49         sta     %1
  50         stx     %2
  51         ldx     %2
  52         lda     %1
  53 } by {
  54         sta     %1
  55         stx     %2
  56     ; Peephole Function_Entry_2a - eliminated redundant lda %1/ldx %2
  57 } if notVolatile(%1), notVolatile(%2)
  58
  59 replace restart {
  60         ldx     %1
  61         ldy     %2
  62         clc
  63         txa
  64         adc     %3
  65         sta     %4
  66         tya
  67         adc     %5
  68         sta     %6
  69 } by {
  70     ; Peephole genpointer YX   - eliminated ldx/ldy
  71         lda     %1
  72     ; Peephole genpointer YX   - replaced txa with lda
  73         clc
  74         adc     %3
  75         sta     %4
  76         lda     %2
  77     ; Peephole genpointer YX   - replaced tya with lda
  78         adc     %5
  79         sta     %6
  80 }
  81
  82 // TODO: Enable when notUsed() gets implemented!
  83 //replace restart {
  84 //      lda     %1
  85 //      ldx     %2
  86 //      clc
  87 //      adc     %3
  88 //      sta     %4
  89 //      txa
  90 //      adc     %5
  91 //      sta     %6
  92 //} by {
  93 //      lda     %1
  94 //      ; Peephole genpointer XA   - eliminated ldx
  95 //      clc
  96 //      adc     %3
  97 //      sta     %4
  98 //      lda     %2
  99 //      ; Peephole genpointer XA   - replaced txa with lda
 100 //      adc     %5
 101 //      sta     %6
 102 //} if notUsed('x')
 103
 104
 105 ////////////////////////////////////////////////////////
 106 // Remove unnecessary loads
 107 ////////////////////////////////////////////////////////
 108
 109 replace restart {
 110         sta     %1
 111         lda     %1
 112 } by {
 113         sta     %1
 114     ; Peephole load 1 - removed redundant lda
 115 } if notVolatile(%1), notUsed('n' 'z')
 116
 117 // ora is cheaper than lda (except for lda from immediate, but that can't happen for the two rules below)
 118 replace restart {
 119         sta     %1
 120         lda     %1
 121 } by {
 122         sta     %1
 123         ora     #0x00
 124     ; Peephole load 1a - replaced redundant lda by ora
 125 } if notVolatile(%1)
 126
 127 replace restart {
 128         sta     %1, %2
 129         lda     %1, %2
 130 } by {
 131         sta     %1, %2
 132     ; Peephole load 2 - removed redundant lda
 133 } if notVolatile(%1), notUsed('n' 'z')
 134
 135 replace restart {
 136         sta     %1, %2
 137         lda     %1, %2
 138 } by {
 139         sta     %1, %2
 140         ora     #0x00
 141     ; Peephole load 2a - replaced redundant lda by ora
 142 } if notVolatile(%1)
 143
 144 replace restart {
 145         stx     %1
 146         ldx     %1
 147 } by {
 148         stx     %1
 149     ; Peephole load 3 - eliminated redundant ldx
 150 } if notVolatile(%1), notUsed('n' 'z')
 151
 152 replace restart {
 153         sty     %1
 154         ldy     %1
 155 } by {
 156         sty     %1
 157     ; Peephole load 4 - eliminated redundant ldy
 158 } if notVolatile(%1), notUsed('n' 'z')
 159
 160 ////////////////////////////////////////////////////////
 161 // Remove dead loads
 162 ////////////////////////////////////////////////////////
 163
 164 replace restart {
 165         %1      %2, %4
 166         %1      %3
 167 } by {
 168     ; Peephole load 5 - eliminated dead %1 %2
 169         %1      %3
 170 } if same(%1 'lda' 'ldx' 'ldy'), notVolatile(%2)
 171
 172
 173 replace restart {
 174         %1      %2
 175         %1      %3, %4
 176 } by {
 177     ; Peephole load 6 - eliminated dead %1 %2
 178         %1      %3, %4
 179 } if same(%1 'lda' 'ldx' 'ldy'), notVolatile(%2)
 180
 181 replace restart {
 182         %1      %2, %4
 183         %1      %3, %5
 184 } by {
 185     ; Peephole load 7 - eliminated dead %1 %2
 186         %1      %3, %5
 187 } if same(%1 'lda' 'ldx' 'ldy'), notVolatile(%2)
 188
 189
 190 replace restart {
 191         %1      %2
 192         %1      %3
 193 } by {
 194     ; Peephole load 8 - eliminated dead %1 %2
 195         %1      %3
 196 } if same(%1 'lda' 'ldx' 'ldy'), notVolatile(%2)
 197
 198 replace restart {
 199         ldx %1
 200         %2
 201 } by {
 202         ; Peephole load 9 - removed dead ldx followed by %2
 203         %2
 204 } if same(%2 'tax' 'tsx'), notVolatile(%1)
 205
 206 replace restart {
 207         ldy %1
 208         tay
 209 } by {
 210         ; Peephole load 10 - removed dead ldy followed by tay
 211         tay
 212 } if notVolatile(%1)
 213
 214 replace restart {
 215         lda     %1
 216         %2
 217 } by {
 218         ; Peephole load 11 - removed dead lda
 219         %2
 220 } if same(%2 'txa' 'tya' 'pla'), notVolatile(%1)
 221
 222 replace restart {
 223         lda     %4
 224         %1      %2
 225         lda     %3
 226 } by {
 227         ; Peephole load 12 - removed dead lda not followed by store or branch
 228         %1      %2
 229         lda     %3
 230 } if notSame(%1 'sta' 'adc' 'sbc' 'cmp' 'bne' 'beq' 'bpl' 'bmi' 'bcc' 'bcs' 'jsr' 'jmp'), notSame(%2 'a'), notVolatile(%4)
 231
 232 replace restart {
 233         ldx     %4
 234         %1      %2
 235         ldx     %3
 236 } by {
 237         ; Peephole load 13 - removed dead ldx not followed by store or branch
 238         %1      %2
 239         ldx     %3
 240 } if notSame(%1 'stx' 'cpx' 'bne' 'beq' 'bpl' 'bmi' 'jsr' 'jmp'), notVolatile(%4)
 241
 242 replace restart {
 243         ldy     %4
 244         %1      %2
 245         ldy     %3
 246 } by {
 247         ; Peephole load 14 - removed dead ldy  not followed by store or branch
 248         %1      %2
 249         ldy     %3
 250 } if notSame(%1 'sty' 'cpy' 'bne' 'beq' 'bpl' 'bmi' 'jsr' 'jmp'), notVolatile(%4)
 251
 252 replace restart {
 253         lda     %3
 254         %1
 255         lda     %2
 256 } by {
 257         ; Peephole load 15 - removed dead lda
 258         %1
 259         lda     %2
 260 } if notSame(%1 'pha' 'php' 'tax' 'tay'), notVolatile(%3)
 261
 262 replace restart {
 263         ldx     %3
 264         %1
 265         ldx     %2
 266 } by {
 267         ; Peephole load 16 - removed dead ldx
 268         %1
 269         ldx     %2
 270 } if notSame(%1 'txa' 'txs' 'phx'), notVolatile(%3)
 271
 272 replace restart {
 273         ldy     %3
 274         %1
 275         ldy     %2
 276 } by {
 277         ; Peephole load 17 - removed dead ldy
 278         %1
 279         ldy     %2
 280 } if notSame(%1 'tya' 'phy'), notVolatile(%3)
 281
 282 ////////////////////////////////////////////////////////
 283 // Remove dead register operation/transfers
 284 ////////////////////////////////////////////////////////
 285
 286 replace restart {
 287         %1
 288         lda     %2
 289 } by {
 290         ; Peephole regop 1 - removed dead %1 followed by lda
 291         lda     %2
 292 } if same(%1 'txa' 'tya')
 293
 294 replace restart {
 295         %1 %3
 296         lda     %2
 297 } by {
 298         ; Peephole regop 2 - removed dead %1 followed by lda
 299         lda     %2
 300 } if same(%1 'and' 'eor' 'ora'), notVolatile(%3)
 301
 302 replace restart {
 303         %1
 304         ldx     %2
 305 } by {
 306         ; Peephole regop 3 - removed dead %1 followed by ldx
 307         ldx     %2
 308 } if same(%1 'tax' 'tsx' 'inx' 'dex' )
 309
 310 replace restart {
 311         %1
 312         tsx
 313 } by {
 314         ; Peephole regop 4 - removed dead %1 followed by tsx
 315         tsx
 316 } if same(%1 'tax' 'inx' 'dex' )
 317
 318 replace restart {
 319         %1
 320         tax
 321 } by {
 322         ; Peephole regop 5 - removed dead %1 followed by tax
 323         tax
 324 } if same(%1 'tsx' 'inx' 'dex' )
 325
 326 replace restart {
 327         %1
 328         ldy     %2
 329 } by {
 330         ; Peephole regop 6 - removed dead %1 followed by ldy
 331         ldy     %2
 332 } if same(%1 'tay' 'iny' 'dey' )
 333
 334 replace restart {
 335         tax
 336         txa
 337 } by {
 338         tax
 339         ; Peephole regop 7 - removed redundant txa
 340 }
 341
 342 replace restart {
 343         tay
 344         tya
 345 } by {
 346         tay
 347         ; Peephole regop 8 - removed redundant tya preceded by tay
 348 }
 349
 350 replace restart {
 351         tax
 352         %1 %2
 353         tax
 354 } by {
 355         ; Peephole regop 9 - removed redundant tax
 356         %1 %2
 357         tax
 358 } if notSame(%1 'stx' 'cpx' 'bne' 'beq' 'bpl' 'bmi' 'jsr' 'jmp')
 359
 360 // if same(%1 'ora' 'and' 'eor' )
 361
 362 replace restart {
 363         tay
 364         %1 %2
 365         tay
 366 } by {
 367         ; Peephole regop 10 - removed redundant tay
 368         %1 %2
 369         tay
 370 } if notSame(%1 'sty' 'cpy' 'bne' 'beq' 'bpl' 'bmi' 'jsr' 'jmp')
 371
 372 ////////////////////////////////////////////////////////
 373 // Remove redundant/unnecessry stack operations
 374 ////////////////////////////////////////////////////////
 375
 376 replace restart {
 377         pla
 378         pha
 379         lda     %1
 380 } by {
 381         ; Peephole stack 1 - removed dead pla/pha followed by lda
 382         lda     %1
 383 }
 384
 385 replace restart {
 386         pla
 387         pha
 388         %1
 389 } by {
 390         ; Peephole stack 2 - removed dead pla/pha followed by txa/tya
 391         %1
 392 }  if same(%1 'txa' 'tya')
 393
 394 replace restart {
 395         php
 396         %1 %2
 397         plp
 398 } by {
 399         ; Peephole stack 3 - removed useless php/plp around a store
 400         %1 %2
 401 }  if same(%1 'sta' 'stx' 'sty' )
 402
 403
 404 replace restart {
 405         php
 406         plp
 407 } by {
 408         ; Peephole stack 4 - removed dead php/plp
 409 }
 410
 411 ////////////////////////////////////////////////////////
 412 // Remove unnecessary ora #00
 413 ////////////////////////////////////////////////////////
 414 replace restart {
 415         ora     #0x00
 416 } by {
 417         ; Peephole or 1 - eliminated unnecessary ora #0x00
 418 } if notUsed('n' 'z')
 419
 420 replace restart {
 421         cmp     #0x00
 422 } by {
 423         ; Peephole or 2 - eliminated unnecessary cmp #0x00
 424 } if notUsed('n' 'z' 'c')
 425
 426 ////////////////////////////////////////////////////////
 427 // Remove unnecessary cmp/cpx/cpy #00
 428 ////////////////////////////////////////////////////////
 429
 430 replace restart {
 431         lda     %1
 432         cmp     #0x00
 433 } by {
 434         lda     %1
 435         ; Peephole cmp 1 - eliminated unnecessary cmp #0x00
 436 } if notUsed('c')
 437
 438 replace restart {
 439         lda     %1,%2
 440         cmp     #0x00
 441 } by {
 442         lda     %1,%2
 443         ; Peephole cmp 2 - eliminated unnecessary cmp #0x00
 444 } if notUsed('c')
 445
 446 replace restart {
 447         %1
 448         cmp     #0x00
 449 } by {
 450         %1
 451         ; Peephole cmp 3 - eliminated unnecessary cmp #0x00
 452 } if same(%1 'pla' 'txa' 'tya' ), notUsed('c')
 453
 454 replace restart {
 455         ldx     %1
 456         cpx     #0x00
 457 } by {
 458         ldx     %1
 459         ; Peephole cmp 4 - eliminated unnecessary cpx #0x00
 460 } if notUsed('c')
 461
 462 replace restart {
 463         ldy     %1
 464         cpy     #0x00
 465 } by {
 466         ldy     %1
 467         ; Peephole cmp 5 - eliminated unnecessary cpy #0x00
 468 } if notUsed('c')
 469
 470 replace restart {
 471         %1
 472         cpx     #0x00
 473 } by {
 474         %1
 475         ; Peephole cmp 6 - eliminated unnecessary cpx #0x00
 476 } if same(%1 'inx' 'dex' 'tax' ), notUsed('c')
 477
 478 replace restart {
 479         %1
 480         cpy     #0x00
 481 } by {
 482         %1
 483         ; Peephole cmp 7 - eliminated unnecessary cpy #0x00
 484 } if same(%1 'iny' 'dey' 'tay' ), notUsed('c')
 485
 486 ////////////////////////////////////////////////////////
 487 // Remove redundant stores
 488 ////////////////////////////////////////////////////////
 489
 490 replace restart {
 491         lda     %2
 492         sta     %2
 493 } by {
 494         lda     %2
 495         ; Peephole store 1 - removed redundant sta
 496 } if notVolatile(%2)
 497
 498 replace restart {
 499         lda     %2
 500         %1
 501         sta     %2
 502 } by {
 503         lda     %2
 504         %1
 505         ; Peephole store 2 - removed redundant sta
 506 } if notSame(%1 'pla' 'txa' 'tya'), notVolatile(%2)
 507
 508 replace restart {
 509         lda     %2
 510         %1      a
 511         sta     %2
 512 } by {
 513         ; Peephole store 3 - removed redundant sta
 514         %1      %2
 515         lda     %2
 516 } if same(%1 'asl' 'rol' 'ror'), notVolatile(%2)
 517
 518 replace restart {
 519         ldx     %2
 520         stx     %2
 521 } by {
 522         ldx     %2
 523         ; Peephole store 4 - removed redundant stx
 524 } if notVolatile(%2)
 525
 526 replace restart {
 527         ldx     %2
 528         %1
 529         stx     %2
 530 } by {
 531         ldx     %2
 532         %1
 533         ; Peephole store 5 - removed redundant stx
 534 } if notSame(%1 'tax' 'inx' 'dex'), notVolatile(%2)
 535
 536 replace restart {
 537         ldy     %2
 538         sty     %2
 539 } by {
 540         ldy     %2
 541         ; Peephole store 6 - removed redundant sty
 542 } if notVolatile(%2)
 543
 544 replace restart {
 545         ldy     %2
 546         %1
 547         sty     %2
 548 } by {
 549         ldy     %2
 550         %1
 551         ; Peephole store 7 - removed redundant sty
 552 } if notSame(%1 'tay' 'iny' 'dey'), notVolatile(%2)
 553
 554 ////////////////////////////////////////////////////////
 555 // Replace jmp with branch
 556 ////////////////////////////////////////////////////////
 557
 558 replace restart {
 559         bne     %1
 560         jmp     %5
 561 %1:
 562 } by {
 563         beq     %5
 564         ; Peephole branch 1 - inverted bne and eliminated jmp
 565 %1:
 566 } if labelInRange(%5), labelRefCountChange(%1 -1)
 567
 568 replace restart {
 569         beq     %1
 570         jmp     %5
 571 %1:
 572 } by {
 573         bne     %5
 574         ; Peephole branch 2 - inverted beq and eliminated jmp
 575 %1:
 576 } if labelInRange(%5), labelRefCountChange(%1 -1)
 577
 578 replace restart {
 579         bcc     %1
 580         jmp     %5
 581 %1:
 582 } by {
 583         bcs     %5
 584         ; Peephole branch 3 - inverted bcc and eliminated jmp
 585 %1:
 586 } if labelInRange(%5), labelRefCountChange(%1 -1)
 587
 588 replace restart {
 589         bcs     %1
 590         jmp     %5
 591 %1:
 592 } by {
 593         bcc     %5
 594         ; Peephole branch 4 - inverted bcs and eliminated jmp
 595 %1:
 596 } if labelInRange(%5), labelRefCountChange(%1 -1)
 597
 598 replace restart {
 599         bpl     %1
 600         jmp     %5
 601 %1:
 602 } by {
 603         bmi     %5
 604         ; Peephole branch 5 - inverted bpl and eliminated jmp
 605 %1:
 606 } if labelInRange(%5), labelRefCountChange(%1 -1)
 607
 608 replace restart {
 609         bmi     %1
 610         jmp     %5
 611 %1:
 612 } by {
 613         bpl     %5
 614         ; Peephole branch 6 - inverted bmi and eliminated jmp
 615 %1:
 616 } if labelInRange(%5), labelRefCountChange(%1 -1)
 617
 618 replace restart {
 619         bvc     %1
 620         jmp     %5
 621 %1:
 622 } by {
 623         bvs     %5
 624         ; Peephole branch 7 - inverted bvc and eliminated jmp
 625 %1:
 626 } if labelInRange(%5), labelRefCountChange(%1 -1)
 627
 628 replace restart {
 629         bvs     %1
 630         jmp     %5
 631 %1:
 632 } by {
 633         bvc     %5
 634         ; Peephole branch 8 - inverted bvs and eliminated jmp
 635 %1:
 636 } if labelInRange(%5), labelRefCountChange(%1 -1)
 637
 638 ////////////////////////////////////////////////////////
 639 // Replace branch to jmp with branch
 640 ////////////////////////////////////////////////////////
 641
 642 replace restart {
 643         %1      %5
 644 } by {
 645         ; Peephole branch 9 - replaced branch to jmp with branch
 646         %1      %6
 647 } if same(%1 'bne' 'beq' 'bcc' 'bcs' 'bvc' 'bvs' 'bpl' 'bmi'), labelIsUncondJump(%5), notSame(%5 %6), labelInRange(%6), labelRefCountChange(%5 -1), labelRefCountChange(%6 +1)
 648
 649 replace restart {
 650         jmp     %5
 651 } by {
 652         ; Peephole branch 10 - replaced jmp to jmp with jmp
 653         jmp     %6
 654 } if labelIsUncondJump(%5), notSame(%5 %6), labelRefCountChange(%5 -1), labelRefCountChange(%6 +1)
 655
 656 replace restart {
 657         jmp     %5
 658 } by {
 659         ; Peephole branch 11 - replaced jmp to rts with rts
 660         rts
 661 } if optimizeReturn(), labelIsReturnOnly(%5), labelRefCountChange(%5 -1)
 662
 663 ////////////////////////////////////////////////////////
 664 // Remove branch/jump to following label
 665 ////////////////////////////////////////////////////////
 666
 667 replace restart {
 668         %1      %2
 669 %2:
 670 } by {
 671         ; Peephole branch 12 - eliminated branch to %2
 672 %2:
 673 } if same(%1 'bne' 'beq' 'bcc' 'bcs' 'bvc' 'bvs' 'bpl' 'bmi' 'jmp' 'bra'), labelRefCountChange(%2 -1)
 674
 675 ////////////////////////////////////////////////////////
 676 // Tail call optimization
 677 ////////////////////////////////////////////////////////
 678
 679 replace restart {
 680         rts
 681 %1:
 682         rts
 683 } by {
 684     ; Peephole ret 1 - eliminated redundant rts
 685 %1:
 686         rts
 687 }
 688
 689 replace restart {
 690         jsr     %1
 691         rts
 692 } by {
 693         jmp     %1
 694         ; Peephole ret 2 - tail call optimization.
 695 } if optimizeReturn()
 696
 697 ////////////////////////////////////////////////////////
 698 // Unused label removal
 699 ////////////////////////////////////////////////////////
 700
 701 // should be one of the last peepholes
 702 replace restart {
 703 %1:
 704 } by {
 705         ; Peephole label - removed redundant label %1
 706 } if labelRefCount(%1 0)
 707