Commit | Line | Data |
---|---|---|
08b50d78 | 1 | # |
31cef89c | 2 | static char sccsid[] = "@(#)c20.c 4.3 10/17/80"; |
d9657d8c | 3 | /* char C20[] = {"@(#)c20.c 1.35 80/08/26 14:13:40"}; /* sccs ident */ |
08b50d78 BJ |
4 | /* |
5 | * C object code improver | |
6 | */ | |
7 | ||
8 | #include "c2.h" | |
9 | #include <stdio.h> | |
10 | #include <ctype.h> | |
11 | ||
12 | char _sibuf[BUFSIZ], _sobuf[BUFSIZ]; | |
13 | int ioflag; | |
d9657d8c | 14 | long isn = 2000000; |
08b50d78 BJ |
15 | struct optab *oplook(); |
16 | struct optab *getline(); | |
d9657d8c BJ |
17 | long lgensym[10] = |
18 | {100000L,200000L,300000L,400000L,500000L,600000L,700000L,800000L,900000L,1000000L}; | |
08b50d78 BJ |
19 | |
20 | struct node * | |
21 | alloc(an) | |
22 | { | |
23 | register int n; | |
24 | register char *p; | |
25 | ||
26 | n = an; | |
d9657d8c BJ |
27 | n+=sizeof(char *)-1; |
28 | n &= ~(sizeof(char *)-1); | |
08b50d78 BJ |
29 | if (lasta+n >= lastr) { |
30 | if (sbrk(2000) == -1) { | |
31 | fprintf(stderr, "Optimizer: out of space\n"); | |
32 | exit(1); | |
33 | } | |
34 | lastr += 2000; | |
35 | } | |
36 | p = lasta; | |
37 | lasta += n; | |
38 | return(p); | |
39 | } | |
40 | ||
41 | main(argc, argv) | |
42 | char **argv; | |
43 | { | |
44 | register int niter, maxiter, isend; | |
45 | int nflag,infound; | |
46 | ||
47 | nflag = 0; infound=0; argc--; argv++; | |
48 | while (argc>0) {/* get flags */ | |
49 | if (**argv=='+') debug++; | |
50 | else if (**argv=='-') { | |
51 | if ((*argv)[1]=='i') ioflag++; else nflag++; | |
52 | } else if (infound==0) { | |
53 | if (freopen(*argv, "r", stdin) ==NULL) { | |
54 | fprintf(stderr,"C2: can't find %s\n", *argv); | |
55 | exit(1); | |
56 | } | |
57 | setbuf(stdin,_sibuf); ++infound; | |
58 | } else if (freopen(*argv, "w", stdout) ==NULL) { | |
59 | fprintf(stderr,"C2: can't create %s\n", *argv); | |
60 | exit(1); | |
61 | } | |
62 | setbuf(stdout,_sobuf); | |
63 | argc--; argv++; | |
64 | } | |
65 | lasta = lastr = sbrk(2); | |
66 | opsetup(); | |
67 | lasta = firstr = lastr = alloc(0); | |
68 | maxiter = 0; | |
69 | do { | |
70 | isend = input(); | |
71 | niter = 0; | |
72 | bmove(); | |
73 | do { | |
74 | refcount(); | |
75 | do { | |
76 | iterate(); | |
77 | clearreg(); | |
78 | niter++; | |
79 | } while (nchange); | |
80 | comjump(); | |
81 | rmove(); | |
82 | } while (nchange || jumpsw()); | |
83 | addsob(); | |
84 | output(); | |
85 | if (niter > maxiter) | |
86 | maxiter = niter; | |
87 | lasta = firstr; | |
88 | } while (isend); | |
89 | if (nflag) { | |
90 | fprintf(stderr,"%d iterations\n", maxiter); | |
91 | fprintf(stderr,"%d jumps to jumps\n", nbrbr); | |
92 | fprintf(stderr,"%d inst. after jumps\n", iaftbr); | |
93 | fprintf(stderr,"%d jumps to .+1\n", njp1); | |
94 | fprintf(stderr,"%d redundant labels\n", nrlab); | |
95 | fprintf(stderr,"%d cross-jumps\n", nxjump); | |
96 | fprintf(stderr,"%d code motions\n", ncmot); | |
97 | fprintf(stderr,"%d branches reversed\n", nrevbr); | |
98 | fprintf(stderr,"%d redundant moves\n", redunm); | |
99 | fprintf(stderr,"%d simplified addresses\n", nsaddr); | |
100 | fprintf(stderr,"%d loops inverted\n", loopiv); | |
101 | fprintf(stderr,"%d redundant jumps\n", nredunj); | |
102 | fprintf(stderr,"%d common seqs before jmp's\n", ncomj); | |
103 | fprintf(stderr,"%d skips over jumps\n", nskip); | |
104 | fprintf(stderr,"%d sob's added\n", nsob); | |
105 | fprintf(stderr,"%d redundant tst's\n", nrtst); | |
106 | fprintf(stderr,"%d jump on bit\n", nbj); | |
107 | fprintf(stderr,"%d field operations\n", nfield); | |
108 | fprintf(stderr,"%dK core\n", ((unsigned)lastr+01777) >> 10); | |
109 | } | |
110 | putc('\n',stdout); | |
111 | fflush(stdout); exit(0); | |
112 | } | |
113 | ||
114 | input() | |
115 | { | |
116 | register struct node *p, *lastp; | |
117 | struct optab *op; register char *cp1; | |
118 | static struct optab F77JSW = {".long", T(JSW,1)}; | |
119 | ||
120 | lastp = &first; | |
121 | for (;;) { | |
122 | top: | |
123 | op = getline(); | |
124 | if (debug && op==0) fprintf(stderr,"? %s\n",line); | |
125 | switch (op->opcode&0377) { | |
126 | ||
127 | case LABEL: | |
128 | p = alloc(sizeof first); | |
129 | if (isdigit(line[0]) && (p->labno=locdef(line)) || | |
130 | (line[0] == 'L') && (p->labno=getnum(line+1))) { | |
131 | p->combop = LABEL; | |
d9657d8c | 132 | if (p->labno<100000L && isn<=p->labno) isn=1+p->labno; |
08b50d78 BJ |
133 | p->code = 0; |
134 | } else { | |
135 | p->combop = DLABEL; | |
136 | p->labno = 0; | |
137 | p->code = copy(line); | |
138 | } | |
139 | break; | |
140 | ||
141 | case LGEN: | |
142 | if (*curlp!='L' && !locuse(curlp)) goto std; | |
143 | op= &F77JSW; | |
144 | case JBR: | |
145 | if (op->opcode==T(JBR,RET) || op->opcode==T(JBR,RSB)) goto std; | |
146 | case CBR: | |
147 | case JMP: | |
148 | case JSW: | |
149 | case SOBGEQ: case SOBGTR: case AOBLEQ: case AOBLSS: case ACB: | |
150 | p = alloc(sizeof first); | |
151 | p->combop = op->opcode; p->code=0; cp1=curlp; | |
152 | if ((!isdigit(*cp1) || 0==(p->labno=locuse(cp1))) && | |
153 | (*cp1!='L' || 0==(p->labno = getnum(cp1+1)))) {/* jbs, etc.? */ | |
154 | while (*cp1++); while (*--cp1!=',' && cp1!=curlp); | |
155 | if (cp1==curlp || | |
156 | (!isdigit(*++cp1) || 0==(p->labno=locuse(cp1))) && | |
157 | (*cp1!='L' || 0==(p->labno=getnum(cp1+1)))) | |
158 | p->labno = 0; | |
159 | else *--cp1=0; | |
160 | p->code = copy(curlp); | |
161 | } | |
162 | if (isn<=p->labno) isn=1+p->labno; | |
163 | break; | |
164 | ||
165 | case MOVA: | |
166 | p=alloc(sizeof first); | |
167 | p->combop=op->opcode; p->code=0; cp1=curlp+1; | |
168 | if (cp1[-1]=='L' || isdigit(cp1[-1])) { | |
169 | while (*cp1++!=','); *--cp1=0; | |
170 | if (0!=(p->labno=locuse(curlp)) || | |
171 | 0!=(p->labno=getnum(curlp+1))) p->code=copy(cp1+1); | |
172 | else {*cp1=','; p->code=copy(curlp);} | |
173 | } else {p->code=copy(--cp1); p->labno=0;} | |
174 | break; | |
175 | ||
176 | case SET: | |
177 | case COMM: | |
178 | case LCOMM: | |
179 | printf("%s\n",line); goto top; | |
180 | ||
181 | case BSS: | |
182 | case DATA: | |
183 | for (;;) { | |
184 | printf("%s%c",line,(op->opcode==LABEL ? ':' : '\n')); | |
185 | if (op->opcode==TEXT) goto top; | |
186 | if (END==(op=getline())->opcode) {/* dangling .data is bad for you */ | |
187 | printf(".text\n"); | |
188 | break; | |
189 | } | |
190 | } | |
191 | ||
192 | std: | |
193 | default: | |
194 | p = alloc(sizeof first); | |
195 | p->combop = op->opcode; | |
196 | p->labno = 0; | |
197 | p->code = copy(curlp); | |
198 | break; | |
199 | ||
200 | } | |
201 | p->forw = 0; | |
202 | p->back = lastp; | |
203 | p->pop = op; | |
204 | lastp->forw = p; | |
205 | lastp = p; | |
206 | p->ref = 0; | |
207 | if (p->op==CASE) { | |
208 | char *lp; int ncase; | |
209 | lp=curlp; while (*lp++); while (*--lp!='$'); ncase=getnum(lp+1); | |
210 | if (LABEL!=(getline())->opcode) abort(-2); | |
211 | do { | |
212 | if (WGEN!=(getline())->opcode) abort(-3); | |
213 | p = alloc(sizeof first); p->combop = JSW; p->code = 0; | |
214 | lp=curlp; while(*lp++!='-'); *--lp=0; p->labno=getnum(curlp+1); | |
215 | if (isn<=p->labno) isn=1+p->labno; | |
216 | p->forw = 0; p->back = lastp; lastp->forw = p; lastp = p; | |
217 | p->ref = 0; p->pop=0; | |
218 | } while (--ncase>=0); | |
219 | } | |
220 | if (op->opcode==EROU) | |
221 | return(1); | |
222 | if (op->opcode==END) | |
223 | return(0); | |
224 | } | |
225 | } | |
226 | ||
227 | struct optab * | |
228 | getline() | |
229 | { | |
230 | register char *lp; | |
231 | register c; | |
232 | static struct optab OPLABEL={"",LABEL}; | |
233 | static struct optab OPEND={"",END}; | |
234 | ||
235 | lp = line; | |
236 | while (EOF!=(c=getchar()) && isspace(c)); | |
237 | while (EOF!=c) { | |
238 | if (c==':') { | |
239 | *lp++ = 0; | |
240 | return(&OPLABEL); | |
241 | } | |
242 | if (c=='\n') { | |
243 | *lp++ = 0; | |
244 | return(oplook()); | |
245 | } | |
246 | *lp++ = c; | |
247 | c = getchar(); | |
248 | } | |
249 | *lp++ = 0; | |
250 | return(&OPEND); | |
251 | } | |
252 | ||
253 | long | |
254 | getnum(p) | |
255 | register char *p; | |
256 | { | |
257 | register c; int neg; register long n; | |
258 | ||
259 | n = 0; neg=0; if (*p=='-') {++neg; ++p;} | |
260 | while (isdigit(c = *p++)) { | |
261 | c -= '0'; n *= 10; if (neg) n -= c; else n += c; | |
262 | } | |
263 | if (*--p != 0) | |
264 | return(0); | |
265 | return(n); | |
266 | } | |
267 | ||
268 | locuse(p) | |
269 | register char *p; | |
270 | { | |
271 | register c; int neg; register long n; | |
272 | ||
273 | if (!isdigit(p[0]) || p[1] != 'f' && p[1] != 'b' || p[2]) return(0); | |
274 | return (lgensym[p[0] - '0'] - (p[1] == 'b')); | |
275 | } | |
276 | ||
277 | locdef(p) | |
278 | register char *p; | |
279 | { | |
280 | ||
281 | if (!isdigit(p[0]) || p[1]) return(0); | |
282 | return (lgensym[p[0] - '0']++); | |
283 | } | |
284 | ||
285 | output() | |
286 | { | |
287 | register struct node *t; | |
288 | int casebas; | |
289 | ||
290 | t = &first; | |
291 | while (t = t->forw) switch (t->op) { | |
292 | ||
293 | case END: | |
294 | fflush(stdout); | |
295 | return; | |
296 | ||
297 | case LABEL: | |
298 | printf("L%d:", t->labno); | |
299 | continue; | |
300 | ||
301 | case DLABEL: | |
302 | printf("%s:", t->code); | |
303 | continue; | |
304 | ||
305 | case CASE: | |
306 | casebas=0; | |
307 | ||
308 | default: std: | |
309 | if (t->pop==0) {/* must find it */ | |
310 | register struct optab *p; | |
311 | for (p=optab; p->opstring[0]; ++p) | |
312 | if (p->opcode==t->combop) {t->pop=p; break;} | |
313 | } | |
314 | printf("%s", t->pop->opstring); | |
315 | if (t->code) printf("\t%s", t->code); | |
316 | if (t->labno!=0) printf("%cL%d\n", | |
317 | (t->code ? ',' : '\t'), | |
318 | t->labno); | |
319 | else printf("\n"); | |
320 | continue; | |
321 | ||
322 | case MOVA: | |
323 | if (t->labno==0) goto std; | |
324 | printf("mova%c\tL%d,%s\n","bwlq"[t->subop-BYTE],t->labno,t->code); | |
325 | continue; | |
326 | ||
327 | case JSW: | |
328 | if (t->subop!=0) {/* F77JSW */ | |
329 | printf(".long\tL%d\n",t->labno); continue; | |
330 | } | |
331 | if (casebas==0) printf("L%d:\n",casebas=isn++); | |
332 | printf(".word L%d-L%d\n", t->labno, casebas); | |
333 | continue; | |
334 | ||
335 | } | |
336 | } | |
337 | ||
338 | char * | |
339 | copy(ap) | |
340 | char *ap; | |
341 | { | |
342 | register char *p, *np; | |
343 | char *onp; | |
344 | register n; | |
345 | int na; | |
346 | ||
347 | na = nargs(); | |
348 | p = ap; | |
349 | n = 0; | |
350 | if (*p==0) | |
351 | return(0); | |
352 | do | |
353 | n++; | |
354 | while (*p++); | |
355 | if (na>1) { | |
356 | p = (&ap)[1]; | |
357 | while (*p++) | |
358 | n++; | |
359 | } | |
360 | onp = np = alloc(n); | |
361 | p = ap; | |
362 | while (*np++ = *p++); | |
363 | if (na>1) { | |
364 | p = (&ap)[1]; | |
365 | np--; | |
366 | while (*np++ = *p++); | |
367 | } | |
368 | return(onp); | |
369 | } | |
370 | ||
371 | #define OPHS 560 | |
372 | struct optab *ophash[OPHS]; | |
373 | ||
374 | opsetup() | |
375 | { | |
376 | register struct optab *optp, **ophp; | |
377 | register int i,t; | |
378 | ||
379 | for(i=NREG+5;--i>=0;) regs[i]=alloc(20); | |
380 | for (optp = optab; optp->opstring[0]; optp++) { | |
381 | t=7; i=0; while (--t>=0) i+= i+optp->opstring[t]; | |
382 | ophp = &ophash[i % OPHS]; | |
383 | while (*ophp++) { | |
384 | /* fprintf(stderr,"\ncollision: %d %s %s", | |
385 | /* ophp-1-ophash,optp->opstring,(*(ophp-1))->opstring); | |
386 | */ | |
387 | if (ophp > &ophash[OPHS]) | |
388 | ophp = ophash; | |
389 | } | |
390 | *--ophp = optp; | |
391 | } | |
392 | } | |
393 | ||
394 | struct optab * | |
395 | oplook() | |
396 | { | |
397 | register struct optab *optp,**ophp; | |
398 | register char *p,*p2; | |
399 | register int t; | |
400 | char tempop[20]; | |
401 | static struct optab OPNULL={"",0}; | |
402 | ||
403 | for (p=line, p2=tempop; *p && !isspace(*p); *p2++= *p++); *p2=0; p2=p; | |
404 | while (isspace(*p2)) ++p2; curlp=p2; | |
405 | t=0; while(--p>=line) t += t+*p; ophp = &ophash[t % OPHS]; | |
406 | while (optp = *ophp) { | |
407 | if (equstr(tempop,optp->opstring)) return(optp); | |
408 | if ((++ophp) >= &ophash[OPHS]) ophp = ophash; | |
409 | } | |
410 | curlp = line; | |
411 | return(&OPNULL); | |
412 | } | |
413 | ||
414 | refcount() | |
415 | { | |
416 | register struct node *p, *lp; | |
417 | struct node *labhash[LABHS]; | |
418 | register struct node **hp; | |
419 | ||
420 | for (hp = labhash; hp < &labhash[LABHS];) | |
421 | *hp++ = 0; | |
422 | for (p = first.forw; p!=0; p = p->forw) | |
423 | if (p->op==LABEL) { | |
424 | labhash[p->labno % LABHS] = p; | |
425 | p->refc = 0; | |
426 | } | |
427 | for (p = first.forw; p!=0; p = p->forw) { | |
428 | if (p->combop==JBR || p->op==CBR || p->op==JSW || p->op==JMP | |
429 | || p->op==SOBGEQ || p->op==SOBGTR || p->op==AOBLEQ || p->op==AOBLSS | |
430 | || p->op==ACB || (p->op==MOVA && p->labno!=0)) { | |
431 | p->ref = 0; | |
432 | lp = labhash[p->labno % LABHS]; | |
433 | if (lp==0 || p->labno!=lp->labno) | |
434 | for (lp = first.forw; lp!=0; lp = lp->forw) { | |
435 | if (lp->op==LABEL && p->labno==lp->labno) | |
436 | break; | |
437 | } | |
438 | if (lp) { | |
439 | hp = nonlab(lp)->back; | |
440 | if (hp!=lp) { | |
441 | p->labno = hp->labno; | |
442 | lp = hp; | |
443 | } | |
444 | p->ref = lp; | |
445 | lp->refc++; | |
446 | } | |
447 | } | |
448 | } | |
449 | for (p = first.forw; p!=0; p = p->forw) | |
450 | if (p->op==LABEL && p->refc==0 | |
451 | && (lp = nonlab(p))->op && lp->op!=JSW) | |
452 | decref(p); | |
453 | } | |
454 | ||
455 | iterate() | |
456 | { | |
457 | register struct node *p, *rp, *p1; | |
458 | ||
459 | nchange = 0; | |
460 | for (p = first.forw; p!=0; p = p->forw) { | |
461 | if ((p->op==JBR||p->op==CBR||p->op==JSW) && p->ref) { | |
462 | rp = nonlab(p->ref); | |
463 | if (rp->op==JBR && rp->labno && p->labno!=rp->labno) { | |
464 | nbrbr++; | |
465 | p->labno = rp->labno; | |
466 | decref(p->ref); | |
467 | rp->ref->refc++; | |
468 | p->ref = rp->ref; | |
469 | nchange++; | |
470 | } | |
471 | } | |
472 | #ifndef COPYCODE | |
473 | if (p->op==CBR && (p1 = p->forw)->combop==JBR) {/* combop: RET problems */ | |
474 | #else | |
475 | if (p->op==CBR && (p1 = p->forw)->combop==JBR && | |
476 | p->ref) {/* combop: RET problems */ | |
477 | #endif | |
478 | rp = p->ref; | |
479 | do | |
480 | rp = rp->back; | |
481 | while (rp->op==LABEL); | |
482 | if (rp==p1) { | |
483 | decref(p->ref); | |
484 | p->ref = p1->ref; | |
485 | p->labno = p1->labno; | |
486 | #ifdef COPYCODE | |
487 | if (p->labno == 0) | |
488 | p->code = p1->code; | |
489 | #endif | |
490 | p1->forw->back = p; | |
491 | p->forw = p1->forw; | |
492 | p->subop = revbr[p->subop]; | |
493 | p->pop=0; | |
494 | nchange++; | |
495 | nskip++; | |
496 | } | |
497 | } | |
498 | if (p->op==JBR || p->op==JMP) { | |
499 | while (p->forw && p->forw->op!=LABEL && p->forw->op!=DLABEL | |
500 | && p->forw->op!=EROU && p->forw->op!=END | |
501 | && p->forw->op!=ALIGN | |
502 | && p->forw->op!=0 && p->forw->op!=DATA) { | |
503 | nchange++; | |
504 | iaftbr++; | |
505 | if (p->forw->ref) | |
506 | decref(p->forw->ref); | |
507 | p->forw = p->forw->forw; | |
508 | p->forw->back = p; | |
509 | } | |
510 | rp = p->forw; | |
511 | while (rp && rp->op==LABEL) { | |
512 | if (p->ref == rp) { | |
513 | p->back->forw = p->forw; | |
514 | p->forw->back = p->back; | |
515 | p = p->back; | |
516 | decref(rp); | |
517 | nchange++; | |
518 | njp1++; | |
519 | break; | |
520 | } | |
521 | rp = rp->forw; | |
522 | } | |
523 | xjump(p); | |
524 | p = codemove(p); | |
525 | } | |
526 | } | |
527 | } | |
528 | ||
529 | xjump(p1) | |
530 | register struct node *p1; | |
531 | { | |
532 | register struct node *p2, *p3; | |
533 | int nxj; | |
534 | ||
535 | nxj = 0; | |
536 | if ((p2 = p1->ref)==0) | |
537 | return(0); | |
538 | for (;;) { | |
539 | while ((p1 = p1->back) && p1->op==LABEL); | |
540 | while ((p2 = p2->back) && p2->op==LABEL); | |
541 | if (!equop(p1, p2) || p1==p2) | |
542 | return(nxj); | |
543 | p3 = insertl(p2); | |
544 | p1->combop = JBR; | |
545 | p1->pop=0; | |
546 | p1->ref = p3; | |
547 | p1->labno = p3->labno; | |
548 | p1->code = 0; | |
549 | nxj++; | |
550 | nxjump++; | |
551 | nchange++; | |
552 | } | |
553 | } | |
554 | ||
555 | struct node * | |
556 | insertl(op) | |
557 | register struct node *op; | |
558 | { | |
559 | register struct node *lp; | |
560 | ||
561 | if (op->op == LABEL) { | |
562 | op->refc++; | |
563 | return(op); | |
564 | } | |
565 | if (op->back->op == LABEL) { | |
566 | op = op->back; | |
567 | op->refc++; | |
568 | return(op); | |
569 | } | |
570 | lp = alloc(sizeof first); | |
571 | lp->combop = LABEL; | |
572 | lp->labno = isn++; | |
573 | lp->ref = 0; | |
574 | lp->code = 0; | |
575 | lp->refc = 1; | |
576 | lp->back = op->back; | |
577 | lp->forw = op; | |
578 | op->back->forw = lp; | |
579 | op->back = lp; | |
580 | return(lp); | |
581 | } | |
582 | ||
583 | struct node * | |
584 | codemove(ap) | |
585 | struct node *ap; | |
586 | { | |
587 | register struct node *p1, *p2, *p3; | |
588 | struct node *t, *tl; | |
589 | int n; | |
590 | ||
591 | p1 = ap; | |
592 | /* last clause to avoid infinite loop on partial compiler droppings: | |
593 | L183: jbr L179 | |
594 | L191: jbr L179 | |
595 | casel r0,$0,$1 | |
596 | L193: .word L183-L193 | |
597 | .word L191-L193 | |
598 | L179: ret | |
599 | */ | |
600 | if (p1->op!=JBR || (p2 = p1->ref)==0 || p2==p1->forw) | |
601 | return(p1); | |
602 | while (p2->op == LABEL) | |
603 | if ((p2 = p2->back) == 0) | |
604 | return(p1); | |
605 | if (p2->op!=JBR && p2->op!=JMP) | |
606 | goto ivloop; | |
607 | p2 = p2->forw; | |
608 | p3 = p1->ref; | |
609 | while (p3) { | |
610 | if (p3->op==JBR || p3->op==JMP) { | |
611 | if (p1==p3) | |
612 | return(p1); | |
613 | ncmot++; | |
614 | nchange++; | |
615 | p1->back->forw = p2; | |
616 | p1->forw->back = p3; | |
617 | p2->back->forw = p3->forw; | |
618 | p3->forw->back = p2->back; | |
619 | p2->back = p1->back; | |
620 | p3->forw = p1->forw; | |
621 | decref(p1->ref); | |
622 | return(p2); | |
623 | } else | |
624 | p3 = p3->forw; | |
625 | } | |
626 | return(p1); | |
627 | ivloop: | |
628 | if (p1->forw->op!=LABEL) | |
629 | return(p1); | |
630 | p3 = p2 = p2->forw; | |
631 | n = 16; | |
632 | do { | |
633 | if ((p3 = p3->forw) == 0 || p3==p1 || --n==0) | |
634 | return(p1); | |
635 | } while (p3->op!=CBR || p3->labno!=p1->forw->labno); | |
636 | do | |
637 | if ((p1 = p1->back) == 0) | |
638 | return(ap); | |
639 | while (p1!=p3); | |
640 | p1 = ap; | |
641 | tl = insertl(p1); | |
642 | p3->subop = revbr[p3->subop]; | |
643 | p3->pop=0; | |
644 | decref(p3->ref); | |
645 | p2->back->forw = p1; | |
646 | p3->forw->back = p1; | |
647 | p1->back->forw = p2; | |
648 | p1->forw->back = p3; | |
649 | t = p1->back; | |
650 | p1->back = p2->back; | |
651 | p2->back = t; | |
652 | t = p1->forw; | |
653 | p1->forw = p3->forw; | |
654 | p3->forw = t; | |
655 | p2 = insertl(p1->forw); | |
656 | p3->labno = p2->labno; | |
657 | #ifdef COPYCODE | |
658 | if (p3->labno == 0) | |
659 | p3->code = p2->code; | |
660 | #endif | |
661 | p3->ref = p2; | |
662 | decref(tl); | |
663 | if (tl->refc<=0) | |
664 | nrlab--; | |
665 | loopiv++; | |
666 | nchange++; | |
667 | return(p3); | |
668 | } | |
669 | ||
670 | comjump() | |
671 | { | |
672 | register struct node *p1, *p2, *p3; | |
673 | ||
674 | for (p1 = first.forw; p1!=0; p1 = p1->forw) | |
675 | if (p1->op==JBR && ((p2 = p1->ref) && p2->refc > 1 | |
676 | || p1->subop==RET || p1->subop==RSB)) | |
677 | for (p3 = p1->forw; p3!=0; p3 = p3->forw) | |
678 | if (p3->op==JBR && p3->ref == p2) | |
679 | backjmp(p1, p3); | |
680 | } | |
681 | ||
682 | backjmp(ap1, ap2) | |
683 | struct node *ap1, *ap2; | |
684 | { | |
685 | register struct node *p1, *p2, *p3; | |
686 | ||
687 | p1 = ap1; | |
688 | p2 = ap2; | |
689 | for(;;) { | |
690 | while ((p1 = p1->back) && p1->op==LABEL); | |
691 | p2 = p2->back; | |
692 | if (equop(p1, p2)) { | |
693 | p3 = insertl(p1); | |
694 | p2->back->forw = p2->forw; | |
695 | p2->forw->back = p2->back; | |
696 | p2 = p2->forw; | |
697 | decref(p2->ref); | |
698 | p2->combop = JBR; /* to handle RET */ | |
699 | p2->pop=0; | |
700 | p2->labno = p3->labno; | |
701 | #ifdef COPYCODE | |
702 | p2->code = 0; | |
703 | #endif | |
704 | p2->ref = p3; | |
705 | nchange++; | |
706 | ncomj++; | |
707 | } else | |
708 | return; | |
709 | } | |
710 | } |