xref: /csrg-svn/old/pcc/ccom.vax/local2.c (revision 32943)
1 # ifndef lint
2 static char *sccsid ="@(#)local2.c	1.37 (Berkeley) 12/11/87";
3 # endif
4 
5 # include "pass2.h"
6 # include <ctype.h>
7 
8 # define putstr(s)	fputs((s), stdout)
9 
10 # ifdef FORT
11 int ftlab1, ftlab2;
12 # endif
13 /* a lot of the machine dependent parts of the second pass */
14 
15 # define BITMASK(n) ((1L<<n)-1)
16 
17 /*ARGSUSED*/
18 where(c){
19 	fprintf( stderr, "%s, line %d: ", filename, lineno );
20 	}
21 
22 lineid( l, fn ) char *fn; {
23 	/* identify line l and file fn */
24 	printf( "#	line %d, file %s\n", l, fn );
25 	}
26 
27 
28 eobl2(){
29 	register OFFSZ spoff;	/* offset from stack pointer */
30 #ifndef FORT
31 	extern int ftlab1, ftlab2;
32 #endif
33 
34 	spoff = maxoff;
35 	if( spoff >= AUTOINIT ) spoff -= AUTOINIT;
36 	spoff /= SZCHAR;
37 	SETOFF(spoff,4);
38 #ifdef FORT
39 #ifndef FLEXNAMES
40 	printf( "	.set	.F%d,%ld\n", ftnno, spoff );
41 #else
42 	/* SHOULD BE L%d ... ftnno but must change pc/f77 */
43 	printf( "	.set	LF%d,%ld\n", ftnno, spoff );
44 #endif
45 #else
46 	printf( "L%d:\n", ftlab1);
47 	if( spoff!=0 )
48 		if( spoff < 64 )
49 			printf( "	subl2	$%ld,sp\n", spoff);
50 		else
51 			printf( "	movab	-%ld(sp),sp\n", spoff);
52 	printf( "	jbr 	L%d\n", ftlab2);
53 #endif
54 	maxargs = -1;
55 	}
56 
57 struct hoptab { int opmask; char * opstring; } ioptab[] = {
58 
59 	PLUS,	"add",
60 	MINUS,	"sub",
61 	MUL,	"mul",
62 	DIV,	"div",
63 	OR,	"bis",
64 	ER,	"xor",
65 	AND,	"bic",
66 	-1, ""    };
67 
68 hopcode( f, o ){
69 	/* output the appropriate string from the above table */
70 
71 	register struct hoptab *q;
72 
73 	if(asgop(o))
74 		o = NOASG o;
75 	for( q = ioptab;  q->opmask>=0; ++q ){
76 		if( q->opmask == o ){
77 			printf( "%s%c", q->opstring, tolower(f));
78 			return;
79 			}
80 		}
81 	cerror( "no hoptab for %s", opst[o] );
82 	}
83 
84 char *
85 rnames[] = {  /* keyed to register number tokens */
86 
87 	"r0", "r1",
88 	"r2", "r3", "r4", "r5",
89 	"r6", "r7", "r8", "r9", "r10", "r11",
90 	"ap", "fp", "sp", "pc",
91 	};
92 
93 int rstatus[] = {
94 	SAREG|STAREG, SAREG|STAREG,
95 	SAREG|STAREG, SAREG|STAREG, SAREG|STAREG, SAREG|STAREG,
96 	SAREG, SAREG, SAREG, SAREG, SAREG, SAREG,
97 	SAREG, SAREG, SAREG, SAREG,
98 	};
99 
100 tlen(p) NODE *p;
101 {
102 	switch(p->in.type) {
103 		case CHAR:
104 		case UCHAR:
105 			return(1);
106 
107 		case SHORT:
108 		case USHORT:
109 			return(SZSHORT/SZCHAR);
110 
111 		case DOUBLE:
112 			return(SZDOUBLE/SZCHAR);
113 
114 		default:
115 			return(SZINT/SZCHAR);
116 		}
117 }
118 
119 mixtypes(p, q) NODE *p, *q;
120 {
121 	register TWORD tp, tq;
122 
123 	tp = p->in.type;
124 	tq = q->in.type;
125 
126 	return( (tp==FLOAT || tp==DOUBLE) !=
127 		(tq==FLOAT || tq==DOUBLE) );
128 }
129 
130 prtype(n) NODE *n;
131 {
132 	switch (n->in.type)
133 		{
134 
135 		case DOUBLE:
136 			putchar('d');
137 			return;
138 
139 		case FLOAT:
140 			putchar('f');
141 			return;
142 
143 		case LONG:
144 		case ULONG:
145 		case INT:
146 		case UNSIGNED:
147 			putchar('l');
148 			return;
149 
150 		case SHORT:
151 		case USHORT:
152 			putchar('w');
153 			return;
154 
155 		case CHAR:
156 		case UCHAR:
157 			putchar('b');
158 			return;
159 
160 		default:
161 			if ( !ISPTR( n->in.type ) ) cerror("zzzcode- bad type");
162 			else {
163 				putchar('l');
164 				return;
165 				}
166 		}
167 }
168 
169 zzzcode( p, c ) register NODE *p; {
170 	register int m;
171 	int val;
172 	switch( c ){
173 
174 	case 'N':  /* logical ops, turned into 0-1 */
175 		/* use register given by register 1 */
176 		cbgen( 0, m=getlab(), 'I' );
177 		deflab( p->bn.label );
178 		printf( "	clrl	%s\n", rnames[getlr( p, '1' )->tn.rval] );
179 		deflab( m );
180 		return;
181 
182 	case 'P':
183 		cbgen( p->in.op, p->bn.label, c );
184 		return;
185 
186 	case 'A':
187 	case 'V':
188 		sconv( p, c == 'V' );
189 		return;
190 
191 	case 'G':	/* i *= f; asgops with int lhs and float rhs */
192 		{
193 		register NODE *l, *r, *s;
194 		int rt;
195 
196 		l = p->in.left;
197 		r = p->in.right;
198 		s = talloc();
199 		rt = r->in.type;
200 
201 		s->in.op = SCONV;
202 		s->in.left = l;
203 		s->in.type = rt;
204 		zzzcode(s, 'A');
205 		putstr("\n\t");
206 
207 		hopcode(rt == FLOAT ? 'F' : 'D', p->in.op);
208 		putstr("2\t");
209 		adrput(r);
210 		putchar(',');
211 		adrput(resc);
212 		putstr("\n\t");
213 
214 		s->in.op = ASSIGN;
215 		s->in.left = l;
216 		s->in.right = resc;
217 		s->in.type = l->in.type;
218 		zzzcode(s, 'A');
219 
220 		s->in.op = FREE;
221 		return;
222 		}
223 
224 	case 'J':	/* unsigned DIV/MOD with constant divisors */
225 		{
226 		register int ck = INAREG;
227 		int label1, label2;
228 
229 		/* case constant <= 1 is handled by optim() in pass 1 */
230 		/* case constant < 0x80000000 is handled in table */
231 		switch( p->in.op ) {
232 		/* case DIV: handled in optim2() */
233 		case MOD:
234 			if( p->in.left->in.op == REG &&
235 			    p->in.left->tn.rval == resc->tn.rval )
236 				goto asgmod;
237 			label1 = getlab();
238 			expand(p, ck, "movl\tAL,A1\n\tcmpl\tA1,AR\n");
239 			printf("\tjlssu\tL%d\n", label1);
240 			expand(p, ck, "\tsubl2\tAR,A1\n");
241 			printf("L%d:", label1);
242 			break;
243 		case ASG DIV:
244 			label1 = getlab();
245 			label2 = getlab();
246 			expand(p, ck, "cmpl\tAL,AR\n");
247 			printf("\tjgequ\tL%d\n", label1);
248 			expand(p, ck, "\tmovl\t$1,AL\n");
249 			printf("\tjbr\tL%d\nL%d:\n", label2, label1);
250 			expand(p, ck, "\tclrl\tAL\n");
251 			printf("L%d:", label2);
252 			break;
253 		case ASG MOD:
254 		asgmod:
255 			label1 = getlab();
256 			expand(p, ck, "cmpl\tAL,AR\n");
257 			printf("\tjlssu\tL%d\n", label1);
258 			expand(p, ck, "\tsubl2\tAR,AL\n");
259 			printf("L%d:", label1);
260 			break;
261 			}
262 		return;
263 		}
264 
265 	case 'B':	/* get oreg value in temp register for left shift */
266 		{
267 		register NODE *r;
268 		if (xdebug) eprint(p, 0, &val, &val);
269 		r = p->in.right;
270 		if( tlen(r) == SZINT/SZCHAR && r->in.type != FLOAT )
271 			putstr("movl");
272 		else {
273 			putstr(ISUNSIGNED(r->in.type) ? "movz" : "cvt");
274 			prtype(r);
275 			putchar('l');
276 			}
277 		return;
278 		}
279 
280 	case 'C':	/* num words pushed on arg stack */
281 		{
282 		extern int gc_numbytes;
283 		extern int xdebug;
284 
285 		if (xdebug) printf("->%d<-",gc_numbytes);
286 
287 		printf("$%d", gc_numbytes/(SZLONG/SZCHAR) );
288 		return;
289 		}
290 
291 	case 'D':	/* INCR and DECR */
292 		zzzcode(p->in.left, 'A');
293 		putchar('\n');
294 		putchar('\t');
295 
296 	case 'E':	/* INCR and DECR, FOREFF */
297 		if (p->in.right->in.op == ICON && p->in.right->tn.lval == 1)
298 			{
299 			putstr(p->in.op == INCR ? "inc" : "dec");
300 			prtype(p->in.left);
301 			putchar('\t');
302 			adrput(p->in.left);
303 			return;
304 			}
305 		putstr(p->in.op == INCR ? "add" : "sub");
306 		prtype(p->in.left);
307 		putchar('2');
308 		putchar('\t');
309 		adrput(p->in.right);
310 		putchar(',');
311 		adrput(p->in.left);
312 		return;
313 
314 	case 'F':	/* register type of right operand */
315 		{
316 		register NODE *n;
317 		extern int xdebug;
318 		register int ty;
319 
320 		n = getlr( p, 'R' );
321 		ty = n->in.type;
322 
323 		if (xdebug) printf("->%d<-", ty);
324 
325 		if ( ty==DOUBLE) putchar('d');
326 		else if ( ty==FLOAT ) putchar('f');
327 		else putchar('l');
328 		return;
329 		}
330 
331 	case 'L':	/* type of left operand */
332 	case 'R':	/* type of right operand */
333 		{
334 		register NODE *n;
335 		extern int xdebug;
336 
337 		n = getlr( p, c );
338 		if (xdebug) printf("->%d<-", n->in.type);
339 
340 		prtype(n);
341 		return;
342 		}
343 
344 	case 'Z':	/* AND for CC with ICON -- lval is complemented */
345 		{
346 		register NODE *l, *r;
347 
348 		l = getlr( p, 'L' );
349 		r = getlr( p, 'R' );
350 		m = (1 << tlen(l) * SZCHAR) - 1;
351 		r->tn.lval = ~r->tn.lval;
352 		if( (l->in.type == CHAR || l->in.type == SHORT) &&
353 		    (r->tn.lval & ~m) ) {
354 			putstr("cvt");
355 			prtype(l);
356 			putstr("l\t");
357 			adrput(l);
358 			putchar(',');
359 			adrput(resc);
360 			putstr("\n\t");
361 			resc->tn.type = INT;
362 			l = resc;
363 			}
364 		else if( l->in.type == UCHAR || l->in.type == USHORT )
365 			/* remove trash left over from complementing */
366 			r->tn.lval &= m;
367 		putstr("bit");
368 		prtype(l);
369 		printf("\t$%ld", r->tn.lval);
370 		putchar(',');
371 		adrput(l);
372 		return;
373 		}
374 
375 	case 'U':	/* 32 - n, for unsigned right shifts */
376 		printf("$%d", 32 - p->in.right->tn.lval );
377 		return;
378 
379 	case 'T':	/* rounded structure length for arguments */
380 		{
381 		int size;
382 
383 		size = p->stn.stsize;
384 		SETOFF( size, 4);
385 		printf("$%d", size);
386 		return;
387 		}
388 
389 	case 'S':  /* structure assignment */
390 		stasg(p);
391 		break;
392 
393 	default:
394 		cerror( "illegal zzzcode" );
395 		}
396 	}
397 
398 stasg(p)
399 	register NODE *p;
400 {
401 	register NODE *l, *r;
402 	register size;
403 
404 	if( p->in.op == STASG ){
405 		l = p->in.left;
406 		r = p->in.right;
407 
408 		}
409 	else if( p->in.op == STARG ){  /* store an arg into a temporary */
410 		r = p->in.left;
411 		}
412 	else cerror( "STASG bad" );
413 
414 	if( r->in.op == ICON ) r->in.op = NAME;
415 	else if( r->in.op == REG ) r->in.op = OREG;
416 	else if( r->in.op != OREG ) cerror( "STASG-r" );
417 
418 	size = p->stn.stsize;
419 
420 	if( size <= 0 || size > 65535 )
421 		cerror("structure size <0=0 or >65535");
422 
423 	switch(size) {
424 		case 1:
425 			putstr("	movb	");
426 			break;
427 		case 2:
428 			putstr("	movw	");
429 			break;
430 		case 4:
431 			putstr("	movl	");
432 			break;
433 		case 8:
434 			putstr("	movq	");
435 			break;
436 		default:
437 			printf("	movc3	$%d,", size);
438 			break;
439 	}
440 	adrput(r);
441 	if( p->in.op == STASG ){
442 		putchar(',');
443 		adrput(l);
444 		putchar('\n');
445 		}
446 	else
447 		putstr(",(sp)\n");
448 
449 	if( r->in.op == NAME ) r->in.op = ICON;
450 	else if( r->in.op == OREG ) r->in.op = REG;
451 	}
452 
453 NODE *makearg( ty ) int ty; {
454 	register NODE *p, *q;
455 
456 	/* build a -(sp) operand */
457 	p = talloc();
458 	p->in.op = REG;
459 	/* the type needn't be right, just consistent */
460 	p->in.type = INCREF(ty);
461 	p->tn.rval = SP;
462 	p->tn.lval = 0;
463 	q = talloc();
464 	q->in.op = ASG MINUS;
465 	q->in.type = INCREF(ty);
466 	q->in.left = p;
467 	p = talloc();
468 	p->in.op = ICON;
469 	p->in.type = INT;
470 	p->tn.name = "";
471 	/* size of floating argument is always 2 */
472 	p->tn.lval = (1 + (ty == FLOAT || ty == DOUBLE)) * (SZINT/SZCHAR);
473 	q->in.right = p;
474 	p = talloc();
475 	p->in.op = UNARY MUL;
476 	p->in.left = q;
477 	return( p );
478 	}
479 
480 sconv( p, forarg ) register NODE *p; {
481 	register NODE *l, *r;
482 	int m, val;
483 
484 	if (xdebug) eprint(p, 0, &val, &val);
485 	r = getlr(p, 'R');
486 	if (p->in.op == ASSIGN)
487 		l = getlr(p, 'L');
488 	else if (p->in.op == SCONV) {
489 		m = r->in.type;
490 		if (forarg)
491 			l = makearg( m );
492 		else
493 			l = resc;
494 		l->in.type = m;
495 		r = getlr(p, 'L');
496 		}
497 	else {		/* OPLTYPE */
498 		m = (r->in.type==FLOAT || r->in.type==DOUBLE ? r->in.type : INT);
499 		if (forarg)
500 			l = makearg( m );
501 		else
502 			l = resc;
503 		l->in.type = m;
504 		}
505 	if (r->in.op == ICON)
506 		if (r->in.name[0] == '\0') {
507 			if (r->tn.lval == 0 &&
508 			    (r->in.type == DOUBLE || r->in.type == FLOAT ||
509 			    !forarg)) {
510 				if (r->in.type == FLOAT)
511 					r->in.type = DOUBLE;
512 				putstr("clr");
513 				prtype(l);
514 				putchar('\t');
515 				adrput(l);
516 				goto cleanup;
517 				}
518 			if (r->tn.lval < 0 && r->tn.lval >= -63) {
519 				putstr("mneg");
520 				prtype(l);
521 				r->tn.lval = -r->tn.lval;
522 				goto ops;
523 				}
524 			if (r->tn.lval < 0)
525 				r->in.type = r->tn.lval >= -128 ? CHAR
526 					: (r->tn.lval >= -32768 ? SHORT
527 					: INT);
528 			else if (l->in.type == FLOAT ||
529 			    l->in.type == DOUBLE)
530 				r->in.type = r->tn.lval <= 63 ? INT
531 					: (r->tn.lval <= 127 ? CHAR
532 					: (r->tn.lval <= 32767 ? SHORT
533 					: INT));
534 			else
535 				r->in.type = r->tn.lval <= 63 ? INT
536 					: (r->tn.lval <= 127 ? CHAR
537 					: (r->tn.lval <= 255 ? UCHAR
538 					: (r->tn.lval <= 32767 ? SHORT
539 					: (r->tn.lval <= 65535 ? USHORT
540 					: INT))));
541 			if (forarg && r->in.type == INT) {
542 				putstr("pushl\t");
543 				adrput(r);
544 				goto cleanup;
545 				}
546 			}
547 		else {
548 			if (forarg && tlen(r) == SZINT/SZCHAR) {
549 				putstr("pushl\t");
550 				adrput(r);
551 				goto cleanup;
552 				}
553 			putstr("moval\t");
554 			acon(r);
555 			putchar(',');
556 			adrput(l);
557 			goto cleanup;
558 			}
559 
560 	if (p->in.op == SCONV &&
561 	    !(l->in.type == FLOAT || l->in.type == DOUBLE) &&
562 	    !mixtypes(l, r)) {
563 		/*
564 		 * Because registers must always contain objects
565 		 * of the same width as INTs, we may have to
566 		 * perform two conversions to get an INT.  Can
567 		 * the conversions be collapsed into one?
568 		 */
569 		if (m = collapsible(l, r))
570 			r->in.type = m;
571 		else {
572 			/* two steps are required */
573 			NODE *x;
574 
575 			if (forarg) {
576 				x = resc;
577 				x->in.type = l->in.type;
578 				}
579 			else {
580 				x = &resc[1];
581 				*x = *l;
582 				}
583 
584 			if (tlen(x) > tlen(r) && ISUNSIGNED(r->in.type))
585 				putstr("movz");
586 			else
587 				putstr("cvt");
588 			prtype(r);
589 			prtype(x);
590 			putchar('\t');
591 			adrput(r);
592 			putchar(',');
593 			adrput(x);
594 			putchar('\n');
595 			putchar('\t');
596 			r = x;
597 			}
598 		l->in.type = (ISUNSIGNED(l->in.type) ? UNSIGNED : INT);
599 		}
600 
601 	else if ((forarg || l == resc) &&
602 		 tlen(l) < SZINT/SZCHAR &&
603 		 mixtypes(l, r)) {
604 		/* two steps needed here too */
605 		NODE *x;
606 
607 		if (forarg) {
608 			x = resc;
609 			x->in.type = l->in.type;
610 			}
611 		else {
612 			x = &resc[1];
613 			*x = *l;
614 			}
615 		putstr("cvt");
616 		prtype(r);
617 		prtype(x);
618 		putchar('\t');
619 		adrput(r);
620 		putchar(',');
621 		adrput(x);
622 		putstr("\n\t");
623 		r = x;
624 		l->in.type = (ISUNSIGNED(l->in.type) ? UNSIGNED : INT);
625 		}
626 
627 	else if ((r->in.type == UNSIGNED || r->in.type == ULONG) &&
628 	    mixtypes(l, r)) {
629 		int label1, label2;
630 		NODE *x = NULL;
631 
632 #if defined(FORT) || defined(SPRECC)
633 		if (forarg)
634 #else
635 		if (forarg || l == resc)
636 #endif
637 			{
638 			/* compute in register, convert to double when done */
639 			x = l;
640 			l = resc;
641 			l->in.type = x->in.type;
642 			}
643 
644 		label1 = getlab();
645 		label2 = getlab();
646 
647 		putstr("movl\t");
648 		adrput(r);
649 		putchar(',');
650 		adrput(l);
651 		putstr("\n\tjbsc\t$31,");
652 		adrput(l);
653 		printf(",L%d\n\tcvtl", label1);
654 		prtype(l);
655 		putchar('\t');
656 		adrput(l);
657 		putchar(',');
658 		adrput(l);
659 		printf("\n\tjbr\tL%d\nL%d:\n\tcvtl", label2, label1);
660 		prtype(l);
661 		putchar('\t');
662 		adrput(l);
663 		putchar(',');
664 		adrput(l);
665 		putstr("\n\tadd");
666 		prtype(l);
667 		putstr("2\t$0");
668 		prtype(l);
669 		putstr("2.147483648e9,");
670 		adrput(l);
671 		printf("\nL%d:", label2);
672 
673 #if defined(FORT) || defined(SPRECC)
674 		if (!forarg)
675 #else
676 		if (!forarg && (l->in.type == DOUBLE || l != resc))
677 #endif
678 			goto cleanup;
679 		if (x == NULL)
680 			cerror("sconv botch");
681 		if (l == x) {
682 			r = &resc[1];
683 			*r = *l;
684 			}
685 		else {
686 			r = l;
687 			l = x;
688 			}
689 		l->in.type = DOUBLE;
690 		putstr("\n\t");
691 		}
692 
693 	else if( (l->in.type == FLOAT || l->in.type == DOUBLE) &&
694 	    (r->in.type == UCHAR || r->in.type == USHORT) ) {
695 		/* skip unnecessary unsigned to floating conversion */
696 #if defined(FORT) || defined(SPRECC)
697 		if (forarg)
698 #else
699 		if (forarg || l == resc)
700 #endif
701 			l->in.type = DOUBLE;
702 		putstr("movz");
703 		prtype(r);
704 		putstr("l\t");
705 		adrput(r);
706 		putchar(',');
707 		adrput(resc);
708 		putstr("\n\t");
709 		if (l == resc) {
710 			r = &resc[1];
711 			*r = *l;
712 			}
713 		else
714 			r = resc;
715 		r->in.type = INT;
716 		}
717 
718 #if defined(FORT) || defined(SPRECC)
719 	if (forarg && l->in.type == FLOAT)
720 #else
721 	if ((forarg || l == resc) && l->in.type == FLOAT)
722 #endif
723 		{
724 		/* perform an implicit conversion to double */
725 		l->in.type = DOUBLE;
726 		if (r->in.type != FLOAT &&
727 		    r->in.type != CHAR &&
728 		    r->in.type != SHORT) {
729 			/* trim bits from the mantissa */
730 			putstr("cvt");
731 			prtype(r);
732 			putstr("f\t");
733 			adrput(r);
734 			putchar(',');
735 			adrput(resc);
736 			putstr("\n\t");
737 			if (l == resc) {
738 				r = &resc[1];
739 				*r = *l;
740 				}
741 			else
742 				r = resc;
743 			r->in.type = FLOAT;
744 			}
745 		}
746 
747 	if (!mixtypes(l,r)) {
748 		if (tlen(l) == tlen(r)) {
749 			if (forarg && tlen(l) == SZINT/SZCHAR) {
750 				putstr("pushl\t");
751 				adrput(r);
752 				goto cleanup;
753 				}
754 			putstr("mov");
755 #ifdef FORT
756 			if (Oflag)
757 				prtype(l);
758 			else {
759 				if (l->in.type == DOUBLE)
760 					putchar('q');
761 				else if(l->in.type == FLOAT)
762 					putchar('l');
763 				else
764 					prtype(l);
765 				}
766 #else
767 			prtype(l);
768 #endif FORT
769 			goto ops;
770 			}
771 		else if (tlen(l) > tlen(r) && ISUNSIGNED(r->in.type))
772 			putstr("movz");
773 		else
774 			putstr("cvt");
775 		}
776 	else
777 		putstr("cvt");
778 	prtype(r);
779 	prtype(l);
780 ops:
781 	putchar('\t');
782 	adrput(r);
783 	putchar(',');
784 	adrput(l);
785 
786 cleanup:
787 	if (forarg)
788 		tfree(l);
789 	}
790 
791 /*
792  * collapsible(dest, src) -- if a conversion with a register destination
793  *	can be accomplished in one instruction, return the type of src
794  *	that will do the job correctly; otherwise return 0.  Note that
795  *	a register must always end up having type INT or UNSIGNED.
796  */
797 int
798 collapsible(dest, src)
799 NODE *dest, *src;
800 {
801 	int st = src->in.type;
802 	int dt = dest->in.type;
803 	int newt = 0;
804 
805 	/*
806 	 * Are there side effects of evaluating src?
807 	 * If the derived type will not be the same size as src,
808 	 * we may have to use two steps.
809 	 */
810 	if (tlen(src) > tlen(dest)) {
811 		if (tshape(src, STARREG))
812 			return (0);
813 		if (src->in.op == OREG && R2TEST(src->tn.rval))
814 			return (0);
815 		}
816 
817 	/*
818 	 * Can we get an object of dest's type by punning src?
819 	 * Praises be to great Cthulhu for little-endian machines...
820 	 */
821 	if (st == CHAR && dt == USHORT)
822 		/*
823 		 * Special case -- we must sign-extend to 16 bits.
824 		 */
825 		return (0);
826 
827 	if (tlen(src) < tlen(dest))
828 		newt = st;
829 	else
830 		newt = dt;
831 
832 	return (newt);
833 	}
834 
835 rmove( rt, rs, t ) TWORD t; {
836 	printf( "	%s	%s,%s\n",
837 #ifdef FORT
838 		!Oflag ? (t==DOUBLE ? "movq" : "movl") :
839 #endif
840 		(t==FLOAT ? "movf" : (t==DOUBLE ? "movd" : "movl")),
841 		rnames[rs], rnames[rt] );
842 	}
843 
844 struct respref
845 respref[] = {
846 	INTAREG|INTBREG,	INTAREG|INTBREG,
847 	INAREG|INBREG,	INAREG|INBREG|SOREG|STARREG|STARNM|SNAME|SCON,
848 	INTEMP,	INTEMP,
849 	FORARG,	FORARG,
850 	INTEMP,	INTAREG|INAREG|INTBREG|INBREG|SOREG|STARREG|STARNM,
851 	0,	0 };
852 
853 setregs(){ /* set up temporary registers */
854 	fregs = 6;	/* tbl- 6 free regs on VAX (0-5) */
855 	}
856 
857 /*ARGSUSED*/
858 rewfld( p ) NODE *p; {
859 	return(1);
860 	}
861 
862 /*ARGSUSED*/
863 callreg(p) NODE *p; {
864 	return( R0 );
865 	}
866 
867 base( p ) register NODE *p; {
868 	register int o = p->in.op;
869 
870 	if( o==ICON && p->tn.name[0] != '\0' ) return( 100 ); /* ie no base reg */
871 	if( o==REG ) return( p->tn.rval );
872     if( (o==PLUS || o==MINUS) && p->in.left->in.op == REG && p->in.right->in.op==ICON)
873 		return( p->in.left->tn.rval );
874     if( o==OREG && !R2TEST(p->tn.rval) && (p->in.type==INT || p->in.type==UNSIGNED || ISPTR(p->in.type)) )
875 		return( p->tn.rval + 0200*1 );
876 	if( o==INCR && p->in.left->in.op==REG ) return( p->in.left->tn.rval + 0200*2 );
877 	if( o==ASG MINUS && p->in.left->in.op==REG) return( p->in.left->tn.rval + 0200*4 );
878 	if( o==UNARY MUL && p->in.left->in.op==INCR && p->in.left->in.left->in.op==REG
879 	  && (p->in.type==INT || p->in.type==UNSIGNED || ISPTR(p->in.type)) )
880 		return( p->in.left->in.left->tn.rval + 0200*(1+2) );
881 	if( o==NAME ) return( 100 + 0200*1 );
882 	return( -1 );
883 	}
884 
885 offset( p, tyl ) register NODE *p; int tyl; {
886 
887 	if( tyl==1 &&
888 	    p->in.op==REG &&
889 	    (p->in.type==INT || p->in.type==UNSIGNED) )
890 		return( p->tn.rval );
891 	if( p->in.op==LS &&
892 	    p->in.left->in.op==REG &&
893 	    (p->in.left->in.type==INT || p->in.left->in.type==UNSIGNED) &&
894 	    p->in.right->in.op==ICON &&
895 	    p->in.right->in.name[0]=='\0' &&
896 	    (1<<p->in.right->tn.lval)==tyl)
897 		return( p->in.left->tn.rval );
898 	if( tyl==2 &&
899 	    p->in.op==PLUS &&
900 	    (p->in.left->in.type==INT || p->in.left->in.type==UNSIGNED) &&
901 	    p->in.left->in.op==REG &&
902 	    p->in.right->in.op==REG &&
903 	    p->in.left->tn.rval==p->in.right->tn.rval )
904 		return( p->in.left->tn.rval );
905 	return( -1 );
906 	}
907 
908 makeor2( p, q, b, o) register NODE *p, *q; register int b, o; {
909 	register NODE *t;
910 	NODE *f;
911 
912 	p->in.op = OREG;
913 	f = p->in.left; 	/* have to free this subtree later */
914 
915 	/* init base */
916 	switch (q->in.op) {
917 		case ICON:
918 		case REG:
919 		case OREG:
920 		case NAME:
921 			t = q;
922 			break;
923 
924 		case MINUS:
925 			q->in.right->tn.lval = -q->in.right->tn.lval;
926 		case PLUS:
927 			t = q->in.right;
928 			break;
929 
930 		case INCR:
931 		case ASG MINUS:
932 			t = q->in.left;
933 			break;
934 
935 		case UNARY MUL:
936 			t = q->in.left->in.left;
937 			break;
938 
939 		default:
940 			cerror("illegal makeor2");
941 	}
942 
943 	p->tn.lval = t->tn.lval;
944 #ifndef FLEXNAMES
945 	{
946 		register int i;
947 		for(i=0; i<NCHNAM; ++i)
948 			p->in.name[i] = t->in.name[i];
949 	}
950 #else
951 	p->in.name = t->in.name;
952 #endif
953 
954 	/* init offset */
955 	p->tn.rval = R2PACK( (b & 0177), o, (b>>7) );
956 
957 	tfree(f);
958 	return;
959 	}
960 
961 canaddr( p ) NODE *p; {
962 	register int o = p->in.op;
963 
964 	if( o==NAME || o==REG || o==ICON || o==OREG || (o==UNARY MUL && shumul(p->in.left)) ) return(1);
965 	return(0);
966 	}
967 
968 flshape( p ) NODE *p; {
969 	register int o = p->in.op;
970 
971 	return( o == REG || o == NAME || o == ICON ||
972 		(o == OREG && (!R2TEST(p->tn.rval) || tlen(p) == 1)) );
973 	}
974 
975 /* INTEMP shapes must not contain any temporary registers */
976 shtemp( p ) register NODE *p; {
977 	int r;
978 
979 	if( p->in.op == STARG ) p = p->in.left;
980 
981 	switch (p->in.op) {
982 	case REG:
983 		return( !istreg(p->tn.rval) );
984 	case OREG:
985 		r = p->tn.rval;
986 		if( R2TEST(r) ) {
987 			if( istreg(R2UPK1(r)) )
988 				return(0);
989 			r = R2UPK2(r);
990 			}
991 		return( !istreg(r) );
992 	case UNARY MUL:
993 		p = p->in.left;
994 		return( p->in.op != UNARY MUL && shtemp(p) );
995 		}
996 
997 	if( optype( p->in.op ) != LTYPE ) return(0);
998 	return(1);
999 	}
1000 
1001 shumul( p ) register NODE *p; {
1002 	register int o;
1003 	extern int xdebug;
1004 
1005 	if (xdebug) {
1006 		int val;
1007 		printf("shumul:\n");
1008 		eprint(p, 0, &val, &val);
1009 		}
1010 
1011 	o = p->in.op;
1012 	if( o == NAME || (o == OREG && !R2TEST(p->tn.rval)) || o == ICON ) return( STARNM );
1013 
1014 	if( ( o == INCR || o == ASG MINUS ) &&
1015 	    ( p->in.left->in.op == REG && p->in.right->in.op == ICON ) &&
1016 	    p->in.right->in.name[0] == '\0' )
1017 		{
1018 		switch (p->in.type)
1019 			{
1020 			case CHAR|PTR:
1021 			case UCHAR|PTR:
1022 				o = 1;
1023 				break;
1024 
1025 			case SHORT|PTR:
1026 			case USHORT|PTR:
1027 				o = 2;
1028 				break;
1029 
1030 			case INT|PTR:
1031 			case UNSIGNED|PTR:
1032 			case LONG|PTR:
1033 			case ULONG|PTR:
1034 			case FLOAT|PTR:
1035 				o = 4;
1036 				break;
1037 
1038 			case DOUBLE|PTR:
1039 				o = 8;
1040 				break;
1041 
1042 			default:
1043 				if ( ISPTR(p->in.type) &&
1044 				     ISPTR(DECREF(p->in.type)) ) {
1045 					o = 4;
1046 					break;
1047 					}
1048 				else return(0);
1049 			}
1050 		return( p->in.right->tn.lval == o ? STARREG : 0);
1051 		}
1052 
1053 	return( 0 );
1054 	}
1055 
1056 adrcon( val ) CONSZ val; {
1057 	putchar( '$' );
1058 	printf( CONFMT, val );
1059 	}
1060 
1061 conput( p ) register NODE *p; {
1062 	switch( p->in.op ){
1063 
1064 	case ICON:
1065 		acon( p );
1066 		return;
1067 
1068 	case REG:
1069 		putstr( rnames[p->tn.rval] );
1070 		return;
1071 
1072 	default:
1073 		cerror( "illegal conput" );
1074 		}
1075 	}
1076 
1077 /*ARGSUSED*/
1078 insput( p ) NODE *p; {
1079 	cerror( "insput" );
1080 	}
1081 
1082 upput( p, size ) NODE *p; int size; {
1083 	if( size == SZLONG && p->in.op == REG ) {
1084 		putstr( rnames[p->tn.rval + 1] );
1085 		return;
1086 		}
1087 	cerror( "upput" );
1088 	}
1089 
1090 adrput( p ) register NODE *p; {
1091 	register int r;
1092 	/* output an address, with offsets, from p */
1093 
1094 	if( p->in.op == FLD ){
1095 		p = p->in.left;
1096 		}
1097 	switch( p->in.op ){
1098 
1099 	case NAME:
1100 		acon( p );
1101 		return;
1102 
1103 	case ICON:
1104 		/* addressable value of the constant */
1105 		putchar( '$' );
1106 		acon( p );
1107 		return;
1108 
1109 	case REG:
1110 		putstr( rnames[p->tn.rval] );
1111 		return;
1112 
1113 	case OREG:
1114 		r = p->tn.rval;
1115 		if( R2TEST(r) ){ /* double indexing */
1116 			register int flags;
1117 
1118 			flags = R2UPK3(r);
1119 			if( flags & 1 ) putchar('*');
1120 			if( flags & 4 ) putchar('-');
1121 			if( p->tn.lval != 0 || p->in.name[0] != '\0' ) acon(p);
1122 			if( R2UPK1(r) != 100) printf( "(%s)", rnames[R2UPK1(r)] );
1123 			if( flags & 2 ) putchar('+');
1124 			printf( "[%s]", rnames[R2UPK2(r)] );
1125 			return;
1126 			}
1127 		if( r == AP ){  /* in the argument region */
1128 			if( p->in.name[0] != '\0' ) werror( "bad arg temp" );
1129 			printf( CONFMT, p->tn.lval );
1130 			putstr( "(ap)" );
1131 			return;
1132 			}
1133 		if( p->tn.lval != 0 || p->in.name[0] != '\0') acon( p );
1134 		printf( "(%s)", rnames[p->tn.rval] );
1135 		return;
1136 
1137 	case UNARY MUL:
1138 		/* STARNM or STARREG found */
1139 		if( tshape(p, STARNM) ) {
1140 			putchar( '*' );
1141 			adrput( p->in.left);
1142 			}
1143 		else {	/* STARREG - really auto inc or dec */
1144 			register NODE *q;
1145 
1146 			q = p->in.left;
1147 			if( q->in.right->tn.lval != tlen(p) )
1148 				cerror("adrput: bad auto-increment/decrement");
1149 			printf("%s(%s)%s", (q->in.op==INCR ? "" : "-"),
1150 				rnames[q->in.left->tn.rval],
1151 				(q->in.op==INCR ? "+" : "") );
1152 			p->in.op = OREG;
1153 			p->tn.rval = q->in.left->tn.rval;
1154 			p->tn.lval = (q->in.op == INCR ? -q->in.right->tn.lval : 0);
1155 #ifndef FLEXNAMES
1156 			p->in.name[0] = '\0';
1157 #else
1158 			p->in.name = "";
1159 #endif
1160 			tfree(q);
1161 		}
1162 		return;
1163 
1164 	default:
1165 		cerror( "illegal address" );
1166 		return;
1167 
1168 		}
1169 
1170 	}
1171 
1172 acon( p ) register NODE *p; { /* print out a constant */
1173 
1174 	if( p->in.name[0] == '\0' )
1175 		printf( CONFMT, p->tn.lval);
1176 	else {
1177 #ifndef FLEXNAMES
1178 		printf( "%.8s", p->in.name );
1179 #else
1180 		putstr( p->in.name );
1181 #endif
1182 		if( p->tn.lval != 0 ) {
1183 			putchar( '+' );
1184 			printf( CONFMT, p->tn.lval );
1185 			}
1186 		}
1187 	}
1188 
1189 genscall( p, cookie ) register NODE *p; {
1190 	/* structure valued call */
1191 	return( gencall( p, cookie ) );
1192 	}
1193 
1194 /* tbl */
1195 int gc_numbytes;
1196 /* tbl */
1197 
1198 /*ARGSUSED*/
1199 gencall( p, cookie ) register NODE *p; {
1200 	/* generate the call given by p */
1201 	register NODE *p1;
1202 	register int temp, temp1;
1203 	register int m;
1204 
1205 	if( p->in.right ) temp = argsize( p->in.right );
1206 	else temp = 0;
1207 
1208 	if( p->in.op == STCALL || p->in.op == UNARY STCALL ){
1209 		/* set aside room for structure return */
1210 
1211 		if( p->stn.stsize > temp ) temp1 = p->stn.stsize;
1212 		else temp1 = temp;
1213 		}
1214 
1215 	if( temp > maxargs ) maxargs = temp;
1216 	SETOFF(temp1,4);
1217 
1218 	if( p->in.right ){ /* make temp node, put offset in, and generate args */
1219 		genargs( p->in.right );
1220 		}
1221 
1222 	p1 = p->in.left;
1223 	if( p1->in.op != ICON ){
1224 		if( p1->in.op != REG ){
1225 			if( p1->in.op != OREG || R2TEST(p1->tn.rval) ){
1226 				if( p1->in.op != NAME ){
1227 					order( p1, INAREG );
1228 					}
1229 				}
1230 			}
1231 		}
1232 
1233 /* tbl
1234 	setup gc_numbytes so reference to ZC works */
1235 
1236 	gc_numbytes = temp&(0x3ff);
1237 /* tbl */
1238 
1239 	p->in.op = UNARY CALL;
1240 	m = match( p, INTAREG|INTBREG );
1241 
1242 	/* compensate for deficiency in 'ret' instruction ... wah,kre */
1243 	/* (plus in assignment to gc_numbytes above, for neatness only) */
1244 	if (temp >= 1024)
1245 		printf("	addl2	$%d,sp\n", (temp&(~0x3ff)));
1246 
1247 	return(m != MDONE);
1248 	}
1249 
1250 /* tbl */
1251 char *
1252 ccbranches[] = {
1253 	"eql",
1254 	"neq",
1255 	"leq",
1256 	"lss",
1257 	"geq",
1258 	"gtr",
1259 	"lequ",
1260 	"lssu",
1261 	"gequ",
1262 	"gtru",
1263 	};
1264 /* tbl */
1265 
1266 /*ARGSUSED*/
1267 cbgen( o, lab, mode ) { /*   printf conditional and unconditional branches */
1268 
1269 	if( o != 0 && ( o < EQ || o > UGT ) )
1270 		cerror( "bad conditional branch: %s", opst[o] );
1271 	printf( "	j%s	L%d\n", o == 0 ? "br" : ccbranches[o-EQ], lab );
1272 	}
1273 
1274 nextcook( p, cookie ) NODE *p; {
1275 	/* we have failed to match p with cookie; try another */
1276 	if( cookie == FORREW ) return( 0 );  /* hopeless! */
1277 	if( !(cookie&(INTAREG|INTBREG)) ) return( INTAREG|INTBREG );
1278 	if( !(cookie&INTEMP) && asgop(p->in.op) ) return( INTEMP|INAREG|INTAREG|INTBREG|INBREG );
1279 	return( FORREW );
1280 	}
1281 
1282 /*ARGSUSED*/
1283 lastchance( p, cook ) NODE *p; {
1284 	/* forget it! */
1285 	return(0);
1286 	}
1287 
1288 optim2( p ) register NODE *p; {
1289 	/* do local tree transformations and optimizations */
1290 
1291 	int o;
1292 	int i, mask;
1293 	register NODE *l, *r;
1294 
1295 	switch( o = p->in.op ) {
1296 
1297 	case AND:
1298 		/* commute L and R to eliminate complements and constants */
1299 		if( (l = p->in.left)->in.op == ICON && l->in.name[0] == 0 ||
1300 		    l->in.op == COMPL ) {
1301 			p->in.left = p->in.right;
1302 			p->in.right = l;
1303 			}
1304 	case ASG AND:
1305 		/* change meaning of AND to ~R&L - bic on pdp11 */
1306 		r = p->in.right;
1307 		if( r->in.op==ICON && r->in.name[0]==0 ) {
1308 			/* check for degenerate operations */
1309 			l = p->in.left;
1310 			mask = (1 << tlen(l) * SZCHAR) - 1;
1311 			if( ISUNSIGNED(r->in.type) ) {
1312 				i = (~r->tn.lval & mask);
1313 				if( i == 0 ) {
1314 					r->in.op = FREE;
1315 					ncopy(p, l);
1316 					l->in.op = FREE;
1317 					break;
1318 					}
1319 				else if( i == mask )
1320 					goto zero;
1321 				else
1322 					r->tn.lval = i;
1323 				break;
1324 				}
1325 			else if( r->tn.lval == mask &&
1326 				 tlen(l) < SZINT/SZCHAR ) {
1327 				r->in.op = SCONV;
1328 				r->in.left = l;
1329 				r->in.right = 0;
1330 				r->in.type = ENUNSIGN(l->in.type);
1331 				r->in.su = l->in.su > 1 ? l->in.su : 1;
1332 				ncopy(p, r);
1333 				p->in.left = r;
1334 				p->in.type = INT;
1335 				break;
1336 				}
1337 			/* complement constant */
1338 			r->tn.lval = ~r->tn.lval;
1339 			}
1340 		else if( r->in.op==COMPL ) { /* ~~A => A */
1341 			r->in.op = FREE;
1342 			p->in.right = r->in.left;
1343 			}
1344 		else { /* insert complement node */
1345 			p->in.right = l = talloc();
1346 			l->in.op = COMPL;
1347 			l->in.rall = NOPREF;
1348 			l->in.type = r->in.type;
1349 			l->in.left = r;
1350 			l->in.right = NULL;
1351 			}
1352 		break;
1353 
1354 	case SCONV:
1355 		l = p->in.left;
1356 #if defined(FORT) || defined(SPRECC)
1357 		if( p->in.type == FLOAT || p->in.type == DOUBLE ||
1358 		    l->in.type == FLOAT || l->in.type == DOUBLE )
1359 			return;
1360 #else
1361 		if( mixtypes(p, l) ) return;
1362 #endif
1363 		if( l->in.op == PCONV )
1364 			return;
1365 		if( (l->in.op == CALL || l->in.op == UNARY CALL) &&
1366 		    l->in.type != INT && l->in.type != UNSIGNED )
1367 			return;
1368 
1369 		/* Only trust it to get it right if the size is the same */
1370 		if( tlen(p) != tlen(l) )
1371 			return;
1372 
1373 		/* clobber conversion */
1374 		if( l->in.op != FLD )
1375 			l->in.type = p->in.type;
1376 		ncopy( p, l );
1377 		l->in.op = FREE;
1378 
1379 		break;
1380 
1381 	case ASSIGN:
1382 		/*
1383 		 * Conversions are equivalent to assignments;
1384 		 * when the two operations are combined,
1385 		 * we can sometimes zap the conversion.
1386 		 */
1387 		r = p->in.right;
1388 		l = p->in.left;
1389 		if ( r->in.op == SCONV &&
1390 		     !mixtypes(l, r) &&
1391 		     l->in.op != FLD &&
1392 		     tlen(l) == tlen(r) ) {
1393 				p->in.right = r->in.left;
1394 				r->in.op = FREE;
1395 			}
1396 		break;
1397 
1398 	case ULE:
1399 	case ULT:
1400 	case UGE:
1401 	case UGT:
1402 		p->in.op -= (UGE-GE);
1403 		if( degenerate(p) )
1404 			break;
1405 		p->in.op += (UGE-GE);
1406 		break;
1407 
1408 	case EQ:
1409 	case NE:
1410 	case LE:
1411 	case LT:
1412 	case GE:
1413 	case GT:
1414 		if( p->in.left->in.op == SCONV &&
1415 		    p->in.right->in.op == SCONV ) {
1416 			l = p->in.left;
1417 			r = p->in.right;
1418 			if( l->in.type == DOUBLE &&
1419 			    l->in.left->in.type == FLOAT &&
1420 			    r->in.left->in.type == FLOAT ) {
1421 				/* nuke the conversions */
1422 				p->in.left = l->in.left;
1423 				p->in.right = r->in.left;
1424 				l->in.op = FREE;
1425 				r->in.op = FREE;
1426 				}
1427 			/* more? */
1428 			}
1429 		(void) degenerate(p);
1430 		break;
1431 
1432 	case DIV:
1433 		if( p->in.right->in.op == ICON &&
1434 		    p->in.right->tn.name[0] == '\0' &&
1435 		    ISUNSIGNED(p->in.right->in.type) &&
1436 		    (unsigned) p->in.right->tn.lval >= 0x80000000 ) {
1437 			/* easy to do here, harder to do in zzzcode() */
1438 			p->in.op = UGE;
1439 			break;
1440 			}
1441 	case MOD:
1442 	case ASG DIV:
1443 	case ASG MOD:
1444 		/*
1445 		 * optimize DIV and MOD
1446 		 *
1447 		 * basically we spot UCHAR and USHORT and try to do them
1448 		 * as signed ints...  apparently div+mul+sub is always
1449 		 * faster than ediv for finding MOD on the VAX, when
1450 		 * full unsigned MOD isn't needed.
1451 		 *
1452 		 * a curious fact: for MOD, cmp+sub and cmp+sub+cmp+sub
1453 		 * are faster for unsigned dividend and a constant divisor
1454 		 * in the right range (.5 to 1 of dividend's range for the
1455 		 * first, .333+ to .5 for the second).  full unsigned is
1456 		 * already done cmp+sub in the appropriate case; the
1457 		 * other cases are less common and require more ambition.
1458 		 */
1459 		if( degenerate(p) )
1460 			break;
1461 		l = p->in.left;
1462 		r = p->in.right;
1463 		if( !ISUNSIGNED(r->in.type) ||
1464 		    tlen(l) >= SZINT/SZCHAR ||
1465 		    !(tlen(r) < SZINT/SZCHAR ||
1466 		      (r->in.op == ICON && r->tn.name[0] == '\0')) )
1467 			break;
1468 		if( r->in.op == ICON )
1469 			r->tn.type = INT;
1470 		else {
1471 			NODE *t = talloc();
1472 			t->in.left = r;
1473 			r = t;
1474 			r->in.op = SCONV;
1475 			r->in.type = INT;
1476 			r->in.right = 0;
1477 			p->in.right = r;
1478 			}
1479 		if( o == DIV || o == MOD ) {
1480 			NODE *t = talloc();
1481 			t->in.left = l;
1482 			l = t;
1483 			l->in.op = SCONV;
1484 			l->in.type = INT;
1485 			l->in.right = 0;
1486 			p->in.left = l;
1487 			}
1488 		/* handle asgops in table */
1489 		break;
1490 
1491 	case RS:
1492 	case ASG RS:
1493 	case LS:
1494 	case ASG LS:
1495 		/* pick up degenerate shifts */
1496 		l = p->in.left;
1497 		r = p->in.right;
1498 		if( !(r->in.op == ICON && r->tn.name[0] == '\0') )
1499 			break;
1500 		i = r->tn.lval;
1501 		if( i < 0 )
1502 			/* front end 'fixes' this? */
1503 			if( o == LS || o == ASG LS )
1504 				o += (RS-LS);
1505 			else
1506 				o += (LS-RS);
1507 		if( (o == RS || o == ASG RS) &&
1508 		    !ISUNSIGNED(l->in.type) )
1509 			/* can't optimize signed right shifts */
1510 			break;
1511 		if( o == LS ) {
1512 			if( i < SZINT )
1513 				break;
1514 			}
1515 		else {
1516 			if( i < tlen(l) * SZCHAR )
1517 				break;
1518 			}
1519 	zero:
1520 		if( !asgop( o ) )
1521 			if( tshape(l, SAREG|SNAME|SCON|SOREG|STARNM) ) {
1522 				/* no side effects */
1523 				tfree(l);
1524 				ncopy(p, r);
1525 				r->in.op = FREE;
1526 				p->tn.lval = 0;
1527 				}
1528 			else {
1529 				p->in.op = COMOP;
1530 				r->tn.lval = 0;
1531 				}
1532 		else {
1533 			p->in.op = ASSIGN;
1534 			r->tn.lval = 0;
1535 			}
1536 		break;
1537 		}
1538 	}
1539 
1540 degenerate(p) register NODE *p; {
1541 	int o;
1542 	int result, i;
1543 	int lower, upper;
1544 	register NODE *l, *r;
1545 
1546 	/*
1547 	 * try to keep degenerate comparisons with constants
1548 	 * out of the table.
1549 	 */
1550 	r = p->in.right;
1551 	l = p->in.left;
1552 	if( r->in.op != ICON ||
1553 	    r->tn.name[0] != '\0' ||
1554 	    tlen(l) >= tlen(r) )
1555 		return (0);
1556 	switch( l->in.type ) {
1557 	case CHAR:
1558 		lower = -(1 << SZCHAR - 1);
1559 		upper = (1 << SZCHAR - 1) - 1;
1560 		break;
1561 	case UCHAR:
1562 		lower = 0;
1563 		upper = (1 << SZCHAR) - 1;
1564 		break;
1565 	case SHORT:
1566 		lower = -(1 << SZSHORT - 1);
1567 		upper = (1 << SZSHORT - 1) - 1;
1568 		break;
1569 	case USHORT:
1570 		lower = 0;
1571 		upper = (1 << SZSHORT) - 1;
1572 		break;
1573 	default:
1574 		cerror("unsupported type in degenerate()");
1575 		}
1576 	i = r->tn.lval;
1577 	switch( o = p->in.op ) {
1578 	case DIV:
1579 	case ASG DIV:
1580 	case MOD:
1581 	case ASG MOD:
1582 		/* DIV and MOD work like EQ */
1583 	case EQ:
1584 	case NE:
1585 		if( lower == 0 && (unsigned) i > upper )
1586 			result = o == NE;
1587 		else if( i < lower || i > upper )
1588 			result = o == NE;
1589 		else
1590 			return (0);
1591 		break;
1592 	case LT:
1593 	case GE:
1594 		if( lower == 0 && (unsigned) i > upper )
1595 			result = o == LT;
1596 		else if( i <= lower )
1597 			result = o != LT;
1598 		else if( i > upper )
1599 			result = o == LT;
1600 		else
1601 			return (0);
1602 		break;
1603 	case LE:
1604 	case GT:
1605 		if( lower == 0 && (unsigned) i >= upper )
1606 			result = o == LE;
1607 		else if( i < lower )
1608 			result = o != LE;
1609 		else if( i >= upper )
1610 			result = o == LE;
1611 		else
1612 			return (0);
1613 		break;
1614 	default:
1615 		cerror("unknown op in degenerate()");
1616 		}
1617 
1618 	if( o == MOD || o == ASG MOD ) {
1619 		r->in.op = FREE;
1620 		ncopy(p, l);
1621 		l->in.op = FREE;
1622 		}
1623 	else if( o != ASG DIV && tshape(l, SAREG|SNAME|SCON|SOREG|STARNM) ) {
1624 		/* no side effects */
1625 		tfree(l);
1626 		ncopy(p, r);
1627 		r->in.op = FREE;
1628 		p->tn.lval = result;
1629 		}
1630 	else {
1631 		if( o == ASG DIV )
1632 			p->in.op = ASSIGN;
1633 		else {
1634 			p->in.op = COMOP;
1635 			r->tn.type = INT;
1636 			}
1637 		r->tn.lval = result;
1638 		}
1639 	if( logop(o) )
1640 		p->in.type = INT;
1641 
1642 	return (1);
1643 	}
1644 
1645 /* added by jwf */
1646 struct functbl {
1647 	int fop;
1648 	TWORD ftype;
1649 	char *func;
1650 	} opfunc[] = {
1651 	DIV,		TANY,	"udiv",
1652 	MOD,		TANY,	"urem",
1653 	ASG DIV,	TANY,	"audiv",
1654 	ASG MOD,	TANY,	"aurem",
1655 	0,	0,	0 };
1656 
1657 hardops(p)  register NODE *p; {
1658 	/* change hard to do operators into function calls.  */
1659 	register NODE *q;
1660 	register struct functbl *f;
1661 	register o;
1662 	NODE *old,*temp;
1663 
1664 	o = p->in.op;
1665 	if( ! (optype(o)==BITYPE &&
1666 	       (ISUNSIGNED(p->in.left->in.type) ||
1667 		ISUNSIGNED(p->in.right->in.type))) )
1668 		return;
1669 
1670 	for( f=opfunc; f->fop; f++ ) {
1671 		if( o==f->fop ) goto convert;
1672 		}
1673 	return;
1674 
1675 	convert:
1676 	if( p->in.right->in.op == ICON && p->in.right->tn.name[0] == '\0' )
1677 		/* 'J', 'K' in zzzcode() -- assumes DIV or MOD operations */
1678 		/* save a subroutine call -- use at most 5 instructions */
1679 		return;
1680 	if( tlen(p->in.left) < SZINT/SZCHAR && tlen(p->in.right) < SZINT/SZCHAR )
1681 		/* optim2() will modify the op into an ordinary int op */
1682 		return;
1683 	if( asgop( o ) ) {
1684 		old = NIL;
1685 		switch( p->in.left->in.op ){
1686 		case FLD:
1687 			q = p->in.left->in.left;
1688 			/*
1689 			 * rewrite (lval.fld /= rval); as
1690 			 *  ((*temp).fld = udiv((*(temp = &lval)).fld,rval));
1691 			 * else the compiler will evaluate lval twice.
1692 			 */
1693 			if( q->in.op == UNARY MUL ){
1694 				/* first allocate a temp storage */
1695 				temp = talloc();
1696 				temp->in.op = OREG;
1697 				temp->tn.rval = TMPREG;
1698 				temp->tn.lval = BITOOR(freetemp(1));
1699 				temp->in.type = INCREF(p->in.type);
1700 #ifdef FLEXNAMES
1701 				temp->in.name = "";
1702 #else
1703 				temp->in.name[0] = '\0';
1704 #endif
1705 				old = q->in.left;
1706 				q->in.left = temp;
1707 			}
1708 			/* fall thru ... */
1709 
1710 		case REG:
1711 		case NAME:
1712 		case OREG:
1713 			/* change ASG OP to a simple OP */
1714 			q = talloc();
1715 			q->in.op = NOASG p->in.op;
1716 			q->in.rall = NOPREF;
1717 			q->in.type = p->in.type;
1718 			q->in.left = tcopy(p->in.left);
1719 			q->in.right = p->in.right;
1720 			p->in.op = ASSIGN;
1721 			p->in.right = q;
1722 			p = q;
1723 			f -= 2; /* Note: this depends on the table order */
1724 			/* on the right side only - replace *temp with
1725 			 *(temp = &lval), build the assignment node */
1726 			if( old ){
1727 				temp = q->in.left->in.left; /* the "*" node */
1728 				q = talloc();
1729 				q->in.op = ASSIGN;
1730 				q->in.left = temp->in.left;
1731 				q->in.right = old;
1732 				q->in.type = old->in.type;
1733 #ifdef FLEXNAMES
1734 				q->in.name = "";
1735 #else
1736 				q->in.name[0] = '\0';
1737 #endif
1738 				temp->in.left = q;
1739 			}
1740 			break;
1741 
1742 		case UNARY MUL:
1743 			/* avoid doing side effects twice */
1744 			q = p->in.left;
1745 			p->in.left = q->in.left;
1746 			q->in.op = FREE;
1747 			break;
1748 
1749 		default:
1750 			cerror( "hardops: can't compute & LHS" );
1751 			}
1752 		}
1753 
1754 	/* build comma op for args to function */
1755 	q = talloc();
1756 	q->in.op = CM;
1757 	q->in.rall = NOPREF;
1758 	q->in.type = INT;
1759 	q->in.left = p->in.left;
1760 	q->in.right = p->in.right;
1761 	p->in.op = CALL;
1762 	p->in.right = q;
1763 
1764 	/* put function name in left node of call */
1765 	p->in.left = q = talloc();
1766 	q->in.op = ICON;
1767 	q->in.rall = NOPREF;
1768 	q->in.type = INCREF( FTN + p->in.type );
1769 #ifndef FLEXNAMES
1770 	strcpy( q->in.name, f->func );
1771 #else
1772 	q->in.name = f->func;
1773 #endif
1774 	q->tn.lval = 0;
1775 	q->tn.rval = 0;
1776 
1777 	}
1778 
1779 zappost(p) NODE *p; {
1780 	/* look for ++ and -- operators and remove them */
1781 
1782 	register int o, ty;
1783 	register NODE *q;
1784 	o = p->in.op;
1785 	ty = optype( o );
1786 
1787 	switch( o ){
1788 
1789 	case INCR:
1790 	case DECR:
1791 			q = p->in.left;
1792 			p->in.right->in.op = FREE;  /* zap constant */
1793 			ncopy( p, q );
1794 			q->in.op = FREE;
1795 			return;
1796 
1797 		}
1798 
1799 	if( ty == BITYPE ) zappost( p->in.right );
1800 	if( ty != LTYPE ) zappost( p->in.left );
1801 }
1802 
1803 fixpre(p) NODE *p; {
1804 
1805 	register int o, ty;
1806 	o = p->in.op;
1807 	ty = optype( o );
1808 
1809 	switch( o ){
1810 
1811 	case ASG PLUS:
1812 			p->in.op = PLUS;
1813 			break;
1814 	case ASG MINUS:
1815 			p->in.op = MINUS;
1816 			break;
1817 		}
1818 
1819 	if( ty == BITYPE ) fixpre( p->in.right );
1820 	if( ty != LTYPE ) fixpre( p->in.left );
1821 }
1822 
1823 /*ARGSUSED*/
1824 NODE * addroreg(l) NODE *l;
1825 				/* OREG was built in clocal()
1826 				 * for an auto or formal parameter
1827 				 * now its address is being taken
1828 				 * local code must unwind it
1829 				 * back to PLUS/MINUS REG ICON
1830 				 * according to local conventions
1831 				 */
1832 {
1833 	cerror("address of OREG taken");
1834 	/*NOTREACHED*/
1835 }
1836 
1837 
1838 
1839 # ifndef ONEPASS
1840 main( argc, argv ) char *argv[]; {
1841 	return( mainp2( argc, argv ) );
1842 	}
1843 # endif
1844 
1845 strip(p) register NODE *p; {
1846 	NODE *q;
1847 
1848 	/* strip nodes off the top when no side effects occur */
1849 	for( ; ; ) {
1850 		switch( p->in.op ) {
1851 		case SCONV:			/* remove lint tidbits */
1852 			q = p->in.left;
1853 			ncopy( p, q );
1854 			q->in.op = FREE;
1855 			break;
1856 		/* could probably add a few more here */
1857 		default:
1858 			return;
1859 			}
1860 		}
1861 	}
1862 
1863 myreader(p) register NODE *p; {
1864 	strip( p );		/* strip off operations with no side effects */
1865 	canon( p );		/* expands r-vals for fields */
1866 	walkf( p, hardops );	/* convert ops to function calls */
1867 	walkf( p, optim2 );
1868 	}
1869