xref: /csrg-svn/old/pcc/ccom.vax/local2.c (revision 32944)
1 # ifndef lint
2 static char *sccsid ="@(#)local2.c	1.38 (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 ASG PLUS:
1298 	case ASG MINUS:
1299 	case ASG MUL:
1300 	case ASG OR:
1301 		/* simple ASG OPSIMP -- reduce range of constant rhs */
1302 		l = p->in.left;
1303 		r = p->in.right;
1304 		if( tlen(l) < SZINT/SZCHAR &&
1305 		    r->in.op==ICON && r->in.name[0]==0 ){
1306 			mask = (1 << tlen(l) * SZCHAR) - 1;
1307 			if( r->tn.lval & (mask & ~(mask >> 1)) )
1308 				r->tn.lval |= ~mask;
1309 			else
1310 				r->tn.lval &= mask;
1311 			}
1312 		break;
1313 
1314 	case AND:
1315 		/* commute L and R to eliminate complements and constants */
1316 		if( (l = p->in.left)->in.op == ICON && l->in.name[0] == 0 ||
1317 		    l->in.op == COMPL ) {
1318 			p->in.left = p->in.right;
1319 			p->in.right = l;
1320 			}
1321 		/* fall through */
1322 
1323 	case ASG AND:
1324 		/* change meaning of AND to ~R&L - bic on pdp11/vax */
1325 		r = p->in.right;
1326 		if( r->in.op==ICON && r->in.name[0]==0 ) {
1327 			/* check for degenerate operations */
1328 			l = p->in.left;
1329 			mask = (1 << tlen(l) * SZCHAR) - 1;
1330 			if( o == ASG AND || ISUNSIGNED(r->in.type) ) {
1331 				i = ~r->tn.lval & mask;
1332 				if( i == 0 ) {
1333 					/* redundant mask */
1334 					r->in.op = FREE;
1335 					ncopy(p, l);
1336 					l->in.op = FREE;
1337 					break;
1338 					}
1339 				else if( i == mask )
1340 					/* all bits masked off */
1341 					goto zero;
1342 				r->tn.lval = i;
1343 				if( tlen(l) < SZINT/SZCHAR ){
1344 					/* sign extend */
1345 					if( r->tn.lval & (mask & ~(mask >> 1)) )
1346 						r->tn.lval |= ~mask;
1347 					else
1348 						r->tn.lval &= mask;
1349 					}
1350 				break;
1351 				}
1352 			else if( r->tn.lval == mask &&
1353 				 tlen(l) < SZINT/SZCHAR ) {
1354 				/* use movz instead of bic */
1355 				r->in.op = SCONV;
1356 				r->in.left = l;
1357 				r->in.right = 0;
1358 				r->in.type = ENUNSIGN(l->in.type);
1359 				r->in.su = l->in.su > 1 ? l->in.su : 1;
1360 				ncopy(p, r);
1361 				p->in.left = r;
1362 				p->in.type = INT;
1363 				break;
1364 				}
1365 			/* complement constant */
1366 			r->tn.lval = ~r->tn.lval;
1367 			}
1368 		else if( r->in.op==COMPL ) { /* ~~A => A */
1369 			r->in.op = FREE;
1370 			p->in.right = r->in.left;
1371 			}
1372 		else { /* insert complement node */
1373 			p->in.right = l = talloc();
1374 			l->in.op = COMPL;
1375 			l->in.rall = NOPREF;
1376 			l->in.type = r->in.type;
1377 			l->in.left = r;
1378 			l->in.right = NULL;
1379 			}
1380 		break;
1381 
1382 	case SCONV:
1383 		l = p->in.left;
1384 #if defined(FORT) || defined(SPRECC)
1385 		if( p->in.type == FLOAT || p->in.type == DOUBLE ||
1386 		    l->in.type == FLOAT || l->in.type == DOUBLE )
1387 			return;
1388 #else
1389 		if( mixtypes(p, l) ) return;
1390 #endif
1391 		if( l->in.op == PCONV )
1392 			return;
1393 		if( (l->in.op == CALL || l->in.op == UNARY CALL) &&
1394 		    l->in.type != INT && l->in.type != UNSIGNED )
1395 			return;
1396 
1397 		/* Only trust it to get it right if the size is the same */
1398 		if( tlen(p) != tlen(l) )
1399 			return;
1400 
1401 		/* clobber conversion */
1402 		if( l->in.op != FLD )
1403 			l->in.type = p->in.type;
1404 		ncopy( p, l );
1405 		l->in.op = FREE;
1406 
1407 		break;
1408 
1409 	case ASSIGN:
1410 		/*
1411 		 * Conversions are equivalent to assignments;
1412 		 * when the two operations are combined,
1413 		 * we can sometimes zap the conversion.
1414 		 */
1415 		r = p->in.right;
1416 		l = p->in.left;
1417 		if ( r->in.op == SCONV &&
1418 		     !mixtypes(l, r) &&
1419 		     l->in.op != FLD &&
1420 		     tlen(l) == tlen(r) ) {
1421 				p->in.right = r->in.left;
1422 				r->in.op = FREE;
1423 			}
1424 		break;
1425 
1426 	case ULE:
1427 	case ULT:
1428 	case UGE:
1429 	case UGT:
1430 		p->in.op -= (UGE-GE);
1431 		if( degenerate(p) )
1432 			break;
1433 		p->in.op += (UGE-GE);
1434 		break;
1435 
1436 	case EQ:
1437 	case NE:
1438 	case LE:
1439 	case LT:
1440 	case GE:
1441 	case GT:
1442 		if( p->in.left->in.op == SCONV &&
1443 		    p->in.right->in.op == SCONV ) {
1444 			l = p->in.left;
1445 			r = p->in.right;
1446 			if( l->in.type == DOUBLE &&
1447 			    l->in.left->in.type == FLOAT &&
1448 			    r->in.left->in.type == FLOAT ) {
1449 				/* nuke the conversions */
1450 				p->in.left = l->in.left;
1451 				p->in.right = r->in.left;
1452 				l->in.op = FREE;
1453 				r->in.op = FREE;
1454 				}
1455 			/* more? */
1456 			}
1457 		(void) degenerate(p);
1458 		break;
1459 
1460 	case DIV:
1461 		if( p->in.right->in.op == ICON &&
1462 		    p->in.right->tn.name[0] == '\0' &&
1463 		    ISUNSIGNED(p->in.right->in.type) &&
1464 		    (unsigned) p->in.right->tn.lval >= 0x80000000 ) {
1465 			/* easy to do here, harder to do in zzzcode() */
1466 			p->in.op = UGE;
1467 			break;
1468 			}
1469 	case MOD:
1470 	case ASG DIV:
1471 	case ASG MOD:
1472 		/*
1473 		 * optimize DIV and MOD
1474 		 *
1475 		 * basically we spot UCHAR and USHORT and try to do them
1476 		 * as signed ints...  apparently div+mul+sub is always
1477 		 * faster than ediv for finding MOD on the VAX, when
1478 		 * full unsigned MOD isn't needed.
1479 		 *
1480 		 * a curious fact: for MOD, cmp+sub and cmp+sub+cmp+sub
1481 		 * are faster for unsigned dividend and a constant divisor
1482 		 * in the right range (.5 to 1 of dividend's range for the
1483 		 * first, .333+ to .5 for the second).  full unsigned is
1484 		 * already done cmp+sub in the appropriate case; the
1485 		 * other cases are less common and require more ambition.
1486 		 */
1487 		if( degenerate(p) )
1488 			break;
1489 		l = p->in.left;
1490 		r = p->in.right;
1491 		if( !ISUNSIGNED(r->in.type) ||
1492 		    tlen(l) >= SZINT/SZCHAR ||
1493 		    !(tlen(r) < SZINT/SZCHAR ||
1494 		      (r->in.op == ICON && r->tn.name[0] == '\0')) )
1495 			break;
1496 		if( r->in.op == ICON )
1497 			r->tn.type = INT;
1498 		else {
1499 			NODE *t = talloc();
1500 			t->in.left = r;
1501 			r = t;
1502 			r->in.op = SCONV;
1503 			r->in.type = INT;
1504 			r->in.right = 0;
1505 			p->in.right = r;
1506 			}
1507 		if( o == DIV || o == MOD ) {
1508 			NODE *t = talloc();
1509 			t->in.left = l;
1510 			l = t;
1511 			l->in.op = SCONV;
1512 			l->in.type = INT;
1513 			l->in.right = 0;
1514 			p->in.left = l;
1515 			}
1516 		/* handle asgops in table */
1517 		break;
1518 
1519 	case RS:
1520 	case ASG RS:
1521 	case LS:
1522 	case ASG LS:
1523 		/* pick up degenerate shifts */
1524 		l = p->in.left;
1525 		r = p->in.right;
1526 		if( !(r->in.op == ICON && r->tn.name[0] == '\0') )
1527 			break;
1528 		i = r->tn.lval;
1529 		if( i < 0 )
1530 			/* front end 'fixes' this? */
1531 			if( o == LS || o == ASG LS )
1532 				o += (RS-LS);
1533 			else
1534 				o += (LS-RS);
1535 		if( (o == RS || o == ASG RS) &&
1536 		    !ISUNSIGNED(l->in.type) )
1537 			/* can't optimize signed right shifts */
1538 			break;
1539 		if( o == LS ) {
1540 			if( i < SZINT )
1541 				break;
1542 			}
1543 		else {
1544 			if( i < tlen(l) * SZCHAR )
1545 				break;
1546 			}
1547 	zero:
1548 		if( !asgop( o ) )
1549 			if( tshape(l, SAREG|SNAME|SCON|SOREG|STARNM) ) {
1550 				/* no side effects */
1551 				tfree(l);
1552 				ncopy(p, r);
1553 				r->in.op = FREE;
1554 				p->tn.lval = 0;
1555 				}
1556 			else {
1557 				p->in.op = COMOP;
1558 				r->tn.lval = 0;
1559 				}
1560 		else {
1561 			p->in.op = ASSIGN;
1562 			r->tn.lval = 0;
1563 			}
1564 		break;
1565 		}
1566 	}
1567 
1568 degenerate(p) register NODE *p; {
1569 	int o;
1570 	int result, i;
1571 	int lower, upper;
1572 	register NODE *l, *r;
1573 
1574 	/*
1575 	 * try to keep degenerate comparisons with constants
1576 	 * out of the table.
1577 	 */
1578 	r = p->in.right;
1579 	l = p->in.left;
1580 	if( r->in.op != ICON ||
1581 	    r->tn.name[0] != '\0' ||
1582 	    tlen(l) >= tlen(r) )
1583 		return (0);
1584 	switch( l->in.type ) {
1585 	case CHAR:
1586 		lower = -(1 << SZCHAR - 1);
1587 		upper = (1 << SZCHAR - 1) - 1;
1588 		break;
1589 	case UCHAR:
1590 		lower = 0;
1591 		upper = (1 << SZCHAR) - 1;
1592 		break;
1593 	case SHORT:
1594 		lower = -(1 << SZSHORT - 1);
1595 		upper = (1 << SZSHORT - 1) - 1;
1596 		break;
1597 	case USHORT:
1598 		lower = 0;
1599 		upper = (1 << SZSHORT) - 1;
1600 		break;
1601 	default:
1602 		cerror("unsupported type in degenerate()");
1603 		}
1604 	i = r->tn.lval;
1605 	switch( o = p->in.op ) {
1606 	case DIV:
1607 	case ASG DIV:
1608 	case MOD:
1609 	case ASG MOD:
1610 		/* DIV and MOD work like EQ */
1611 	case EQ:
1612 	case NE:
1613 		if( lower == 0 && (unsigned) i > upper )
1614 			result = o == NE;
1615 		else if( i < lower || i > upper )
1616 			result = o == NE;
1617 		else
1618 			return (0);
1619 		break;
1620 	case LT:
1621 	case GE:
1622 		if( lower == 0 && (unsigned) i > upper )
1623 			result = o == LT;
1624 		else if( i <= lower )
1625 			result = o != LT;
1626 		else if( i > upper )
1627 			result = o == LT;
1628 		else
1629 			return (0);
1630 		break;
1631 	case LE:
1632 	case GT:
1633 		if( lower == 0 && (unsigned) i >= upper )
1634 			result = o == LE;
1635 		else if( i < lower )
1636 			result = o != LE;
1637 		else if( i >= upper )
1638 			result = o == LE;
1639 		else
1640 			return (0);
1641 		break;
1642 	default:
1643 		cerror("unknown op in degenerate()");
1644 		}
1645 
1646 	if( o == MOD || o == ASG MOD ) {
1647 		r->in.op = FREE;
1648 		ncopy(p, l);
1649 		l->in.op = FREE;
1650 		}
1651 	else if( o != ASG DIV && tshape(l, SAREG|SNAME|SCON|SOREG|STARNM) ) {
1652 		/* no side effects */
1653 		tfree(l);
1654 		ncopy(p, r);
1655 		r->in.op = FREE;
1656 		p->tn.lval = result;
1657 		}
1658 	else {
1659 		if( o == ASG DIV )
1660 			p->in.op = ASSIGN;
1661 		else {
1662 			p->in.op = COMOP;
1663 			r->tn.type = INT;
1664 			}
1665 		r->tn.lval = result;
1666 		}
1667 	if( logop(o) )
1668 		p->in.type = INT;
1669 
1670 	return (1);
1671 	}
1672 
1673 /* added by jwf */
1674 struct functbl {
1675 	int fop;
1676 	TWORD ftype;
1677 	char *func;
1678 	} opfunc[] = {
1679 	DIV,		TANY,	"udiv",
1680 	MOD,		TANY,	"urem",
1681 	ASG DIV,	TANY,	"audiv",
1682 	ASG MOD,	TANY,	"aurem",
1683 	0,	0,	0 };
1684 
1685 hardops(p)  register NODE *p; {
1686 	/* change hard to do operators into function calls.  */
1687 	register NODE *q;
1688 	register struct functbl *f;
1689 	register o;
1690 	NODE *old,*temp;
1691 
1692 	o = p->in.op;
1693 	if( ! (optype(o)==BITYPE &&
1694 	       (ISUNSIGNED(p->in.left->in.type) ||
1695 		ISUNSIGNED(p->in.right->in.type))) )
1696 		return;
1697 
1698 	for( f=opfunc; f->fop; f++ ) {
1699 		if( o==f->fop ) goto convert;
1700 		}
1701 	return;
1702 
1703 	convert:
1704 	if( p->in.right->in.op == ICON && p->in.right->tn.name[0] == '\0' )
1705 		/* 'J', 'K' in zzzcode() -- assumes DIV or MOD operations */
1706 		/* save a subroutine call -- use at most 5 instructions */
1707 		return;
1708 	if( tlen(p->in.left) < SZINT/SZCHAR && tlen(p->in.right) < SZINT/SZCHAR )
1709 		/* optim2() will modify the op into an ordinary int op */
1710 		return;
1711 	if( asgop( o ) ) {
1712 		old = NIL;
1713 		switch( p->in.left->in.op ){
1714 		case FLD:
1715 			q = p->in.left->in.left;
1716 			/*
1717 			 * rewrite (lval.fld /= rval); as
1718 			 *  ((*temp).fld = udiv((*(temp = &lval)).fld,rval));
1719 			 * else the compiler will evaluate lval twice.
1720 			 */
1721 			if( q->in.op == UNARY MUL ){
1722 				/* first allocate a temp storage */
1723 				temp = talloc();
1724 				temp->in.op = OREG;
1725 				temp->tn.rval = TMPREG;
1726 				temp->tn.lval = BITOOR(freetemp(1));
1727 				temp->in.type = INCREF(p->in.type);
1728 #ifdef FLEXNAMES
1729 				temp->in.name = "";
1730 #else
1731 				temp->in.name[0] = '\0';
1732 #endif
1733 				old = q->in.left;
1734 				q->in.left = temp;
1735 			}
1736 			/* fall thru ... */
1737 
1738 		case REG:
1739 		case NAME:
1740 		case OREG:
1741 			/* change ASG OP to a simple OP */
1742 			q = talloc();
1743 			q->in.op = NOASG p->in.op;
1744 			q->in.rall = NOPREF;
1745 			q->in.type = p->in.type;
1746 			q->in.left = tcopy(p->in.left);
1747 			q->in.right = p->in.right;
1748 			p->in.op = ASSIGN;
1749 			p->in.right = q;
1750 			p = q;
1751 			f -= 2; /* Note: this depends on the table order */
1752 			/* on the right side only - replace *temp with
1753 			 *(temp = &lval), build the assignment node */
1754 			if( old ){
1755 				temp = q->in.left->in.left; /* the "*" node */
1756 				q = talloc();
1757 				q->in.op = ASSIGN;
1758 				q->in.left = temp->in.left;
1759 				q->in.right = old;
1760 				q->in.type = old->in.type;
1761 #ifdef FLEXNAMES
1762 				q->in.name = "";
1763 #else
1764 				q->in.name[0] = '\0';
1765 #endif
1766 				temp->in.left = q;
1767 			}
1768 			break;
1769 
1770 		case UNARY MUL:
1771 			/* avoid doing side effects twice */
1772 			q = p->in.left;
1773 			p->in.left = q->in.left;
1774 			q->in.op = FREE;
1775 			break;
1776 
1777 		default:
1778 			cerror( "hardops: can't compute & LHS" );
1779 			}
1780 		}
1781 
1782 	/* build comma op for args to function */
1783 	q = talloc();
1784 	q->in.op = CM;
1785 	q->in.rall = NOPREF;
1786 	q->in.type = INT;
1787 	q->in.left = p->in.left;
1788 	q->in.right = p->in.right;
1789 	p->in.op = CALL;
1790 	p->in.right = q;
1791 
1792 	/* put function name in left node of call */
1793 	p->in.left = q = talloc();
1794 	q->in.op = ICON;
1795 	q->in.rall = NOPREF;
1796 	q->in.type = INCREF( FTN + p->in.type );
1797 #ifndef FLEXNAMES
1798 	strcpy( q->in.name, f->func );
1799 #else
1800 	q->in.name = f->func;
1801 #endif
1802 	q->tn.lval = 0;
1803 	q->tn.rval = 0;
1804 
1805 	}
1806 
1807 zappost(p) NODE *p; {
1808 	/* look for ++ and -- operators and remove them */
1809 
1810 	register int o, ty;
1811 	register NODE *q;
1812 	o = p->in.op;
1813 	ty = optype( o );
1814 
1815 	switch( o ){
1816 
1817 	case INCR:
1818 	case DECR:
1819 			q = p->in.left;
1820 			p->in.right->in.op = FREE;  /* zap constant */
1821 			ncopy( p, q );
1822 			q->in.op = FREE;
1823 			return;
1824 
1825 		}
1826 
1827 	if( ty == BITYPE ) zappost( p->in.right );
1828 	if( ty != LTYPE ) zappost( p->in.left );
1829 }
1830 
1831 fixpre(p) NODE *p; {
1832 
1833 	register int o, ty;
1834 	o = p->in.op;
1835 	ty = optype( o );
1836 
1837 	switch( o ){
1838 
1839 	case ASG PLUS:
1840 			p->in.op = PLUS;
1841 			break;
1842 	case ASG MINUS:
1843 			p->in.op = MINUS;
1844 			break;
1845 		}
1846 
1847 	if( ty == BITYPE ) fixpre( p->in.right );
1848 	if( ty != LTYPE ) fixpre( p->in.left );
1849 }
1850 
1851 /*ARGSUSED*/
1852 NODE * addroreg(l) NODE *l;
1853 				/* OREG was built in clocal()
1854 				 * for an auto or formal parameter
1855 				 * now its address is being taken
1856 				 * local code must unwind it
1857 				 * back to PLUS/MINUS REG ICON
1858 				 * according to local conventions
1859 				 */
1860 {
1861 	cerror("address of OREG taken");
1862 	/*NOTREACHED*/
1863 }
1864 
1865 
1866 
1867 # ifndef ONEPASS
1868 main( argc, argv ) char *argv[]; {
1869 	return( mainp2( argc, argv ) );
1870 	}
1871 # endif
1872 
1873 strip(p) register NODE *p; {
1874 	NODE *q;
1875 
1876 	/* strip nodes off the top when no side effects occur */
1877 	for( ; ; ) {
1878 		switch( p->in.op ) {
1879 		case SCONV:			/* remove lint tidbits */
1880 			q = p->in.left;
1881 			ncopy( p, q );
1882 			q->in.op = FREE;
1883 			break;
1884 		/* could probably add a few more here */
1885 		default:
1886 			return;
1887 			}
1888 		}
1889 	}
1890 
1891 myreader(p) register NODE *p; {
1892 	strip( p );		/* strip off operations with no side effects */
1893 	canon( p );		/* expands r-vals for fields */
1894 	walkf( p, hardops );	/* convert ops to function calls */
1895 	walkf( p, optim2 );
1896 	}
1897