compilers were inconsistent about

whether no register argument was
REGARG == 0 or REGARG < 0.
use REGARG < 0 because arm needs 0 for R0.

R=ken
OCL=31562
CL=31566

src/cmd/6c/cgen.c

@@ -923,7 +923,9 @@ cgen(Node *n, Node *nn)
 
 			return;
 		}
-		o = reg[REGARG];
+		o = 0;
+		if(REGARG >= 0)
+			o = reg[REGARG];
 		gargs(r, &nod, &nod1);
 		if(l->addable < INDEXED) {
 			reglcgen(&nod, l, nn);
@@ -932,7 +934,7 @@ cgen(Node *n, Node *nn)
 			regfree(&nod);
 		} else
 			gopcode(OFUNC, n->type, Z, l);
-		if(REGARG)
+		if(REGARG >= 0)
 			if(o != reg[REGARG])
 				reg[REGARG]--;
 		if(nn != Z) {

src/cmd/6c/peep.c

@@ -799,7 +799,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 	case ACALL:	/* funny */
 		if(REGEXT && v->type <= REGEXT && v->type > exregoffset)
 			return 2;
-		if(REGARG && v->type == REGARG)
+		if(REGARG >= 0 && v->type == REGARG)
 			return 2;
 
 		if(s != A) {
@@ -812,7 +812,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 		return 3;
 
 	case ATEXT:	/* funny */
-		if(REGARG && v->type == REGARG)
+		if(REGARG >= 0 && v->type == REGARG)
 			return 3;
 		return 0;
 	}

src/cmd/6c/txt.c

@@ -247,7 +247,7 @@ garg1(Node *n, Node *tn1, Node *tn2, int f, Node **fnxp)
 			sugen(n, tn2, n->type->width);
 		return;
 	}
-	if(REGARG && curarg == 0 && typechlpv[n->type->etype]) {
+	if(REGARG >= 0 && curarg == 0 && typechlpv[n->type->etype]) {
 		regaalloc1(tn1, n);
 		if(n->complex >= FNX) {
 			cgen(*fnxp, tn1);
@@ -437,8 +437,8 @@ regsalloc(Node *n, Node *nn)
 void
 regaalloc1(Node *n, Node *nn)
 {
-	if(REGARG == 0)
-		diag(n, "regaalloc1 and REGARG==0");
+	if(REGARG < 0)
+		diag(n, "regaalloc1 and REGARG<0");
 	nodreg(n, nn, REGARG);
 	reg[REGARG]++;
 	curarg = align(curarg, nn->type, Aarg1);
@@ -1475,7 +1475,7 @@ gpseudo(int a, Sym *s, Node *n)
 	p->from.sym = s;
 	p->from.scale = textflag;
 	textflag = 0;
-	
+
 	if(s->class == CSTATIC)
 		p->from.type = D_STATIC;
 	naddr(n, &p->to);
@@ -1513,8 +1513,8 @@ exreg(Type *t)
 
 schar	ewidth[NTYPE] =
 {
-	-1,		/*[TXXX]*/	
-	SZ_CHAR,	/*[TCHAR]*/	
+	-1,		/*[TXXX]*/
+	SZ_CHAR,	/*[TCHAR]*/
 	SZ_CHAR,	/*[TUCHAR]*/
 	SZ_SHORT,	/*[TSHORT]*/
 	SZ_SHORT,	/*[TUSHORT]*/
@@ -1538,10 +1538,10 @@ int32	ncast[NTYPE] =
 {
 	0,				/*[TXXX]*/
 	BCHAR|BUCHAR,			/*[TCHAR]*/
-	BCHAR|BUCHAR,			/*[TUCHAR]*/	
+	BCHAR|BUCHAR,			/*[TUCHAR]*/
 	BSHORT|BUSHORT,			/*[TSHORT]*/
 	BSHORT|BUSHORT,			/*[TUSHORT]*/
-	BINT|BUINT|BLONG|BULONG,	/*[TINT]*/		
+	BINT|BUINT|BLONG|BULONG,	/*[TINT]*/
 	BINT|BUINT|BLONG|BULONG,	/*[TUINT]*/
 	BINT|BUINT|BLONG|BULONG,	/*[TLONG]*/
 	BINT|BUINT|BLONG|BULONG,	/*[TULONG]*/

src/cmd/6l/6.out.h

@@ -832,7 +832,7 @@ enum
 	T_SCONST	= 1<<5,
 	T_64		= 1<<6,
 
-	REGARG		= 0,
+	REGARG		= -1,
 	REGRET		= D_AX,
 	FREGRET		= D_X0,
 	REGSP		= D_SP,

src/cmd/8c/cgen.c

@@ -925,7 +925,7 @@ cgen(Node *n, Node *nn)
 			regfree(&nod);
 		} else
 			gopcode(OFUNC, n->type, Z, l);
-		if(REGARG && reg[REGARG])
+		if(REGARG >= 0 && reg[REGARG])
 			reg[REGARG]--;
 		if(nn != Z) {
 			regret(&nod, n);

src/cmd/8c/peep.c

@@ -713,7 +713,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 		return 3;
 
 	case ACALL:	/* funny */
-		if(REGARG && v->type == REGARG)
+		if(REGARG >= 0 && v->type == REGARG)
 			return 2;
 
 		if(s != A) {

src/cmd/8c/txt.c

@@ -233,7 +233,7 @@ garg1(Node *n, Node *tn1, Node *tn2, int f, Node **fnxp)
 			sugen(n, tn2, n->type->width);
 		return;
 	}
-	if(REGARG && curarg == 0 && typeilp[n->type->etype]) {
+	if(REGARG >= 0 && curarg == 0 && typeilp[n->type->etype]) {
 		regaalloc1(tn1, n);
 		if(n->complex >= FNX) {
 			cgen(*fnxp, tn1);
@@ -1409,8 +1409,8 @@ exreg(Type *t)
 
 schar	ewidth[NTYPE] =
 {
-	-1,		/*[TXXX]*/	
-	SZ_CHAR,	/*[TCHAR]*/	
+	-1,		/*[TXXX]*/
+	SZ_CHAR,	/*[TCHAR]*/
 	SZ_CHAR,	/*[TUCHAR]*/
 	SZ_SHORT,	/*[TSHORT]*/
 	SZ_SHORT,	/*[TUSHORT]*/
@@ -1434,10 +1434,10 @@ int32	ncast[NTYPE] =
 {
 	0,				/*[TXXX]*/
 	BCHAR|BUCHAR,			/*[TCHAR]*/
-	BCHAR|BUCHAR,			/*[TUCHAR]*/	
+	BCHAR|BUCHAR,			/*[TUCHAR]*/
 	BSHORT|BUSHORT,			/*[TSHORT]*/
 	BSHORT|BUSHORT,			/*[TUSHORT]*/
-	BINT|BUINT|BLONG|BULONG|BIND,	/*[TINT]*/		
+	BINT|BUINT|BLONG|BULONG|BIND,	/*[TINT]*/
 	BINT|BUINT|BLONG|BULONG|BIND,	/*[TUINT]*/
 	BINT|BUINT|BLONG|BULONG|BIND,	/*[TLONG]*/
 	BINT|BUINT|BLONG|BULONG|BIND,	/*[TULONG]*/

src/cmd/8l/8.out.h

@@ -460,7 +460,7 @@ enum
 	T_SCONST	= 1<<5,
 	T_OFFSET2	= 1<<6,
 
-	REGARG		= 0,
+	REGARG		= -1,
 	REGRET		= D_AX,
 	FREGRET		= D_F0,
 	REGSP		= D_SP,

src/cmd/cc/pgen.c

@@ -83,7 +83,7 @@ codgen(Node *n, Node *nn)
 	/*
 	 * isolate first argument
 	 */
-	if(REGARG) {
+	if(REGARG >= 0) {
 		if(typesuv[thisfn->link->etype]) {
 			nod1 = *nodret->left;
 			nodreg(&nod, &nod1, REGARG);
@@ -385,8 +385,8 @@ loop:
 		gbranch(OGOTO);		/* entry */
 		sp = p;
 
-		/* 
-		 * if there are no incoming labels in the 
+		/*
+		 * if there are no incoming labels in the
 		 * body and the top's not reachable, warn
 		 */
 		if(!canreach && warnreach && deadheads(n)) {
@@ -410,7 +410,7 @@ loop:
 
 		patch(spc, pc);
 		gen(l->right->right);	/* inc */
-		patch(sp, pc);	
+		patch(sp, pc);
 		if(l->left != Z) {	/* test */
 			bcomplex(l->left, Z);
 			patch(p, breakpc);
@@ -460,7 +460,7 @@ loop:
 		 * Don't complain about unreachable break statements.
 		 * There are breaks hidden in yacc's output and some people
 		 * write return; break; in their switch statements out of habit.
-		 * However, don't confuse the analysis by inserting an 
+		 * However, don't confuse the analysis by inserting an
 		 * unreachable reference to breakpc either.
 		 */
 		if(!canreach)
@@ -488,7 +488,7 @@ loop:
 				canreach = 1;
 				gen(n->right->right);
 				/*
-				 * treat constant ifs as regular ifs for 
+				 * treat constant ifs as regular ifs for
 				 * reachability warnings.
 				 */
 				if(!canreach && oldreach && debug['w'] < 2)
@@ -501,7 +501,7 @@ loop:
 				canreach = 1;
 				supgen(n->right->right);
 				/*
-				 * treat constant ifs as regular ifs for 
+				 * treat constant ifs as regular ifs for
 				 * reachability warnings.
 				 */
 				if(!oldreach && canreach && debug['w'] < 2)