5c, 5g: another attempt at silencing gcc

R=ken2
CC=golang-dev
https://golang.org/cl/4535074

src/cmd/5c/gc.h

@@ -69,7 +69,7 @@ struct	Adr
 
 	Sym*	sym;
 	char	type;
-	char	reg;
+	uchar	reg;
 	char	name;
 	char	etype;
 };
@@ -83,7 +83,7 @@ struct	Prog
 	Prog*	link;
 	int32	lineno;
 	char	as;
-	char	reg;
+	uchar	reg;
 	uchar	scond;
 };
 #define	P	((Prog*)0)

src/cmd/5c/peep.c

@@ -1100,7 +1100,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 		if(v->type == D_REG) {
 			if(v->reg <= REGEXT && v->reg > exregoffset)
 				return 2;
-			if(v->reg == REGARG)
+			if(v->reg == (uchar)REGARG)
 				return 2;
 		}
 		if(v->type == D_FREG)
@@ -1118,7 +1118,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 
 	case ATEXT:	/* funny */
 		if(v->type == D_REG)
-			if(v->reg == REGARG)
+			if(v->reg == (uchar)REGARG)
 				return 3;
 		return 0;
 	}

src/cmd/5g/gg.h

@@ -26,7 +26,7 @@ struct	Addr
 	int	width;
 	uchar	type;
 	char	name;
-	char	reg;
+	uchar	reg;
 	char pun;
 	uchar	etype;
 };
@@ -41,7 +41,7 @@ struct	Prog
 	Addr	to;		// dst address
 	Prog*	link;		// next instruction in this func
 	void*	regp;		// points to enclosing Reg struct
-	char	reg;		// doubles as width in DATA op
+	uchar	reg;		// doubles as width in DATA op
 	uchar	scond;
 };
 

src/cmd/5g/peep.c

@@ -1134,7 +1134,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 		if(v->type == D_REG) {
 			if(v->reg <= REGEXT && v->reg > exregoffset)
 				return 2;
-			if(v->reg == REGARG)
+			if(v->reg == (uchar)REGARG)
 				return 2;
 		}
 		if(v->type == D_FREG)
@@ -1152,7 +1152,7 @@ copyu(Prog *p, Adr *v, Adr *s)
 
 	case ATEXT:	/* funny */
 		if(v->type == D_REG)
-			if(v->reg == REGARG)
+			if(v->reg == (uchar)REGARG)
 				return 3;
 		return 0;
 	}