diff --git a/check.t b/check.t
index c5e6b5d..87ab7e6 100644
--- a/check.t
+++ b/check.t
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.422 2011/03/12 23:06:41 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.423 2011/03/13 01:20:14 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -25,7 +25,7 @@
 # http://www.research.att.com/~gsf/public/ifs.sh
 
 expected-stdout:
-	@(#)MIRBSD KSH R39 2011/03/08
+	@(#)MIRBSD KSH R39 2011/03/12
 description:
 	Check version of shell.
 stdin:
@@ -6945,6 +6945,8 @@ description:
 stdin:
 	echo $(case 1 in (1) echo yes;; (2) echo no;; esac)
 	echo $(case 1 in 1) echo yes;; 2) echo no;; esac)
+	echo $(($(case 1 in (1) echo 1;; (*) echo 2;; esac)+10))
+	echo $(($(case 1 in 1) echo 1;; *) echo 2;; esac)+20))
 	TEST=1234; echo ${TEST: $(case 1 in (1) echo 1;; (*) echo 2;; esac)}
 	TEST=5678; echo ${TEST: $(case 1 in 1) echo 1;; *) echo 2;; esac)}
 	(( a = $(case 1 in (1) echo 1;; (*) echo 2;; esac) )); echo $a.
@@ -6952,6 +6954,8 @@ stdin:
 expected-stdout:
 	yes
 	yes
+	11
+	21
 	234
 	678
 	1.
@@ -6962,13 +6966,9 @@ description:
 	COMSUB inside SLETARRAY and SASPAREN/EXPRSUB
 expected-fail: yes
 stdin:
-	echo $(($(case 1 in (1) echo 1;; (*) echo 2;; esac)+10))
-	echo $(($(case 1 in 1) echo 1;; *) echo 2;; esac)+20))
 	a=($(case 1 in (1) echo 1;; (*) echo 2;; esac)); echo ${a[0]}.
 	a=($(case 1 in 1) echo 1;; *) echo 2;; esac)); echo ${a[0]}.
 expected-stdout:
-	11
-	21
 	1.
 	1.
 ---
diff --git a/edit.c b/edit.c
index aef48a7..a7b1b8f 100644
--- a/edit.c
+++ b/edit.c
@@ -25,7 +25,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.205 2011/03/07 20:30:35 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.206 2011/03/13 01:20:16 tg Exp $");
 
 /*
  * in later versions we might use libtermcap for this, but since external
@@ -1138,7 +1138,7 @@ x_emacs(char *buf, size_t len)
 		x_nextcmd = -1;
 	}
 	editmode = 1;
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		x_flush();
 		if ((c = x_e_getc()) < 0)
 			return (0);
@@ -1797,7 +1797,7 @@ x_search_hist(int c)
 	unsigned char f;
 
 	*p = '\0';
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		if (offset < 0) {
 			x_e_puts("\nI-search: ");
 			x_e_puts(pat);
@@ -3474,7 +3474,7 @@ x_vi(char *buf, size_t len)
 
 	editmode = 2;
 	x_flush();
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		if (macro.p) {
 			c = *macro.p++;
 			/* end of current macro? */
diff --git a/eval.c b/eval.c
index 438635e..6e69cdc 100644
--- a/eval.c
+++ b/eval.c
@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/eval.c,v 1.98 2011/03/12 23:06:43 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/eval.c,v 1.99 2011/03/13 01:20:17 tg Exp $");
 
 /*
  * string expansion
@@ -246,7 +246,7 @@ expand(const char *cp,	/* input word */
 	memset(&st_head, 0, sizeof(st_head));
 	st = &st_head;
 
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		Xcheck(ds, dp);
 
 		switch (type) {
diff --git a/exec.c b/exec.c
index 7b3a554..c6590fa 100644
--- a/exec.c
+++ b/exec.c
@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.87 2011/02/18 22:26:08 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.88 2011/03/13 01:20:18 tg Exp $");
 
 #ifndef MKSH_DEFAULT_EXECSHELL
 #define MKSH_DEFAULT_EXECSHELL	"/bin/sh"
@@ -336,7 +336,7 @@ execute(struct op * volatile t,
 		    (const char **)eval((const char **)t->vars,
 		    DOBLANK | DOGLOB | DOTILDE);
 		e->type = E_LOOP;
-		while (1) {
+		while (/* CONSTCOND */ 1) {
 			i = sigsetjmp(e->jbuf, 0);
 			if (!i)
 				break;
@@ -374,7 +374,7 @@ execute(struct op * volatile t,
 	case TWHILE:
 	case TUNTIL:
 		e->type = E_LOOP;
-		while (1) {
+		while (/* CONSTCOND */ 1) {
 			i = sigsetjmp(e->jbuf, 0);
 			if (!i)
 				break;
@@ -958,7 +958,7 @@ define(const char *name, struct op *t)
 	struct tbl *tp;
 	bool was_set = false;
 
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		tp = findfunc(name, hash(name), true);
 
 		if (tp->flag & ISSET)
@@ -1491,7 +1491,7 @@ do_selectargs(const char **ap, bool print_menu)
 
 	for (argct = 0; ap[argct]; argct++)
 		;
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		/*-
 		 * Menu is printed if
 		 *	- this is the first time around the select loop
diff --git a/funcs.c b/funcs.c
index 4b99303..94b3e26 100644
--- a/funcs.c
+++ b/funcs.c
@@ -38,7 +38,7 @@
 #endif
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.175 2011/03/07 20:30:37 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.176 2011/03/13 01:20:19 tg Exp $");
 
 #if HAVE_KILLPG
 /*
@@ -2172,7 +2172,7 @@ c_read(const char **wp)
 			if (c == delim || c == EOF)
 				break;
 			/* loop to read one character */
-			while (1) {
+			while (/* CONSTCOND */ 1) {
 				c = shf_getc(shf);
 				/* we break unless NUL or EOF, so... */
 				if (c == delim)
@@ -3636,7 +3636,7 @@ c_cat(const char **wp)
 				continue;
 			}
 		}
-		while (1) {
+		while (/* CONSTCOND */ 1) {
 			n = blocking_read(fd, (cp = buf), MKSH_CAT_BUFSIZ);
 			if (n == -1) {
 				if (errno == EINTR)
diff --git a/jobs.c b/jobs.c
index d763012..c0ef6b4 100644
--- a/jobs.c
+++ b/jobs.c
@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.76 2011/03/06 17:08:12 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.77 2011/03/13 01:20:20 tg Exp $");
 
 #if HAVE_KILLPG
 #define mksh_killpg		killpg
@@ -293,7 +293,7 @@ j_change(void)
 			setsig(&sigtraps[SIGTTIN], SIG_DFL,
 			    SS_RESTORE_ORIG|SS_FORCE);
 			/* wait to be given tty (POSIX.1, B.2, job control) */
-			while (1) {
+			while (/* CONSTCOND */ 1) {
 				pid_t ttypgrp;
 
 				if ((ttypgrp = tcgetpgrp(tty_fd)) < 0) {
@@ -1310,9 +1310,9 @@ j_sigchld(int sig MKSH_A_UNUSED)
 		check_job(j);
 	}
 #ifndef MKSH_NOPROSPECTOFWORK
-	    while (1);
+	    while (/* CONSTCOND */ 1);
 #else
-	    while (0);
+	    while (/* CONSTCOND */ 0);
 #endif
 }
 
diff --git a/main.c b/main.c
index aa4487f..5bc15ce 100644
--- a/main.c
+++ b/main.c
@@ -33,7 +33,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.179 2011/03/05 21:43:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.180 2011/03/13 01:20:21 tg Exp $");
 
 extern char **environ;
 
@@ -716,7 +716,7 @@ shell(Source * volatile s, volatile int toplevel)
 			/* NOTREACHED */
 		}
 	}
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		if (trap)
 			runtraps(0);
 
@@ -781,7 +781,7 @@ unwind(int i)
 		--trap_nested;
 		i = LLEAVE;
 	}
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		switch (e->type) {
 		case E_PARSE:
 		case E_FUNC:
diff --git a/misc.c b/misc.c
index 1c741db..b078d4e 100644
--- a/misc.c
+++ b/misc.c
@@ -29,7 +29,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.153 2011/03/07 20:30:39 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.154 2011/03/13 01:20:21 tg Exp $");
 
 /* type bits for unsigned char */
 unsigned char chtypes[UCHAR_MAX + 1];
@@ -1594,11 +1594,11 @@ unbksl(bool cstyle, int (*fg)(void), void (*fp)(int))
 		break;
 	case 'U':
 		i = 8;
-		if (0)
+		if (/* CONSTCOND */ 0)
 		/* FALLTHROUGH */
 	case 'u':
 		i = 4;
-		if (0)
+		if (/* CONSTCOND */ 0)
 		/* FALLTHROUGH */
 	case 'x':
 		i = cstyle ? -1 : 2;
diff --git a/sh.h b/sh.h
index eb829ba..516f929 100644
--- a/sh.h
+++ b/sh.h
@@ -154,9 +154,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.443 2011/03/12 23:04:47 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.444 2011/03/13 01:20:22 tg Exp $");
 #endif
-#define MKSH_VERSION "R39 2011/03/08"
+#define MKSH_VERSION "R39 2011/03/12"
 
 #ifndef MKSH_INCLUDES_ONLY
 
diff --git a/shf.c b/shf.c
index 2c9e782..06502f3 100644
--- a/shf.c
+++ b/shf.c
@@ -24,7 +24,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/shf.c,v 1.40 2010/09/14 21:26:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/shf.c,v 1.41 2011/03/13 01:20:23 tg Exp $");
 
 /* flags to shf_emptybuf() */
 #define EB_READSW	0x01	/* about to switch to reading */
@@ -420,7 +420,7 @@ shf_fillbuf(struct shf *shf)
 	shf->flags |= SHF_READING;
 
 	shf->rp = shf->buf;
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		n = blocking_read(shf->fd, (char *)shf->buf, shf->rbsize);
 		if (n < 0 && errno == EINTR && !(shf->flags & SHF_INTERRUPT))
 			continue;
diff --git a/syn.c b/syn.c
index 6db6132..75f4b99 100644
--- a/syn.c
+++ b/syn.c
@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/syn.c,v 1.55 2011/03/12 20:20:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/syn.c,v 1.56 2011/03/13 01:20:24 tg Exp $");
 
 struct nesting_state {
 	int start_token;	/* token than began nesting (eg, FOR) */
@@ -66,7 +66,7 @@ static int symbol;			/* yylex value */
 #define ACCEPT		(reject = false)
 #define token(cf)	((reject) ? (ACCEPT, symbol) : (symbol = yylex(cf)))
 #define tpeek(cf)	((reject) ? (symbol) : (REJECT, symbol = yylex(cf)))
-#define musthave(c,cf)	do { if (token(cf) != (c)) syntaxerr(NULL); } while (0)
+#define musthave(c,cf)	do { if (token(cf) != (c)) syntaxerr(NULL); } while (/* CONSTCOND */ 0)
 
 static void
 yyparse(void)
@@ -128,7 +128,7 @@ c_list(bool multi)
 	int c;
 	bool have_sep;
 
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		p = andor();
 		/*
 		 * Token has always been read/rejected at this point, so
@@ -256,7 +256,7 @@ get_command(int cf)
 		syniocf &= ~(KEYWORD|ALIAS);
 		t = newtp(TCOM);
 		t->lineno = source->line;
-		while (1) {
+		while (/* CONSTCOND */ 1) {
 			cf = (t->u.evalflags ? ARRAYVAR : 0) |
 			    (XPsize(args) == 0 ? ALIAS|VARASN : CMDWORD);
 			switch (tpeek(cf)) {
diff --git a/tree.c b/tree.c
index 0ec5f59..c8712ae 100644
--- a/tree.c
+++ b/tree.c
@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/tree.c,v 1.39 2011/03/12 23:04:48 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/tree.c,v 1.40 2011/03/13 01:20:24 tg Exp $");
 
 #define INDENT	8
 
@@ -279,7 +279,7 @@ tputS(const char *wp, struct shf *shf)
 	 *	OQUOTE ["'] ... CQUOTE ["']
 	 *	COMSUB [(`] ...\0	(handle $ ` \ and maybe " in `...` case)
 	 */
-	while (1)
+	while (/* CONSTCOND */ 1)
 		switch (*wp++) {
 		case EOS:
 			return;
@@ -515,7 +515,7 @@ wdscan(const char *wp, int c)
 {
 	int nest = 0;
 
-	while (1)
+	while (/* CONSTCOND */ 1)
 		switch (*wp++) {
 		case EOS:
 			return (wp);
@@ -590,7 +590,7 @@ wdstrip_internal(struct shf *shf, const char *wp, bool keepq, bool make_magic)
 	 *	x${foo:-"hi"} -> x${foo:-hi}
 	 *	x${foo:-'hi'} -> x${foo:-hi} unless keepq
 	 */
-	while (1)
+	while (/* CONSTCOND */ 1)
 		switch (*wp++) {
 		case EOS:
 			return;
@@ -799,7 +799,7 @@ dumpwdvar(struct shf *shf, const char *wp)
 {
 	int c, quotelevel = 0;
 
-	while (1) {
+	while (/* CONSTCOND */ 1) {
 		switch(*wp++) {
 		case EOS:
 			shf_puts("EOS", shf);
diff --git a/var.c b/var.c
index 5133978..0a48928 100644
--- a/var.c
+++ b/var.c
@@ -26,7 +26,7 @@
 #include <sys/sysctl.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/var.c,v 1.117 2011/03/07 20:30:41 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/var.c,v 1.118 2011/03/13 01:20:25 tg Exp $");
 
 /*
  * Variables
@@ -910,7 +910,7 @@ skip_wdvarname(const char *s,
 			char c;
 			int depth = 0;
 
-			while (1) {
+			while (/* CONSTCOND */ 1) {
 				if (p[0] != CHAR)
 					break;
 				c = p[1];