Fixed the handling of "while (0) {}".

It's a corner case; but, conditional macroes might create it -- better safe than sorry.

test/val/while.c

@@ -1,53 +1,107 @@
 /*
-  !!DESCRIPTION!!
+  !!DESCRIPTION!! while-condition tests
   !!ORIGIN!!      SDCC regression tests
   !!LICENCE!!     GPL, read COPYING.GPL
 */
 
 #include <stdio.h>
-#include <limits.h>
 
-unsigned char success = 0;
-unsigned char failures = 0;
-unsigned char dummy = 0;
+static unsigned char failures = 0x00;
+static unsigned char achar0 = 0;
 
-#ifdef SUPPORT_BIT_TYPES
-bit bit0 = 0;
-#endif
-unsigned int aint0 = 0;
-unsigned int aint1 = 0;
-unsigned char achar0 = 0;
-unsigned char achar1 = 0;
-
-void
-done ()
-{
-  dummy++;
-}
-
-void
+static void
 while1 (void)
 {
   unsigned char i = 10;
 
-  do
-    {
-      achar0++;
-    }
-  while (--i);
+  do {
+    ++achar0;
+  } while (--i);
 
-  if (achar0 != 10)
-    failures++;
+  if (achar0 != 10) {
+    failures |= 0x01;
+  }
+}
+
+static void
+while2 (void)
+{
+  unsigned char i = 10;
+
+  achar0 = 0;
+  while (--i) {
+    ++achar0;
+  }
+
+  if (achar0 != 10 - 1) {
+    failures |= 0x02;
+  }
+}
+
+static void
+while3 (void)
+{
+  achar0 = 0;
+  do {
+    if (++achar0 == (unsigned char)0) {
+      return;
+    }
+  } while (1);
+
+  failures |= 0x04;
+}
+
+static void
+while4 (void)
+{
+  achar0 = 0;
+  while (1) {
+    if (++achar0 == (unsigned char)0) {
+      return;
+    }
+  }
+
+  failures |= 0x08;
+}
+
+static void
+while5 (void)
+{
+  achar0 = 0;
+  do {
+    ++achar0;
+  } while (0);
+
+  if (achar0 != 1) {
+    failures |= 0x10;
+  }
+}
+
+static void
+while6 (void)
+{
+  achar0 = 0;
+  while (0) {
+    ++achar0;
+  }
+
+  if (achar0 != 1 - 1) {
+    failures |= 0x20;
+  }
 }
 
 int
 main (void)
 {
   while1 ();
+  while2 ();
+  while3 ();
+  while4 ();
+  while5 ();
+  while6 ();
 
-  success = failures;
-  done ();
-  printf("failures: %d\n",failures);
-
+  if (failures) {
+    printf("failures: 0x%02X\n", failures);
+  }
   return failures;
 }