diff --git a/os/oslib/src/chfactory.c b/os/oslib/src/chfactory.c
index 6ceda1c28..8490026c7 100644
--- a/os/oslib/src/chfactory.c
+++ b/os/oslib/src/chfactory.c
@@ -85,13 +85,14 @@ objects_factory_t ch_factory;
 
 static void copy_name(const char *sp, char *dp) {
   unsigned i;
+  char c;
 
-  i = 0U;
-  while ((*sp != (char)0) && (i++ < CH_CFG_FACTORY_MAX_NAMES_LENGTH)) {
-    *dp = *sp;
-    sp++;
-    dp++;
-  }
+  i = CH_CFG_FACTORY_MAX_NAMES_LENGTH;
+  do {
+    c = *sp++;
+    *dp++ = c;
+    i--;
+  } while ((c != (char)0) && (i > 0U));
 }
 
 static inline void dyn_list_init(dyn_list_t *dlp) {
diff --git a/os/rt/include/chregistry.h b/os/rt/include/chregistry.h
index b67dda4b6..ef03c9f4c 100644
--- a/os/rt/include/chregistry.h
+++ b/os/rt/include/chregistry.h
@@ -83,7 +83,7 @@ typedef struct {
 #define REG_REMOVE(tp) do {                                                 \
   (tp)->older->newer = (tp)->newer;                                         \
   (tp)->newer->older = (tp)->older;                                         \
-} while (0)
+} while (false)
 
 /**
  * @brief   Adds a thread to the registry list.
@@ -97,7 +97,7 @@ typedef struct {
   (tp)->older = (oip)->rlist.older;                                         \
   (tp)->older->newer = (tp);                                                \
   (oip)->rlist.older = (tp);                                                \
-} while (0)
+} while (false)
 
 /*===========================================================================*/
 /* External declarations.                                                    */
diff --git a/os/rt/src/chschd.c b/os/rt/src/chschd.c
index 6ea32a77d..23a739f08 100644
--- a/os/rt/src/chschd.c
+++ b/os/rt/src/chschd.c
@@ -90,7 +90,6 @@ static void __idle_thread(void *p) {
  *
  * @notapi
  */
-__attribute__((noinline))
 static thread_t *__sch_ready_behind(os_instance_t *oip, thread_t *tp) {
 
   chDbgAssert((tp->state != CH_STATE_READY) &&
@@ -125,7 +124,6 @@ static thread_t *__sch_ready_behind(os_instance_t *oip, thread_t *tp) {
  *
  * @notapi
  */
-__attribute__((noinline))
 static thread_t *__sch_ready_ahead(os_instance_t *oip, thread_t *tp) {
 
   chDbgAssert((tp->state != CH_STATE_READY) &&
@@ -725,7 +723,7 @@ thread_t *chSchSelectFirstI(void) {
   }
 
   /* Placing in ready list ahead of peers.*/
-  __sch_ready_ahead(oip, otp);
+  (void) __sch_ready_ahead(oip, otp);
 
   return ntp;
 }
diff --git a/os/rt/src/chvt.c b/os/rt/src/chvt.c
index 8ff465a76..24231deaf 100644
--- a/os/rt/src/chvt.c
+++ b/os/rt/src/chvt.c
@@ -60,6 +60,7 @@ static inline bool is_vtlist_empty(delta_list_t *dlhp) {
   return (bool)(dlhp == dlhp->next);
 }
 
+#if (CH_CFG_ST_TIMEDELTA > 0) || defined(__DOXYGEN__)
 /**
  * @brief   Last timer in the list check.
  *
@@ -99,7 +100,6 @@ static inline bool is_timer(delta_list_t *dlhp, delta_list_t *dlp) {
   return (bool)(dlp != dlhp);
 }
 
-#if (CH_CFG_ST_TIMEDELTA > 0) || defined(__DOXYGEN__)
 /**
  * @brief   Delta list compression.
  *
@@ -504,7 +504,7 @@ systimestamp_t chVTGetTimeStampI(void) {
   /* Interval between the last time stamp and current time used for a new
      time stamp. Note that this fails if the interval is larger than a
      systime_t type.*/
-  stamp = last + (systimestamp_t)chTimeDiffX((sysinterval_t)last, now);
+  stamp = last + (systimestamp_t)chTimeDiffX((systime_t)last, now);
 
   chDbgAssert(ch.vtlist.laststamp <= stamp, "wrapped");