timeutil: timespec: mitigate warnings when -Wtype-limits is used

Previously, warnings could be promoted to errors in timeutil.h. Those
warnings were of the form below.

warning: comparison is always true due to limited range of data type
warning: comparison is always false due to limited range of data type

Specifically, in the speed-optimized version of timespec_normalize() and
in the macro SYS_TICKS_TO_NSECS().

The speed-optimized version of timespec_normalize(), which used the
__builtin_add_overflow() function, was mainly intended to be branchless.
However, many targets generate branching instructions regardless.

The speed optimized version is less valuable in that case, so remove it.

Additionally, SYS_TICKS_TO_NSECS() does not generate the above warnings
when k_ticks_to_ns_floor64() is used instead of k_ticks_to_ns_floor32(),
so use the former.

Signed-off-by: Chris Friedt <[email protected]>

Author: cfriedt

include/zephyr/sys/timeutil.h

@@ -53,7 +53,7 @@ extern "C" {
 #define SYS_TICKS_TO_NSECS(ticks)                                                                  \
 	(((uint64_t)(ticks) >= (uint64_t)K_TICKS_FOREVER)                                          \
 		 ? (NSEC_PER_SEC - 1)                                                              \
-		 : k_ticks_to_ns_floor32((uint64_t)(ticks) % CONFIG_SYS_CLOCK_TICKS_PER_SEC))
+		 : k_ticks_to_ns_floor64((uint64_t)(ticks) % CONFIG_SYS_CLOCK_TICKS_PER_SEC))
 
 /* Define a timespec */
 #define SYS_TIMESPEC(sec, nsec)                                                                    \
@@ -419,36 +419,6 @@ static inline bool timespec_normalize(struct timespec *ts)
 {
 	__ASSERT_NO_MSG(ts != NULL);
 
-#if defined(CONFIG_SPEED_OPTIMIZATIONS) && HAS_BUILTIN(__builtin_add_overflow)
-
-	int64_t sec = 0;
-	int sign = (ts->tv_nsec >= 0) - (ts->tv_nsec < 0);
-
-	/* only one of the following should be non-zero */
-	sec += (ts->tv_nsec >= (long)NSEC_PER_SEC) * (ts->tv_nsec / (long)NSEC_PER_SEC);
-	sec += ((sizeof(ts->tv_nsec) != sizeof(int64_t)) && (ts->tv_nsec != LONG_MIN) &&
-		(ts->tv_nsec < 0)) *
-	       DIV_ROUND_UP((unsigned long)-ts->tv_nsec, (long)NSEC_PER_SEC);
-	sec += ((sizeof(ts->tv_nsec) == sizeof(int64_t)) && (ts->tv_nsec != INT64_MIN) &&
-		(ts->tv_nsec < 0)) *
-	       DIV_ROUND_UP((uint64_t)-ts->tv_nsec, NSEC_PER_SEC);
-	sec += ((sizeof(ts->tv_nsec) != sizeof(int64_t)) && (ts->tv_nsec == LONG_MIN)) *
-	       ((LONG_MAX / NSEC_PER_SEC) + 1);
-	sec += ((sizeof(ts->tv_nsec) == sizeof(int64_t)) && (ts->tv_nsec == INT64_MIN)) *
-	       ((INT64_MAX / NSEC_PER_SEC) + 1);
-
-	ts->tv_nsec -= sec * sign * NSEC_PER_SEC;
-
-	bool overflow = __builtin_add_overflow(ts->tv_sec, sign * sec, &ts->tv_sec);
-
-	if (!overflow) {
-		__ASSERT_NO_MSG(timespec_is_valid(ts));
-	}
-
-	return !overflow;
-
-#else
-
 	long sec;
 
 	if (ts->tv_nsec >= (long)NSEC_PER_SEC) {
@@ -489,7 +459,6 @@ static inline bool timespec_normalize(struct timespec *ts)
 	__ASSERT_NO_MSG(timespec_is_valid(ts));
 
 	return true;
-#endif
 }
 
 /**