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authorRichard Fitzgerald <rf@opensource.cirrus.com>2021-05-25 13:20:11 +0100
committerPetr Mladek <pmladek@suse.com>2021-05-27 15:38:03 +0200
commit1b932689c77766b68e2ead51ca0fb84ec5bb8965 (patch)
tree21122208e0a00f3c39c351bbf8d6b0df2fe6b853 /lib/test_scanf.c
parentef04d4ff4b19628c78abddc768acce097d35d086 (diff)
downloadlinux-1b932689c77766b68e2ead51ca0fb84ec5bb8965.tar.gz
lib: test_scanf: Remove pointless use of type_min() with unsigned types
sparse was producing warnings of the form:

 sparse: cast truncates bits from constant value (ffff0001 becomes 1)

There is no actual problem here. Using type_min() on an unsigned type
results in an (expected) truncation.

However, there is no need to test an unsigned value against type_min().
The minimum value of an unsigned is obviously 0, and any value cast to
an unsigned type is >= 0, so for unsigneds only type_max() need be tested.

This patch also takes the opportunity to clean up the implementation of
simple_numbers_loop() to use a common pattern for the positive and
negative test.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210525122012.6336-2-rf@opensource.cirrus.com
Diffstat (limited to 'lib/test_scanf.c')
-rw-r--r--lib/test_scanf.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/lib/test_scanf.c b/lib/test_scanf.c
index 8d577aec6c28..48ff5747a4da 100644
--- a/lib/test_scanf.c
+++ b/lib/test_scanf.c
@@ -187,8 +187,8 @@ static const unsigned long long numbers[] __initconst = {
 #define value_representable_in_type(T, val)					 \
 (is_signed_type(T)								 \
 	? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \
-	: ((unsigned long long)(val) >= type_min(T)) &&				 \
-	  ((unsigned long long)(val) <= type_max(T)))
+	: ((unsigned long long)(val) <= type_max(T)))
+
 
 #define test_one_number(T, gen_fmt, scan_fmt, val, fn)			\
 do {									\
@@ -204,12 +204,11 @@ do {									\
 	int i;								\
 									\
 	for (i = 0; i < ARRAY_SIZE(numbers); i++) {			\
-		if (!value_representable_in_type(T, numbers[i]))	\
-			continue;					\
-									\
-		test_one_number(T, gen_fmt, scan_fmt, numbers[i], fn);	\
+		if (value_representable_in_type(T, numbers[i]))		\
+			test_one_number(T, gen_fmt, scan_fmt,		\
+					numbers[i], fn);		\
 									\
-		if (is_signed_type(T))					\
+		if (value_representable_in_type(T, -numbers[i]))	\
 			test_one_number(T, gen_fmt, scan_fmt,		\
 					-numbers[i], fn);		\
 	}								\