Messages in this thread Patch in this message | | | From | Richard Fitzgerald <> | Subject | [PATCH v2 1/2] lib: test_scanf: Remove pointless use of type_min() with unsigned types | Date | Tue, 25 May 2021 13:20:11 +0100 |
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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> --- lib/test_scanf.c | 13 ++++++------- 1 file 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; \ + if (value_representable_in_type(T, numbers[i])) \ + test_one_number(T, gen_fmt, scan_fmt, \ + numbers[i], fn); \ \ - 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); \ } \ -- 2.20.1
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