Hi Everyone,
I'm having trouble with floating point arithmetic and division by 0.
Undefined behavior sanitizer flags a division by 0 is a runtime error.
However, IEEE 754 says it is infinity if the operation does not trap.
(Assuming I am looking at the right version of the standard).
So to test IEEE floating point for division by 0:
void test_floats(void)
{
ASSERT(INFINITY == 1.0f / 0.0f);
...
}
It seems like a reasonable test to me. However, we don't really want
UBsan findings during testing either.
I was looking at pragmas to disable UBsan division-by-zero in the
source file, but I don't see one. Confer,
https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html and
https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html.
Given users will CFLAGS="-fsanitize=undefined", what is the way to
handle this in a way that avoids asking the user to do something?
Asking the user to RTFM and use something like
-fsanitize=all,no-divide-by-zero or
-fsanitize-recover=float-divide-by-zero is not going to work. If RTFM
was going to work, it would have happened in the last 50 years or so.
So I want to engineer around the user.
Jeff
