On Mon, 28 Apr 2014, Marek Polacek wrote:
This patch implements -fsanitize=float-divide-by-zero option that can be used to detect division by zero even when using floating types. Most of the code in ubsan_instrument_division was ready for this so this was mainly about handling REAL_TYPE there.
Ideally this would all be unneeded, you would compile your program with pragma stdc fenv_access on, on glibc you would call feenableexcept(FE_DIVBYZERO) at the beginning of the program, done (I may have listed the wrong function, I am always confused by those names).
But I guess we won't be there anytime soon, so in the mean time...
Since division by a floating point zero can be a valid way of obtaining infinities and NaNs, I'm not 100% sure this ought to be enabled by default (that is, enabled when -fsanitize=undefined is specified).
Please don't enable it with "undefined". As you say, it is well defined (except when finite-math-only is in effect). If you want a meta-category for this kind of valid thing, maybe -fsanitize=unusual or -fsanitize=suspicious.
-- Marc Glisse
