Oh, I see. But this is kind of like punting the problem to the user :( The compiler should really generate code that raises an exception (just like in the case of 1/0).
On Saturday, January 30, 2021 at 7:04:22 PM UTC-5 Elronnd _ wrote: > On Sat, 30 Jan 2021, gmhwxi wrote: > > > Without -O2, the executable generated by gcc returns 32. With -O2, it is > > a non-terminating loop. Clearly, gcc assumes (with -O2) that the sum of > > two positive integers is also positive (but it is obviously false when > > modulo arithmetic is involved). BTW, clang does NOT have this issue. > > It's actually not a bug! > > In c, signed integer overflow is considered undefined behaviour, so the > compiler is free to treat is as nonterminating instead of wrapping. And > in fact, my version of clang (11.0.1) returns 33 for that function. > > If you want the compiler to treat integer overflow as wrapping, you have > to pass it -fwrapv. > > -E > -- You received this message because you are subscribed to the Google Groups "ats-lang-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to ats-lang-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/ats-lang-users/685bc21f-43b5-4915-b3c7-9b05deef910cn%40googlegroups.com.
