[Bug ipa/66424] wrong code at -O2 and -O3 on x86_64-linux-gnu in 32-bit mode

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66424

--- Comment #2 from Zhendong Su <su at cs dot ucdavis.edu> ---
Jakub, I'm not sure that the code is invalid. First, the type of p in fn1 is
defaulted to int. Second, all the invocations of fn1 from fn2 are with the same
argument 0LL, which int can represent. 

Also, none of ubsan, Frama-C, and CompCert's reference interpreter complains
about the code.