[Bug sanitizer/81387] UBSAN consumes too much memory at -O2

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81387

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Just for curiosity, I tried to use clang++ 4.0.0 and clang++ pr81387.ii -c -O2
-fsanitize=undefined took me about 180s and memory was ~2.5GB.