[Bug tree-optimization/107569] [13 Regression] Failure to optimize std::isfinite since r13-3596

[pilarlatiesa at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107569

--- Comment #14 from Pilar Latiesa <pilarlatiesa at gmail dot com> ---
I have tested the testcase in comment #1 with Clang, and I realized that Clang
trunk avoids the tailcall to sqrt even without any hint with
__builtin_unreachable: https://godbolt.org/z/5sb8bYcoq 

Clang is somehow smart enough to realize that dot(u, u) is always non-negative.