https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94337
--- Comment #4 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> --- (In reply to Vincent Lefèvre from comment #3) > * If the effective type remains the same (a union), then using any pointer > cast to another type would be invalid, but this could be unintuitive and > break a lot of code (and GCC should have emitted a warning for both printf > lines). Well, not the pointer cast itself, but an access to the memory after a conversion of the pointer type (even in the case where the pointer type matches the type of the member, as in ((struct s2 *) u.m2)->b). Note: the code example is derived from experimental GNU MPFR code (ubf2 branch) as an attempt to avoid aliasing issues in the current code without breaking the API or introducing drawbacks.
