tree-optimization/108076 - if-conversion and forced labels
When doing if-conversion we simply throw away labels without checking
whether they are possibly targets of non-local gotos or have their
address taken. The following rectifies this and refuses to if-convert
such loops.
PR tree-optimization/108076
* tree-if-conv.cc (if_convertible_loop_p_1): Reject blocks
with non-local or forced labels that we later remove
labels from.
* gcc.dg/torture/pr108076.c: New testcase.
(cherry picked from commit
b4fddbe9592e9feb37ce567d90af822b75995531)