We'd call gen_shrink_wrap_conditions for functions that it can't handle
but edom_only_function can.

Tested on x86_64-linux-gnu.

gcc/
	PR tree-optimization/68474
	* tree-call-cdce.c (use_internal_fn): Protect call to
	gen_shrink_wrap_conditions.

gcc/testsuite/
	PR tree-optimization/68474
	* gcc.dg/pr68474.c: New test.

From-SVN: r231115