[Bug tree-optimization/67328] range test rather than single bit test for code testing enum values

[amodra at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67328

--- Comment #1 from Alan Modra <amodra at gmail dot com> ---
Created attachment 36247
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36247&action=edit
testcase from binutils/include/bfdlink.h