https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109564
--- Comment #17 from Andrew Macleod <amacleod at redhat dot com> --- Created attachment 54893 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54893&action=edit new patch Alternatively, we can simply allow undefined SSA_NAMES to also be checked or single arguments like everything else. We were ignoring SSA_NAMEs that were UNDEFINED when it came to comparing arguments, which allows them to "ignored" basically. I kicked off a build with this patch but I am traveling today so may not be too timely. I think its should also fully resolve this. For the next release I was thinking about adding one way equivalences for PHIs.. or at leats treating ithis situation differently. that is looking like a better idea :-)
