[Bug tree-optimization/78731] [5 Regression] Possible bug with switch when optimization is turned on.

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78731

Jeffrey A. Law <law at redhat dot com> changed:

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                 CC|                            |law at redhat dot com

--- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
I'm convinced that a table based jump threader that traverses backedges is
fundamentally a bad idea.  That's why I ripped it out and we rely on
Sebastian's code to handle those cases -- Sebastian's code doesn't have to deal
with table invalidation.

You might consider just disabling threading across the backedges.  There'll be
testsuite fallout, but in the end the layers upon layers of complexity to deal
with invalidation just isn't worth it.