[PATCH] D78765: [TRE] Fix bug in handling of switch statements

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

In general, I think it has to look something like that, yes.  You have to keep the value from the first iteration in a PHI node like %accumulator.tr.  You need a select in the loop to consistently take the value from the first iteration.  And you need a select before the return to check if there's a valid value in %accumulator.tr.  Otherwise, the dominance doesn't work out in general, and you're back in isDynamicConstant() territory.  Later loop optimizations should be able to simplify it to something sane in most cases.


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https://reviews.llvm.org/D78765