[llvm-dev] Questions about jump threading optimization and what we can do

Karl Rehm via llvm-dev
Thu, 30 Jan 2020 23:46:45 -0000

Since the bug report here: https://bugs.llvm.org/show_bug.cgi?id=44679 I've
been thinking about cases like it, such as: https://godbolt.org/z/Fwq8mn

I wonder what we can do about this in a general sense. As far as I can
tell, the jump threading algorithm is *really* conservative, which is one
reason this isn't working as well as I'd hope; however, we don't
want to
produce irreducible control flow that the other passes would work less
effectively on. Thoughts?

- Karl
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