[llvm-bugs] [Bug 27296] LVI should understand conditional branches where the condition is a conjunction or disjunction

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=27296

John Regehr <regehr at cs.utah.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |WORKSFORME

--- Comment #5 from John Regehr <regehr at cs.utah.edu> ---
Well.... I made a fix for this which intersected any constant ranges found in a
tree of and instructions on taken branch of a conditional, and in a tree of or
instructions found on the false branch of a conditional. This logic fires a lot
but the increase in precision is very unimpressive and so are the resulting
optimizations. For example across all of SPEC CINT 2006 the binary size is
reduced by a few hundred bytes as a result of the added LVI precision. So
overall the benefit of this patch doesn't seem to outweigh the extra
complexity.

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