[PATCH] Improving LowerSwitch behavior for contiguous ranges

[Owen Anderson]

On Jun 10, 2014, at 11:37 AM, Hal Finkel <hfinkel at anl.gov> wrote:

>> 
>> Yep. Though I have to admit that it'd be nice if we had a range
>> propagation pass that would clean this up rather than special casing.
>> :\
> 
> Doesn't LVI do range propagation?


Sort of.

That said, range propagation isn’t a good solution to this problem.  SwitchLowering generally happens towards the end of a compilation pipeline, and you don’t want to run any significant set of CFG optimizations after it because they might re-introduce switches.

—Owen
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140610/a4ff9752/attachment.html>