[LLVMdev] Stupid '-load-vn -licm' question (LLVM 1.6)

[Chris Lattner]

On Sat, 18 Mar 2006, Eric Kidd wrote:
> On Mar 17, 2006, at 12:19 PM, Chris Lattner wrote:
>> Great.  Note that -cee is a beta pass... it has some known bugs and isn't 
>> planned to be worked on in the immediate future. :(
>
> After a bit of digging, I found one open bug and two failing test cases, all 
> of which appear to be feature requests:
>
>  #217: LLVM needs a generic dominator update mechanism
>  nullpointer.ll: "a load or store of a pointer indicates that the pointer is 
> not null."
>  looptest.ll: "Note that this is a "feature" test, not a correctness test."

Yup.

> All the other test cases pass, and none of the other unassigned bugs mention 
> CEE. (I checked Bugzilla by hand--since searching for "correlated" doesn't 
> even find bug #217--so I might have missed something.) Google doesn't seem to 
> turn up anything, either.
>
> Does -cee actually produce incorrect code for some inputs? Or is it merely 
> incomplete?

As I mentioned on IRC, I don't really remember.  I thought it did 
miscompile some cases, but it has been too long for me to remember. 
Running it through llvm-test would be a good way to find out :)

> I'm looking for an optimizer pass to tweak (as a learning exercise), and if 
> -cee isn't too hairy, I'd be happy to add support for 'switch' instructions 
> and fix a few minor bugs. :-)

Sounds great!

-Chris

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