[llvm-commits] [llvm] r61934 - in /llvm/trunk: lib/Analysis/ValueTracking.cpp test/Transforms/InstCombine/2009-01-08-AlignAlloca.ll

[Chris Lattner]

On Jan 8, 2009, at 4:14 PM, Dan Gohman wrote:
>> No, this is just something that Evan noticed.  I don't know that it
>> actually manifested as a bug.
>
>
> This is actually a pretty significant language change.  With this
> commit, if front-ends want loads and stores from allocas to be done
> with preferred alignment, they have to add all the alignment
> directives manually. Previously, this just happened automatically.
>
> I think the previous behavior is more useful. It doesn't make a
> lot of sense to pretend that the allocas might not be allocated
> according to preferred alignment when they always are.

I don't agree. I would call this a deficiency in  
EnforceKnownAlignment.  EnforceKnownAlignment is the routine  
responsible for saying "hey I could speed stuff up by making this  
global be 16-byte aligned" etc.  Why not do it for allocas also?

-Chris