[PATCH] Don't create instructions in CFLAliasAnalysis. NFC

[Pete Cooper]

Thanks George!  r239616.

Pete
> On Jun 10, 2015, at 11:51 PM, George Burgess IV <george.burgess.iv at gmail.com> wrote:
> 
> LGTM
> 
> - George
> 
>> On Jun 11, 2015, at 1:24 AM, Pete Cooper <peter_cooper at apple.com> wrote:
>> 
>> Hi Hal, George
>> 
>> The CFLAA code currently calls ConstantExpr::getAsInstruction which creates an instruction from a constant expr.
>> 
>> We then pass that instruction to the InstVisitor to analyze it.
>> 
>> Its not necessary to create these instructions as we can just cast from Constant to Operator in the visitor.  This is how other InstVisitor’s such as SelectionDAGBuilder handle ConstantExpr.
>> 
>> This should provide a small speed improvement to this pass, but i’m actually doing this as an effort to devirtualize Value.  This just happened to come up in that patch sequence.
>> 
>> Cheers,
>> Pete
>> 
>> <cfl.patch>