llvm dev - Dec 2011 - [LLVMdev] Overlapping Allocas

Dear All,

Is there an optimization in the x86 back-end that could cause two 
alloca's to use overlapping memory?

-- John T.

On Fri, Dec 2, 2011 at 1:04 PM, John Criswell <criswell at illinois.edu>
wrote:
> Dear All,
>
> Is there an optimization in the x86 back-end that could cause two
> alloca's to use overlapping memory?
It's theoretically possible, but IIRC there isn't any such
optimization implemented at the moment.

-Eli

On 12/2/11 3:24 PM, Eli Friedman wrote:
> On Fri, Dec 2, 2011 at 1:04 PM, John Criswell<criswell at
illinois.edu>  wrote:
>> Dear All,
>>
>> Is there an optimization in the x86 back-end that could cause two
>> alloca's to use overlapping memory?
> It's theoretically possible, but IIRC there isn't any such
> optimization implemented at the moment.
Could the tail call optimization cause something like this?  If there's 
an alloca in a function and the function is called recursively, could 
tail call optimization cause all dynamic instances of the alloca to be 
allocated in the same place on the stack?

-- John T.
>
> -Eli