[polly] r246396 - Do not store into a temporary twine

[Tobias Grosser via llvm-commits]

On 08/31/2015 06:04 PM, David Blaikie wrote:
> On Sun, Aug 30, 2015 at 12:51 PM, Tobias Grosser via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: grosser
>> Date: Sun Aug 30 14:51:01 2015
>> New Revision: 246396
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=246396&view=rev
>> Log:
>> Do not store into a temporary twine
>>
>> For some reason, this causes memory corruption issues. Let's just avoid it.
>>
>
> Twines are not designed to be named, as such.
>
> A Twine expresion stores references to Twine subexpressions that are local
> to the C++ full expression - once you are outside that full expression
> those references are dangling (as the subexpression Twines are out of
> scope).

Thanks for explaining. I think I run into a similar issue a couple of months
ago. Unfortunately the code that showed the bug does not really give any hint
that this is indeed problematic:

auto Name = Address->getName() + ".reload";

I suppose there is no easy way for us to make this cause a compiler bug or
trigger an assert?

Best,
Tobias