[llvm-commits] [llvm] r50382 - in /llvm/trunk: include/llvm/LinkAllPasses.h include/llvm/Transforms/Scalar.h lib/Transforms/Scalar/DeadLoopElimination.cpp

[Chris Lattner]

On Apr 29, 2008, at 1:22 PM, Owen Anderson wrote:

>
> On Apr 29, 2008, at 1:36 PM, Chris Lattner wrote:
>>> +  for (Loop::block_iterator LI = L->block_begin(), LE = L-
>>>> block_end();
>>> +       LI != LE; ++LI) {
>>> +    for (BasicBlock::iterator BI = (*LI)->begin(), BE = (*LI)- 
>>> >end();
>>> +         BI != BE; ) {
>>> +      Instruction* I = BI++;
>>> +      I->eraseFromParent();
>>> +    }
>>> +
>>> +    (*LI)->eraseFromParent();
>>> +  }
>>
>> You are incrementing LI after you erase *LI.
>
> I'm actually reasonably confident that this is safe.  I'm iterating  
> over the loop's block list, not over the function ilist.  Erasing  
> *LI doesn't remove LI from the loop's block list, it just makes it a  
> pointer to freed memory.  You'll note that the next step is to  
> remove the blocks from LoopInfo, which does remove them from the  
> loop's block list, and from the block lists of any parent loops as  
> well.

You're right, thanks!

-Chris
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20080429/92ead614/attachment.html>