[llvm-commits] [Review request] Natural loop computation speedup

[Cameron Zwarich]

On Nov 30, 2010, at 5:24 AM, Duncan Sands wrote:

> Hi Cameron,
> 
>> This was a 16% speedup running loops on test-suite + SPEC2000.
> 
> dense map iterators are invalidated when new values are inserted.  Did you
> audit the code to check that this is not a problem?  If in doubt, you could
> build LLVM with expensive checks enabled and check that nothing blows up in
> the testsuite.

There are no iterators actually used for iteration (except in #if 0 code, and that one is fine), only for find() and only internal to LoopInfo, so it should be fine. Are there any expensive checks that invalidated iterators are not being used? I don't see them in DenseMap.h.

Cameron