8 Dec 05 notes from GCC improvement for Itanium conference call

[Chris Lattner]

On Dec 16, 2005, at 11:47 AM, Daniel Berlin wrote:

> On Fri, 2005-12-16 at 11:27 -0800, Chris Lattner wrote:
>> On Dec 16, 2005, at 11:15 AM, Mark K. Smith wrote:
>>> Additionally to the obstacles to adopt LLVM mentioned by Diego, I
>>> named usage of C++ (although it has advantages too) and patents.  
>>> LLVM
>>> should be checked for usage of compiler patents. Gcc people avoided
>>> many patents especially from Microsoft. We can not be sure right now
>>> about LLVM.
>>
>> The confusion is basically centered around the distinction between my
>> PhD research work and LLVM itself.
>> The thesis work I did at UIUC does relate closely to Steensgaard's
>> pointer analysis work, which is patented by Microsoft.  However, this
>> thesis work is not currently used by LLVM, and certainly won't be
>> incorporated directly into GCC (for obvious patent reasons), so this
>> isn't an issue with LLVM adoption by GCC.
>
> The sad fact is it probably doesn't matter if it's actually run by
> default or not.  It is built into the binary, exists in the source  
> tree,
> and *can be run* by simply passing a command line option to opt.

That's the thing.  opt isn't part of the C/C++ compiler.  This stuff  
isn't built into the binary, and cannot be run by passing an option  
to the C compiler.  It does exist in the (LLVM) source tree, but if  
that's an issue, it can be remedied.

> This invariably counts as a "making of the patented invention", and is
> considered infringement, even if it's not run by default.
> If you made it not built into the binary, you would be on more solid
> legal ground (but even then they'd still sue you anyway :P).

It's not built into the binary.  Again, 'opt' is a developer tool and  
not part of the C/C++ front-end (the front-end never invokes opt, etc).

However, I am certainly not a lawyer and defer to those who are :).   
If people would be more comfortable with the code out of the *llvm*  
distro, I can remove it, just let me know.  In any case, this issue  
still has nothing to do with GCC integration.

-Chris