llvm dev - Sep 2017 - Manipulate Register allocation in basic block level

Hi,
Is it possible to annotate basic blocks in order to manipulate them in
LLVM backend with fine granularity?

 Eg: I want to reserve registers for some parts of the code, therefore
need to stop register allocator from using some registers only in
specific basic blocks.

Thanks
Nisal

Hi Nisal,

We didn’t have any use case for this kind of things, so no, we don’t have
anything to do that.

What you could do is split the live-ranges you are interested in in the place
you care and use TargetRegisterInfo::getRegAllocationHints to bias the
allocation the way you want.

Cheers,
-Quentin
> On Sep 5, 2017, at 6:09 AM, Nisal Menuka via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> Hi,
> Is it possible to annotate basic blocks in order to manipulate them in
> LLVM backend with fine granularity?
> 
> Eg: I want to reserve registers for some parts of the code, therefore
> need to stop register allocator from using some registers only in
> specific basic blocks.
> 
> Thanks
> Nisal
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> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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