[PATCH] D138991: [AAPointerInfo] handle multiple offsets in PHI

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added subscribers: ruiling, bogner.
arsenm added inline comments.


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Comment at: llvm/include/llvm/Transforms/IPO/Attributor.h:1091
+  Pass *LegacyPass = nullptr;
 };
 
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arsenm wrote:
> jdoerfert wrote:
> > arsenm wrote:
> > > jdoerfert wrote:
> > > > arsenm wrote:
> > > > > aeubanks wrote:
> > > > > > arsenm wrote:
> > > > > > > jdoerfert wrote:
> > > > > > > > Do we really need legacy PM support? I would prefer not to add complexity for it.
> > > > > > > Yes. Contrary to popular belief, the new PM is not complete. Until we have codegen support, we need legacy PM support for IR passes run in the backend
> > > > > > is it possible to run whatever pass you're interested in as part of the optimization pipeline?
> > > > > Not in the right place. We can't even move all the IR passes because of the one RegionPass which new PM doesn't have.
> > > > Shouldn't we invest the time and code to provide a "region pass wrapper"? We stopped testing most of these things with the old PM, using it is not a great idea.
> > > We should invest the time in killing of the structurizer entirely. It being a region pass is a problem for many reasons. But that's hard
> > @arsenm Where do I find that structurizer and what should the replacement do/look like? It's not https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Scalar/StructurizeCFG.cpp right?
> > 
> That is the one.
> 
> 
Trying to write a replacement structurizer is basically a rite of passage; many have tried and most have failed.

It needs to be a function pass. @ruiling was looking into writing a new one recently. @bogner may also have another implementation already


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https://reviews.llvm.org/D138991