[PATCH] D88684: llvm-reduce: Don't replace intrinsic calls with undef

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

In D88684#2317697 <https://reviews.llvm.org/D88684#2317697>, @arsenm wrote:

> In D88684#2317657 <https://reviews.llvm.org/D88684#2317657>, @dblaikie wrote:
>
>> what sort of problems manifest from this issue? Does it lead to slower reductions because they spend more time creating a lot of broken reductions?
>
> I think the general strategy of hack on the IR and if it breaks, skip it is a bit insane to begin with, so from that front this reduces the number of times that triggers

+1.

There are plenty of other similar cases, like `llvm.used` metadata which we should probably handle in a special way.



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Comment at: llvm/tools/llvm-reduce/deltas/ReduceFunctions.cpp:33
   copy_if(Program->functions(), std::back_inserter(FuncsToRemove),
-          [&O](auto &unused) { return !O.shouldKeep(); });
+          [&O](Function &F) { return !F.isIntrinsic() && !O.shouldKeep(); });
 
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I think a comment here would be good explaining why we exclude intrinsics. Also, should we also remove intrinsics from chunks to start with, to keep the numbering/chunk management consistent?


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https://reviews.llvm.org/D88684