[clang] [InstCombine] Add combines/simplifications for `llvm.ptrmask` (PR #67166)

[Nikita Popov via cfe-commits]

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@@ -143,7 +155,7 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     return SimplifyMultipleUseDemandedBits(I, DemandedMask, Known, Depth, CxtI);
 
   KnownBits LHSKnown(BitWidth), RHSKnown(BitWidth);
-
+  bool MaySimplifyAsConstant = true;
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nikic wrote:

Possibly this flag can be replaced by a isPointerTy check below? This seems like it should also hold for other instructions working on pointers, if we were to handle them.

https://github.com/llvm/llvm-project/pull/67166