[PATCH] D82614: ValueTracking: Fix isKnownNonZero for non-0 null pointers for byval

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:2379
+      // a check for the default address space. However, it seems some users are
+      // relying on this, so leave this as broken for now.
+      if (((A->hasPassPointeeByValueAttr() && PtrTy->getAddressSpace() == 0) ||
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LangRef says nonnnull means "not the value null", and the value null is an all-zero bit pattern.  That's maybe not ideal for some targets, sure, but I don't think there's a reason to call it out here specifically.  If we decide to change the meaning of the attributes in question, we'll audit all the users.


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:2380
+      // relying on this, so leave this as broken for now.
+      if (((A->hasPassPointeeByValueAttr() && PtrTy->getAddressSpace() == 0) ||
+           A->hasNonNullAttr()))
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Please use NullPointerIsDefined.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D82614/new/

https://reviews.llvm.org/D82614