[PATCH] D32423: Constant fold barriers of null and undef

[Piotr Padlewski via Phabricator via llvm-commits]

Prazek added inline comments.


================
Comment at: lib/Analysis/ConstantFolding.cpp:1779-1783
+    if (isa<ConstantPointerNull>(Operands[0])) {
+      if (IntrinsicID == Intrinsic::invariant_group_barrier)
         return Operands[0];
       return nullptr;
     }
----------------
majnemer wrote:
> Isn't this only valid if the address space is zero?
True, but can you pass pointer from another addrspace to invariant.group.barrier?

When I try
  %X = addrspacecast i8* null to i8 addrspace(1)*
  %b2 = call i8* @llvm.invariant.group.barrier(i8* %X)

I get
   error: '%X' defined with type 'i8 addrspace(1)*'

I could add this line:
  cast<PointerType>(Operands[0]->getType())->getAddressSpace() == 0
but I won't be able to test it in any way if I am not wrong.



https://reviews.llvm.org/D32423