[llvm] [SelectionDAG] Preserve volatile undef stores. (PR #99918)

[Matt Arsenault via llvm-commits]

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@@ -255,7 +255,7 @@ define amdgpu_kernel void @marked_kernel_use_other_sgpr(ptr addrspace(1) %ptr) #
   %queue.load = load volatile i8, ptr addrspace(4) %queue.ptr
   %implicitarg.load = load volatile i8, ptr addrspace(4) %implicitarg.ptr
   %dispatch.load = load volatile i8, ptr addrspace(4) %dispatch.ptr
-  store volatile i64 %dispatch.id, ptr addrspace(1) %ptr
+  store i64 %dispatch.id, ptr addrspace(1) %ptr
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arsenm wrote:

It's supposed to just be a dummy use. You could equally just remove the store, I guess 

https://github.com/llvm/llvm-project/pull/99918