[llvm] [GlobalISel] Preserve volatile and atomic undef/poison stores (PR #200099)

[Matt Arsenault via llvm-commits]

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@@ -542,8 +542,20 @@ static bool loadStoreBitcastWorkaround(const LLT Ty) {
   return EltSize != 32 && EltSize != 64;
 }
 
+// True for a pointer in an address space beyond the known AMDGPU address
+// spaces (e.g. produced by an illegal addrspacecast). Such pointers have no
+// register class or load/store selection pattern.
+static bool isUnsupportedPointerType(LLT Ty) {
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arsenm wrote:

Unrecognized address spaces are supposed to be treated as aliases of global

https://github.com/llvm/llvm-project/pull/200099