[llvm] RuntimeLibcalls: Add bitset for available libcalls (PR #150869)

[Matt Arsenault via llvm-commits]

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@@ -401,7 +402,13 @@ void RuntimeLibcallEmitter::emitSystemRuntimeLibrarySetCalls(
     PredicateSorter.insert(
         PredicateWithCC()); // No predicate or CC override first.
 
+    constexpr unsigned BitsPerStorageElt = sizeof(uintptr_t) * CHAR_BIT;
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arsenm wrote:

I'm not sure there's a ready made way to figure out what the generated target is from here. I guess it would be easier to make the Bitset underlying type configurable to always use uint64_t 

https://github.com/llvm/llvm-project/pull/150869