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

[Matt Arsenault via llvm-commits]

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@@ -616,6 +618,21 @@ else ()
   endif ()
 endif ()
 
+foreach(i IN ITEMS 8 4)
+  try_compile(SIZEOF_UINTPTR_T_IS_${i}
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arsenm wrote:

Which is correct? The point is to match what the compiler is being compiled for 

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