[llvm-branch-commits] [llvm] RuntimeLibcalls: Use array initializers for default values (PR #143082)

[Matt Arsenault via llvm-branch-commits]

================
@@ -103,10 +103,14 @@ struct RuntimeLibcallsInfo {
 
 private:
   /// Stores the name each libcall.
-  const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL + 1];
+  const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL + 1] = {nullptr};
+
+  static_assert(static_cast<int>(CallingConv::C) == 0,
+                "default calling conv should be encoded as 0");
 
   /// Stores the CallingConv that should be used for each libcall.
-  CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL];
+  CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL] = {
+      CallingConv::C};
----------------
arsenm wrote:

```suggestion
  CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL] = {};
```

https://github.com/llvm/llvm-project/pull/143082