[clang] [llvm] [ARM] Emit an error when the hard-float ABI is enabled but can't be used (PR #111334)

[Peter Smith via cfe-commits]

================
@@ -1690,7 +1690,7 @@ ARMTargetLowering::getEffectiveCallingConv(CallingConv::ID CC,
                                            bool isVarArg) const {
   switch (CC) {
   default:
-    report_fatal_error("Unsupported calling convention");
+    // Unknown CCs are rejected when calling convention lowering is required.
----------------
smithp35 wrote:

Not a comment on the patch. Just in case other reviews look. The check is in CCAssignFnForNode which isn't covered touched by this diff.

https://github.com/llvm/llvm-project/pull/111334