[COFF, ARM64] Add __getReg intrinsic

Reviewers: rnk, mstorsjo, compnerd, TomTan, haripul, javed.absar, efriedma

Reviewed By: efriedma

Subscribers: peter.smith, efriedma, kristof.beyls, chrib, cfe-commits

Differential Revision: https://reviews.llvm.org/D52838

llvm-svn: 343824
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index d6183dd..1136263 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -1749,6 +1749,9 @@
       BuiltinID == AArch64::BI__builtin_arm_wsrp)
     return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true);
 
+  if (BuiltinID == AArch64::BI__getReg)
+    return SemaBuiltinConstantArgRange(TheCall, 0, 0, 31);
+
   if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
     return true;