Index: lib/CodeGen/ABIInfo.h
===================================================================
--- lib/CodeGen/ABIInfo.h
+++ lib/CodeGen/ABIInfo.h
@@ -53,12 +53,9 @@
     CodeGen::CodeGenTypes &CGT;
   protected:
     llvm::CallingConv::ID RuntimeCC;
-    llvm::CallingConv::ID BuiltinCC;
   public:
     ABIInfo(CodeGen::CodeGenTypes &cgt)
-      : CGT(cgt),
-        RuntimeCC(llvm::CallingConv::C),
-        BuiltinCC(llvm::CallingConv::C) {}
+        : CGT(cgt), RuntimeCC(llvm::CallingConv::C) {}
 
     virtual ~ABIInfo();
 
@@ -77,11 +74,6 @@
       return RuntimeCC;
     }
 
-    /// Return the calling convention to use for compiler builtins
-    llvm::CallingConv::ID getBuiltinCC() const {
-      return BuiltinCC;
-    }
-
     virtual void computeInfo(CodeGen::CGFunctionInfo &FI) const = 0;
 
     /// EmitVAArg - Emit the target dependent code to load a value of
Index: lib/CodeGen/CGExprComplex.cpp
===================================================================
--- lib/CodeGen/CGExprComplex.cpp
+++ lib/CodeGen/CGExprComplex.cpp
@@ -629,7 +629,7 @@
 
   llvm::Instruction *Call;
   RValue Res = CGF.EmitCall(FuncInfo, Callee, ReturnValueSlot(), Args, &Call);
-  cast<llvm::CallInst>(Call)->setCallingConv(CGF.CGM.getBuiltinCC());
+  cast<llvm::CallInst>(Call)->setCallingConv(CGF.CGM.getRuntimeCC());
   return Res.getComplexVal();
 }
 
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -123,7 +123,6 @@
   ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
 
   RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC();
-  BuiltinCC = getTargetCodeGenInfo().getABIInfo().getBuiltinCC();
 
   if (LangOpts.ObjC1)
     createObjCRuntime();
@@ -2646,7 +2645,7 @@
                               /*DontDefer=*/false, /*IsThunk=*/false, ExtraAttrs);
   if (auto *F = dyn_cast<llvm::Function>(C))
     if (F->empty())
-      F->setCallingConv(getBuiltinCC());
+      F->setCallingConv(getRuntimeCC());
   return C;
 }
 
Index: lib/CodeGen/CodeGenTypeCache.h
===================================================================
--- lib/CodeGen/CodeGenTypeCache.h
+++ lib/CodeGen/CodeGenTypeCache.h
@@ -112,8 +112,6 @@
 
   llvm::CallingConv::ID RuntimeCC;
   llvm::CallingConv::ID getRuntimeCC() const { return RuntimeCC; }
-  llvm::CallingConv::ID BuiltinCC;
-  llvm::CallingConv::ID getBuiltinCC() const { return BuiltinCC; }
 
   LangAS getASTAllocaAddressSpace() const { return ASTAllocaAddressSpace; }
 };
Index: lib/CodeGen/TargetInfo.cpp
===================================================================
--- lib/CodeGen/TargetInfo.cpp
+++ lib/CodeGen/TargetInfo.cpp
@@ -5690,18 +5690,6 @@
   llvm::CallingConv::ID abiCC = getABIDefaultCC();
   if (abiCC != getLLVMDefaultCC())
     RuntimeCC = abiCC;
-
-  // AAPCS apparently requires runtime support functions to be soft-float, but
-  // that's almost certainly for historic reasons (Thumb1 not supporting VFP
-  // most likely). It's more convenient for AAPCS16_VFP to be hard-float.
-
-  // The Run-time ABI for the ARM Architecture section 4.1.2 requires
-  // AEABI-complying FP helper functions to use the base AAPCS.
-  // These AEABI functions are expanded in the ARM llvm backend, all the builtin
-  // support functions emitted by clang such as the _Complex helpers follow the
-  // abiCC.
-  if (abiCC != getLLVMDefaultCC())
-      BuiltinCC = abiCC;
 }
 
 ABIArgInfo ARMABIInfo::classifyArgumentType(QualType Ty,