Allow TargetLowering::getRegClassFor() to be called on illegal types. Also

allow target to override it in order to map register classes to illegal
but synthesizable types. e.g. v4i64, v8i64 for ARM / NEON.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103854 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMISelLowering.h

@@ -240,6 +240,10 @@ namespace llvm {
       return Subtarget;
     }
 
+    /// getRegClassFor - Return the register class that should be used for the
+    /// specified value type.
+    virtual TargetRegisterClass *getRegClassFor(EVT VT) const;
+
     /// getFunctionAlignment - Return the Log2 alignment of this function.
     virtual unsigned getFunctionAlignment(const Function *F) const;