Index: llvm/include/llvm/IR/Type.h
===================================================================
--- llvm/include/llvm/IR/Type.h
+++ llvm/include/llvm/IR/Type.h
@@ -227,6 +227,9 @@
   /// True if this is an instance of PointerType.
   bool isPointerTy() const { return getTypeID() == PointerTyID; }
 
+  /// True if this is an instance of PointerType that's opaque.
+  bool isOpaquePointerTy() const { return isPointerTy() && !NumContainedTys; }
+
   /// Return true if this is a pointer type or a vector of pointer types.
   bool isPtrOrPtrVectorTy() const { return getScalarType()->isPointerTy(); }
 
Index: llvm/lib/AsmParser/LLParser.cpp
===================================================================
--- llvm/lib/AsmParser/LLParser.cpp
+++ llvm/lib/AsmParser/LLParser.cpp
@@ -2597,6 +2597,8 @@
         return tokError("basic block pointers are invalid");
       if (Result->isVoidTy())
         return tokError("pointers to void are invalid - use i8* instead");
+      if (Result->isOpaquePointerTy())
+        return tokError("ptr* is invalid - use ptr instead");
       if (!PointerType::isValidElementType(Result))
         return tokError("pointer to this type is invalid");
       Result = PointerType::getUnqual(Result);
Index: llvm/test/Assembler/invalid-opaque-ptr-addrspace.ll
===================================================================
--- /dev/null
+++ llvm/test/Assembler/invalid-opaque-ptr-addrspace.ll
@@ -0,0 +1,7 @@
+; RUN: not llvm-as < %s -disable-output 2>&1 | FileCheck %s
+
+; CHECK: ptr* is invalid - use ptr instead
+define void @f(ptr addrspace(3) %a) {
+    %b = bitcast ptr addrspace(3) %a to ptr addrspace(3)*
+    ret void
+}
Index: llvm/test/Assembler/invalid-opaque-ptr.ll
===================================================================
--- /dev/null
+++ llvm/test/Assembler/invalid-opaque-ptr.ll
@@ -0,0 +1,7 @@
+; RUN: not llvm-as < %s -disable-output 2>&1 | FileCheck %s
+
+; CHECK: ptr* is invalid - use ptr instead
+define void @f(ptr %a) {
+    %b = bitcast ptr %a to ptr*
+    ret void
+}