[llvm-c] Remove pointee support from LLVMGetElementType

llvm/docs/ReleaseNotes.rst

 --------------------
 
 * ``LLVMContextSetOpaquePointers``, a temporary API to pin to legacy typed
   pointer, has been removed.
 * Functions for adding legacy passes like ``LLVMAddInstructionCombiningPass``
   have been removed.
 * Removed ``LLVMPassManagerBuilderRef`` and functions interacting with it.
   These belonged to the no longer supported legacy pass manager.
+* As part of the opaque pointer transition, ``LLVMGetElementType`` no longer
+  gives the pointee type of a pointer type.
 
 Changes to the FastISel infrastructure
 --------------------------------------
 
 * ...
 
 Changes to the DAG infrastructure
 ---------------------------------

llvm/include/llvm-c/Core.h

  * for array, vector, and pointer types.
  *
  * @{
  */
 
 /**
  * Obtain the element type of an array or vector type.
  *
- * This currently also works for pointer types, but this usage is deprecated.
- *
  * @see llvm::SequentialType::getElementType()
  */
 LLVMTypeRef LLVMGetElementType(LLVMTypeRef Ty);
 
 /**
  * Returns type's subtypes
  *
  * @see llvm::Type::subtypes()

llvm/lib/IR/Core.cpp

 
 LLVMTypeRef LLVMScalableVectorType(LLVMTypeRef ElementType,
                                    unsigned ElementCount) {
   return wrap(ScalableVectorType::get(unwrap(ElementType), ElementCount));
 }
 
 LLVMTypeRef LLVMGetElementType(LLVMTypeRef WrappedTy) {
   auto *Ty = unwrap(WrappedTy);
-  if (auto *PTy = dyn_cast<PointerType>(Ty))
-    return wrap(PTy->getNonOpaquePointerElementType());
   if (auto *ATy = dyn_cast<ArrayType>(Ty))
     return wrap(ATy->getElementType());
   return wrap(cast<VectorType>(Ty)->getElementType());
 }
 
 unsigned LLVMGetNumContainedTypes(LLVMTypeRef Tp) {
     return unwrap(Tp)->getNumContainedTypes();
 }