[MLIR] Remove LLVM typed pointer support

This breaks lowering to typed pointers, and forces import to always
use opaque pointers.

This has no effect on MLIR-level typed pointer support in the
LLVMIR dialect.

Author: nikic

mlir/lib/Target/LLVMIR/TypeFromLLVM.cpp

@@ -97,12 +97,7 @@ class TypeFromLLVMIRTranslatorImpl {
 
   /// Translates the given pointer type.
   Type translate(llvm::PointerType *type) {
-    if (type->isOpaque())
-      return LLVM::LLVMPointerType::get(&context, type->getAddressSpace());
-
-    return LLVM::LLVMPointerType::get(
-        translateType(type->getNonOpaquePointerElementType()),
-        type->getAddressSpace());
+    return LLVM::LLVMPointerType::get(&context, type->getAddressSpace());
   }
 
   /// Translates the given structure type.

mlir/lib/Target/LLVMIR/TypeToLLVM.cpp

@@ -106,10 +106,7 @@ class TypeToLLVMIRTranslatorImpl {
 
   /// Translates the given pointer type.
   llvm::Type *translate(LLVM::LLVMPointerType type) {
-    if (type.isOpaque())
-      return llvm::PointerType::get(context, type.getAddressSpace());
-    return llvm::PointerType::get(translateType(type.getElementType()),
-                                  type.getAddressSpace());
+    return llvm::PointerType::get(context, type.getAddressSpace());
   }
 
   /// Translates the given structure type, supports both identified and literal