diff --git a/mlir/include/mlir/IR/OperationSupport.h b/mlir/include/mlir/IR/OperationSupport.h
--- a/mlir/include/mlir/IR/OperationSupport.h
+++ b/mlir/include/mlir/IR/OperationSupport.h
@@ -257,6 +257,12 @@
   void set(Identifier name, Attribute value);
   void set(StringRef name, Attribute value);
 
+  /// Erase the attribute with the given name from the list. Return the
+  /// attribute that was erase, or nullptr if there was no attribute with such
+  /// name.
+  Attribute erase(Identifier name);
+  Attribute erase(StringRef name);
+
   const_iterator begin() const { return attrs.begin(); }
   const_iterator end() const { return attrs.end(); }
 
@@ -268,6 +274,9 @@
   /// Return whether the attributes are sorted.
   bool isSorted() const { return dictionarySorted.getInt(); }
 
+  /// Erase the attribute at the given iterator position.
+  Attribute eraseImpl(SmallVectorImpl<NamedAttribute>::iterator it);
+
   // These are marked mutable as they may be modified (e.g., sorted)
   mutable SmallVector<NamedAttribute, 4> attrs;
   // Pair with cached DictionaryAttr and status of whether attrs is sorted.
diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -143,6 +143,17 @@
       parser.getCurrentLocation(&trailingTypeLoc) || parser.parseType(type))
     return failure();
 
+  Optional<NamedAttribute> alignmentAttr =
+      result.attributes.getNamed("alignment");
+  if (alignmentAttr.hasValue()) {
+    auto alignmentInt = alignmentAttr.getValue().second.dyn_cast<IntegerAttr>();
+    if (!alignmentInt)
+      return parser.emitError(parser.getNameLoc(),
+                              "expected integer alignemnt");
+    if (alignmentInt.getValue().isNullValue())
+      result.attributes.erase("alignment");
+  }
+
   // Extract the result type from the trailing function type.
   auto funcType = type.dyn_cast<FunctionType>();
   if (!funcType || funcType.getNumInputs() != 1 ||
diff --git a/mlir/lib/IR/OperationSupport.cpp b/mlir/lib/IR/OperationSupport.cpp
--- a/mlir/lib/IR/OperationSupport.cpp
+++ b/mlir/lib/IR/OperationSupport.cpp
@@ -150,6 +150,26 @@
   return set(mlir::Identifier::get(name, value.getContext()), value);
 }
 
+Attribute
+NamedAttrList::eraseImpl(SmallVectorImpl<NamedAttribute>::iterator it) {
+  if (it == attrs.end())
+    return nullptr;
+
+  // Erasing does not affect the sorted property.
+  Attribute attr = it->second;
+  attrs.erase(it);
+  dictionarySorted.setPointer(nullptr);
+  return attr;
+}
+
+Attribute NamedAttrList::erase(Identifier name) {
+  return eraseImpl(findAttr(attrs, name, isSorted()));
+}
+
+Attribute NamedAttrList::erase(StringRef name) {
+  return eraseImpl(findAttr(attrs, name, isSorted()));
+}
+
 NamedAttrList &
 NamedAttrList::operator=(const SmallVectorImpl<NamedAttribute> &rhs) {
   assign(rhs.begin(), rhs.end());