[Attributes] Remove AttrBuilder::hasAlignmentAttr() method (NFC)

This was the odd one out, with similar methods not existing for
any other attributes. In the places where it is used, it is best
replaced by AttrBuilder::getAttribute(), which allows us to both
test for presence of the attribute and retrieve its value at the
same time. (To just check for presence, contains() could be used.)

llvm/include/llvm/IR/Attributes.h

@@ -1088,9 +1088,6 @@ class AttrBuilder {
   /// Return true if the builder has IR-level attributes.
   bool hasAttributes() const { return !Attrs.empty(); }
 
-  /// Return true if the builder has an alignment attribute.
-  bool hasAlignmentAttr() const;
-
   /// Return Attribute with the given Kind. The returned attribute will be
   /// invalid if the Kind is not present in the builder.
   Attribute getAttribute(Attribute::AttrKind Kind) const;

llvm/lib/AsmParser/LLParser.cpp

@@ -172,8 +172,8 @@ bool LLParser::validateEndOfModule(bool UpgradeDebugInfo) {
 
       // If the alignment was parsed as an attribute, move to the alignment
       // field.
-      if (FnAttrs.hasAlignmentAttr()) {
-        Fn->setAlignment(FnAttrs.getAlignment());
+      if (MaybeAlign A = FnAttrs.getAlignment()) {
+        Fn->setAlignment(A);
         FnAttrs.removeAttribute(Attribute::Alignment);
       }
 
@@ -5731,8 +5731,8 @@ bool LLParser::parseFunctionHeader(Function *&Fn, bool IsDefine) {
     return error(BuiltinLoc, "'builtin' attribute not valid on function");
 
   // If the alignment was parsed as an attribute, move to the alignment field.
-  if (FuncAttrs.hasAlignmentAttr()) {
-    Alignment = FuncAttrs.getAlignment();
+  if (MaybeAlign A = FuncAttrs.getAlignment()) {
+    Alignment = A;
     FuncAttrs.removeAttribute(Attribute::Alignment);
   }
 

llvm/lib/IR/Attributes.cpp

@@ -1795,10 +1795,6 @@ bool AttrBuilder::contains(StringRef A) const {
   return getAttribute(A).isValid();
 }
 
-bool AttrBuilder::hasAlignmentAttr() const {
-  return getRawIntAttr(Attribute::Alignment) != 0;
-}
-
 bool AttrBuilder::operator==(const AttrBuilder &B) const {
   return Attrs == B.Attrs;
 }