Index: llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
===================================================================
--- llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -244,10 +244,11 @@
 
     // Alias .hword/.word/xword to the target-independent .2byte/.4byte/.8byte
     // directives as they have the same form and semantics:
-    ///  ::= (.hword | .word | .xword ) [ expression (, expression)* ]
+    ///  ::= (.hword | .word | .xword | .dword ) [ expression (, expression)* ]
     Parser.addAliasForDirective(".hword", ".2byte");
     Parser.addAliasForDirective(".word", ".4byte");
     Parser.addAliasForDirective(".xword", ".8byte");
+    Parser.addAliasForDirective(".dword", ".8byte");
 
     // Initialize the set of available features.
     setAvailableFeatures(ComputeAvailableFeatures(getSTI().getFeatureBits()));
Index: llvm/test/MC/AArch64/data-directives-invalid.s
===================================================================
--- /dev/null
+++ llvm/test/MC/AArch64/data-directives-invalid.s
@@ -0,0 +1,16 @@
+# RUN: not llvm-mc -triple aarch64 < %s 2>&1 | FileCheck %s
+
+# CHECK: [[@LINE+1]]:8: error: out of range literal value in '.hword' directive
+.hword 0xffffa
+# CHECK: [[@LINE+1]]:8: error: out of range literal value in '.2byte' directive
+.2byte 0xffffa
+# CHECK: [[@LINE+1]]:7: error: out of range literal value in '.word' directive
+.word 0xffffffffa
+# CHECK: [[@LINE+1]]:8: error: out of range literal value in '.4byte' directive
+.4byte 0xffffffffa
+# CHECK: [[@LINE+1]]:8: error: literal value out of range for directive in '.dword' directive
+.dword 0xffffffffffffffffa
+# CHECK: [[@LINE+1]]:8: error: literal value out of range for directive in '.xword' directive
+.xword 0xffffffffffffffffa
+# CHECK: [[@LINE+1]]:8: error: literal value out of range for directive in '.8byte' directive
+.8byte 0xffffffffffffffffa