diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1802,10 +1802,15 @@
       }
       Lex.Lex();
       return false;
-    } else if (Lex.getKind() != lltok::APSInt) {
-      return tokError("expected integer or string constant");
     }
-    return parseUInt32(AddrSpace);
+    if (Lex.getKind() != lltok::APSInt)
+      return tokError("expected integer or string constant");
+    SMLoc Loc = Lex.getLoc();
+    if (parseUInt32(AddrSpace))
+      return true;
+    if (!isUInt<24>(AddrSpace))
+      return error(Loc, "invalid address space, must be a 24-bit integer");
+    return false;
   };
 
   return parseToken(lltok::lparen, "expected '(' in address space") ||
diff --git a/llvm/test/Assembler/invalid-addrspace.ll b/llvm/test/Assembler/invalid-addrspace.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Assembler/invalid-addrspace.ll
@@ -0,0 +1,8 @@
+; RUN: not llvm-as < %s 2>&1 | FileCheck %s
+; Check that parser rejects address spaces that are too large to fit in the 24 bits
+
+define void @f() {
+; CHECK: invalid address space, must be a 24-bit integer
+  %y = alloca i32, addrspace(16777216)
+  ret void
+}