diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 2d787b6a9a94..c89e738a8b9b 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1745,7 +1745,10 @@ bool X86AsmParser::ParseDirective(AsmToken DirectiveID) {
     return ParseDirectiveWord(2, DirectiveID.getLoc());
   else if (IDVal.startswith(".code"))
     return ParseDirectiveCode(IDVal, DirectiveID.getLoc());
-  else if (IDVal.startswith(".intel_syntax")) {
+  else if (IDVal.startswith(".att_syntax")) {
+    getParser().setAssemblerDialect(0);
+    return false;
+  } else if (IDVal.startswith(".intel_syntax")) {
     getParser().setAssemblerDialect(1);
     if (getLexer().isNot(AsmToken::EndOfStatement)) {
       if(Parser.getTok().getString() == "noprefix") {
diff --git a/llvm/test/MC/X86/intel-syntax-2.s b/llvm/test/MC/X86/intel-syntax-2.s
index ca4afc317398..c377e1a57e91 100644
--- a/llvm/test/MC/X86/intel-syntax-2.s
+++ b/llvm/test/MC/X86/intel-syntax-2.s
@@ -1,7 +1,9 @@
-// RUN: llvm-mc -triple x86_64-unknown-unknown  %s | FileCheck %s
+// RUN: llvm-mc -triple x86_64-unknown-unknown -x86-asm-syntax=att %s | FileCheck %s
 
 	.intel_syntax
 _test:
 // CHECK:	movl	$257, -4(%rsp)
 	mov	DWORD PTR [RSP - 4], 257
-
+    .att_syntax
+// CHECK:	movl	$257, -4(%rsp)
+    movl $257, -4(%rsp)
\ No newline at end of file