diff --git a/utils/vim/llvm.vim b/utils/vim/llvm.vim
index 2d8847c945b..a51e5e623c8 100644
--- a/utils/vim/llvm.vim
+++ b/utils/vim/llvm.vim
@@ -51,7 +51,7 @@ syn keyword llvmKeyword x86_stdcallcc x86_fastcallcc
 syn keyword llvmKeyword signext zeroext inreg sret nounwind noreturn
 syn keyword llvmKeyword nocapture byval nest readnone readonly noalias
 syn keyword llvmKeyword inlinehint noinline alwaysinline optsize ssp sspreq
-syn keyword llvmKeyword noredzone noimplicitfloat naked
+syn keyword llvmKeyword noredzone noimplicitfloat naked alignstack
 syn keyword llvmKeyword module asm align tail to
 syn keyword llvmKeyword addrspace section alias sideeffect c gc
 syn keyword llvmKeyword target datalayout triple