diff --git a/llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/X86/BUILD.gn b/llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/X86/BUILD.gn
index 42bce295c9a7e..c93827d8cbd7d 100644
--- a/llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/X86/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/X86/BUILD.gn
@@ -14,6 +14,9 @@ static_library("X86") {
     # depend on this Target/X86-internal build target.
     "//llvm/lib/Target/X86/MCTargetDesc",
   ]
-  sources = [ "Target.cpp" ]
+  sources = [
+    # Make `gn format` not collapse this, for sync_source_lists_from_cmake.py.
+    "Target.cpp",
+  ]
   include_dirs = [ "//llvm/lib/Target/X86" ]
 }