diff --git a/llvm/utils/gn/secondary/llvm/lib/IR/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/IR/BUILD.gn
index b2d81b2b7134..62fa26a0cc95 100644
--- a/llvm/utils/gn/secondary/llvm/lib/IR/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/lib/IR/BUILD.gn
@@ -16,6 +16,7 @@ static_library("IR") {
   sources = [
     "AbstractCallSite.cpp",
     "AsmWriter.cpp",
+    "Assumptions.cpp",
     "Attributes.cpp",
     "AutoUpgrade.cpp",
     "BasicBlock.cpp",