diff --git a/compiler-rt/lib/Makefile.mk b/compiler-rt/lib/Makefile.mk
index 3068485c010e..8b912c43cf30 100644
--- a/compiler-rt/lib/Makefile.mk
+++ b/compiler-rt/lib/Makefile.mk
@@ -22,13 +22,8 @@ SubDirs += tsan
 SubDirs += msan
 SubDirs += ubsan
 
-# FIXME: We don't currently support building an atomic library, and as it must
-# be a separate library from the runtime library, we need to remove its source
-# code from the source files list.
-ExcludedSources := atomic.c
-
 # Define the variables for this specific directory.
-Sources := $(foreach file,$(wildcard $(Dir)/*.c),$(filter-out $(ExcludedSources),$(notdir $(file))))
+Sources := $(foreach file,$(wildcard $(Dir)/*.c),$(notdir $(file)))
 ObjNames := $(Sources:%.c=%.o)
 Implementation := Generic