diff --git a/library/compiler-builtins/libm/Cargo.toml b/library/compiler-builtins/libm/Cargo.toml
index d9d6680409e1..106de51dfb61 100644
--- a/library/compiler-builtins/libm/Cargo.toml
+++ b/library/compiler-builtins/libm/Cargo.toml
@@ -6,6 +6,7 @@ documentation = "https://docs.rs/libm"
 keywords = ["libm", "math"]
 license = "MIT OR Apache-2.0"
 name = "libm"
+readme = "README.md"
 repository = "https://github.com/rust-lang/libm"
 version = "0.2.1"
 edition = "2018"