diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index 754b085f1a8..611dd3d1cd1 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -251,6 +251,7 @@
     ("e", Some(sym::riscv_target_feature)),
     ("f", Some(sym::riscv_target_feature)),
     ("m", Some(sym::riscv_target_feature)),
+    ("relax", Some(sym::riscv_target_feature)),
     ("v", Some(sym::riscv_target_feature)),
     ("zba", Some(sym::riscv_target_feature)),
     ("zbb", Some(sym::riscv_target_feature)),