diff --git a/clang/lib/Driver/ToolChains/Arch/LoongArch.cpp b/clang/lib/Driver/ToolChains/Arch/LoongArch.cpp
index 771adade93813..d365997a2a536 100644
--- a/clang/lib/Driver/ToolChains/Arch/LoongArch.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/LoongArch.cpp
@@ -134,6 +134,12 @@ void loongarch::getLoongArchTargetFeatures(const Driver &D,
       (!Args.hasArgNoClaim(clang::driver::options::OPT_march_EQ)))
     Features.push_back("+lsx");
 
+  if (Args.hasFlag(options::OPT_mrelax, options::OPT_mno_relax, true)) {
+    Features.push_back("+relax");
+  } else {
+    Features.push_back("-relax");
+  }
+
   std::string ArchName;
   if (const Arg *A = Args.getLastArg(options::OPT_march_EQ))
     ArchName = A->getValue();
diff --git a/clang/test/Driver/loongarch-features.c b/clang/test/Driver/loongarch-features.c
index 90634bbcf0035..f68c1da3b4002 100644
--- a/clang/test/Driver/loongarch-features.c
+++ b/clang/test/Driver/loongarch-features.c
@@ -1,8 +1,8 @@
 // RUN: %clang --target=loongarch32 -S -emit-llvm %s -o - | FileCheck %s --check-prefix=LA32
 // RUN: %clang --target=loongarch64 -S -emit-llvm %s -o - | FileCheck %s --check-prefix=LA64
 
-// LA32: "target-features"="+32bit"
-// LA64: "target-features"="+64bit,+d,+f,+lsx,+ual"
+// LA32: "target-features"="+32bit,+relax"
+// LA64: "target-features"="+64bit,+d,+f,+lsx,+relax,+ual"
 
 int foo(void) {
   return 3;
diff --git a/clang/test/Driver/loongarch-march.c b/clang/test/Driver/loongarch-march.c
index 2d5b315d962a1..21d253da042ff 100644
--- a/clang/test/Driver/loongarch-march.c
+++ b/clang/test/Driver/loongarch-march.c
@@ -21,39 +21,39 @@
 
 // CC1-LOONGARCH64: "-target-cpu" "loongarch64"
 // CC1-LOONGARCH64-NOT: "-target-feature"
-// CC1-LOONGARCH64: "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+ual"
+// CC1-LOONGARCH64: "-target-feature" "+relax" "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+ual"
 // CC1-LOONGARCH64-NOT: "-target-feature"
 // CC1-LOONGARCH64: "-target-abi" "lp64d"
 
 // CC1-LA464: "-target-cpu" "la464"
 // CC1-LA464-NOT: "-target-feature"
-// CC1-LA464: "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual"
+// CC1-LA464: "-target-feature" "+relax" "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual"
 // CC1-LA464-NOT: "-target-feature"
 // CC1-LA464: "-target-abi" "lp64d"
 
 // CC1-LA64V1P0: "-target-cpu" "loongarch64"
 // CC1-LA64V1P0-NOT: "-target-feature"
-// CC1-LA64V1P0: "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual"
+// CC1-LA64V1P0: "-target-feature" "+relax" "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual"
 // CC1-LA64V1P0-NOT: "-target-feature"
 // CC1-LA64V1P0: "-target-abi" "lp64d"
 
 // CC1-LA64V1P1: "-target-cpu" "loongarch64"
 // CC1-LA64V1P1-NOT: "-target-feature"
-// CC1-LA64V1P1: "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual" "-target-feature" "+frecipe"
+// CC1-LA64V1P1: "-target-feature" "+relax" "-target-feature" "+64bit" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+ual" "-target-feature" "+frecipe"
 // CC1-LA64V1P1-NOT: "-target-feature"
 // CC1-LA64V1P1: "-target-abi" "lp64d"
 
 // CC1-LA664: "-target-cpu" "la664"
 // CC1-LA664-NOT: "-target-feature"
-// CC1-LA664: "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual" "-target-feature" "+frecipe"
+// CC1-LA664: "-target-feature" "+relax" "-target-feature" "+64bit" "-target-feature" "+f" "-target-feature" "+d" "-target-feature" "+lsx" "-target-feature" "+lasx" "-target-feature" "+ual" "-target-feature" "+frecipe"
 // CC1-LA664-NOT: "-target-feature"
 // CC1-LA664: "-target-abi" "lp64d"
 
-// IR-LOONGARCH64: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+f,+ual"
-// IR-LA464: attributes #[[#]] ={{.*}}"target-cpu"="la464" {{.*}}"target-features"="+64bit,+d,+f,+lasx,+lsx,+ual"
-// IR-LA64V1P0: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+lsx,+ual"
-// IR-LA64V1P1: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+frecipe,+lsx,+ual"
-// IR-LA664: attributes #[[#]] ={{.*}}"target-cpu"="la664" {{.*}}"target-features"="+64bit,+d,+f,+frecipe,+lasx,+lsx,+ual"
+// IR-LOONGARCH64: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+f,+relax,+ual"
+// IR-LA464: attributes #[[#]] ={{.*}}"target-cpu"="la464" {{.*}}"target-features"="+64bit,+d,+f,+lasx,+lsx,+relax,+ual"
+// IR-LA64V1P0: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+lsx,+relax,+ual"
+// IR-LA64V1P1: attributes #[[#]] ={{.*}}"target-cpu"="loongarch64" {{.*}}"target-features"="+64bit,+d,+frecipe,+lsx,+relax,+ual"
+// IR-LA664: attributes #[[#]] ={{.*}}"target-cpu"="la664" {{.*}}"target-features"="+64bit,+d,+f,+frecipe,+lasx,+lsx,+relax,+ual"
 
 int foo(void) {
   return 3;