diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -761,6 +761,8 @@
     StringRef MArchName = riscv::getRISCVArch(Args, getToolChain().getTriple());
     CmdArgs.push_back("-march");
     CmdArgs.push_back(MArchName.data());
+    if (!Args.hasFlag(options::OPT_mrelax, options::OPT_mno_relax))
+      CmdArgs.push_back("-mno-relax");
     break;
   }
   case llvm::Triple::sparc:
diff --git a/clang/test/Driver/riscv-gnutools.c b/clang/test/Driver/riscv-gnutools.c
--- a/clang/test/Driver/riscv-gnutools.c
+++ b/clang/test/Driver/riscv-gnutools.c
@@ -16,9 +16,14 @@
 // RUN: %clang -target riscv32 --gcc-toolchain=%S/Inputs/basic_riscv32_tree -fno-integrated-as %s -### -c -march=rv32g \
 // RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV32G-ILP32D %s
 
+// Check -mno-relax has passed when -fno-integrated-as specified
+// RUN: %clang -target riscv32 --gcc-toolchain=%S/Inputs/basic_riscv32_tree -mno-relax -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV32-NO-RELAX %s
+
 // CHECK-RV32IMAC-ILP32: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32" "-march" "rv32imac"
 // CHECK-RV32IMAFDC-ILP32D: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32d" "-march" "rv32imafdc"
 // CHECK-RV32G-ILP32D: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32d" "-march" "rv32g"
+// CHECK-RV32-NO-RELAX: "{{.*}}as{{(.exe)?}}" "{{.*}}" "-mno-relax"
 
 
 // 64-bit checks
@@ -35,6 +40,11 @@
 // RUN: %clang -target riscv64 --gcc-toolchain=%S/Inputs/basic_riscv64_tree -fno-integrated-as %s -### -c -march=rv64g \
 // RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV64G-LP64D %s
 
+// Check -mno-relax has passed when -fno-integrated-as specified
+// RUN: %clang -target riscv64 --gcc-toolchain=%S/Inputs/basic_riscv64_tree -mno-relax -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=CHECK-RV64-NO-RELAX %s
+
 // CHECK-RV64IMAC-LP64: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64" "-march" "rv64imac"
 // CHECK-RV64IMAFDC-LP64D: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64d" "-march" "rv64imafdc"
 // CHECK-RV64G-LP64D: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64d" "-march" "rv64g"
+// CHECK-RV64-NO-RELAX: "{{.*}}as{{(.exe)?}}" "{{.*}}" "-mno-relax"