Index: cfe/trunk/lib/Driver/ToolChains/Gnu.cpp
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Gnu.cpp
+++ cfe/trunk/lib/Driver/ToolChains/Gnu.cpp
@@ -629,6 +629,18 @@
       ppc::getPPCAsmModeForCPU(getCPUName(Args, getToolChain().getTriple())));
     break;
   }
+  case llvm::Triple::riscv32:
+  case llvm::Triple::riscv64: {
+    StringRef ABIName = riscv::getRISCVABI(Args, getToolChain().getTriple());
+    CmdArgs.push_back("-mabi");
+    CmdArgs.push_back(ABIName.data());
+    if (const Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
+      StringRef MArch = A->getValue();
+      CmdArgs.push_back("-march");
+      CmdArgs.push_back(MArch.data());
+    }
+    break;
+  }
   case llvm::Triple::sparc:
   case llvm::Triple::sparcel: {
     CmdArgs.push_back("-32");
Index: cfe/trunk/test/Driver/riscv-gnutools.c
===================================================================
--- cfe/trunk/test/Driver/riscv-gnutools.c
+++ cfe/trunk/test/Driver/riscv-gnutools.c
@@ -0,0 +1,19 @@
+// Check gnutools are invoked with propagated values for -mabi and -march.
+
+// RUN: %clang -target riscv32 -fno-integrated-as %s -###  -c \
+// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP32 %s
+
+// RUN: %clang -target riscv32 -fno-integrated-as -march=rv32g %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP32-MARCH-G %s
+
+// RUN: %clang -target riscv64 -fno-integrated-as %s -###  -c \
+// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP64 %s
+
+// RUN: %clang -target riscv64 -fno-integrated-as -march=rv64g %s -### -c \
+// RUN: 2>&1 | FileCheck -check-prefix=MABI-ILP64-MARCH-G %s
+
+// MABI-ILP32: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32"
+// MABI-ILP32-MARCH-G: "{{.*}}as{{(.exe)?}}" "-mabi" "ilp32" "-march" "rv32g"
+
+// MABI-ILP64: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64"
+// MABI-ILP64-MARCH-G: "{{.*}}as{{(.exe)?}}" "-mabi" "lp64" "-march" "rv64g"