diff --git a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
--- a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
+++ b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
@@ -211,8 +211,11 @@
 
   if (!Args.hasArg(options::OPT_nostdlib) &&
       !Args.hasArg(options::OPT_nodefaultlibs)) {
-    if (ToolChain.ShouldLinkCXXStdlib(Args))
-      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+    if (D.CCCIsCXX()) {
+      if (ToolChain.ShouldLinkCXXStdlib(Args))
+        ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+      CmdArgs.push_back("-lm");
+    }
     CmdArgs.push_back("--start-group");
     CmdArgs.push_back("-lc");
     CmdArgs.push_back("-lgloss");
diff --git a/clang/test/Driver/riscv32-toolchain.c b/clang/test/Driver/riscv32-toolchain.c
--- a/clang/test/Driver/riscv32-toolchain.c
+++ b/clang/test/Driver/riscv32-toolchain.c
@@ -58,7 +58,7 @@
 // CXX-RV32-BAREMETAL-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1{{/|\\\\}}crtbegin.o"
 // CXX-RV32-BAREMETAL-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1"
 // CXX-RV32-BAREMETAL-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/riscv32-unknown-elf/lib"
-// CXX-RV32-BAREMETAL-ILP32: "-lstdc++" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
+// CXX-RV32-BAREMETAL-ILP32: "-lstdc++" "-lm" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
 // CXX-RV32-BAREMETAL-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1{{/|\\\\}}crtend.o"
 
 // RUN: %clangxx -### %s -fuse-ld= \
@@ -73,7 +73,7 @@
 // CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1{{/|\\\\}}crtbegin.o"
 // CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1"
 // CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-L{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1/../../..{{/|\\\\}}..{{/|\\\\}}riscv32-unknown-elf/lib"
-// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-lstdc++" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
+// CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "-lstdc++" "-lm" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
 // CXX-RV32-BAREMETAL-NOSYSROOT-ILP32: "{{.*}}/Inputs/basic_riscv32_tree/lib/gcc/riscv32-unknown-elf/8.0.1{{/|\\\\}}crtend.o"
 
 // RUN: env "PATH=" %clang -### %s -fuse-ld=ld -no-pie \
diff --git a/clang/test/Driver/riscv64-toolchain.c b/clang/test/Driver/riscv64-toolchain.c
--- a/clang/test/Driver/riscv64-toolchain.c
+++ b/clang/test/Driver/riscv64-toolchain.c
@@ -58,7 +58,7 @@
 // CXX-RV64-BAREMETAL-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1{{/|\\\\}}crtbegin.o"
 // CXX-RV64-BAREMETAL-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1"
 // CXX-RV64-BAREMETAL-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/riscv64-unknown-elf/lib"
-// CXX-RV64-BAREMETAL-LP64: "-lstdc++" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
+// CXX-RV64-BAREMETAL-LP64: "-lstdc++" "-lm" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
 // CXX-RV64-BAREMETAL-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1{{/|\\\\}}crtend.o"
 
 // RUN: env "PATH=" %clangxx -### %s -fuse-ld= \
@@ -73,7 +73,7 @@
 // CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1{{/|\\\\}}crtbegin.o"
 // CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1"
 // CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-L{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1/../../..{{/|\\\\}}..{{/|\\\\}}riscv64-unknown-elf/lib"
-// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-lstdc++" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
+// CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "-lstdc++" "-lm" "--start-group" "-lc" "-lgloss" "--end-group" "-lgcc"
 // CXX-RV64-BAREMETAL-NOSYSROOT-LP64: "{{.*}}/Inputs/basic_riscv64_tree/lib/gcc/riscv64-unknown-elf/8.0.1{{/|\\\\}}crtend.o"
 
 // RUN: env "PATH=" %clang -### %s -fuse-ld= -no-pie \