Index: llvm-toolchain-9_9.0.0/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
===================================================================
--- llvm-toolchain-9_9.0.0.orig/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
+++ llvm-toolchain-9_9.0.0/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
@@ -350,6 +350,13 @@ void riscv::getRISCVTargetFeatures(const
 
     // Handle all other types of extensions.
     getExtensionFeatures(D, Args, Features, MArch, OtherExts);
+  } else {
+    // Default to imafdc aka gc
+    Features.push_back("+m");
+    Features.push_back("+a");
+    Features.push_back("+f");
+    Features.push_back("+d");
+    Features.push_back("+c");
   }
 
   // -mrelax is default, unless -mno-relax is specified.
@@ -375,5 +382,5 @@ StringRef riscv::getRISCVABI(const ArgLi
   if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
     return A->getValue();
 
-  return Triple.getArch() == llvm::Triple::riscv32 ? "ilp32" : "lp64";
+  return Triple.getArch() == llvm::Triple::riscv32 ? "ilp32" : "lp64d";
 }
Index: llvm-toolchain-9_9.0.0/clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- llvm-toolchain-9_9.0.0.orig/clang/lib/Driver/ToolChains/Clang.cpp
+++ llvm-toolchain-9_9.0.0/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1862,7 +1862,7 @@ void Clang::AddRISCVTargetArgs(const Arg
   else if (Triple.getArch() == llvm::Triple::riscv32)
     ABIName = "ilp32";
   else if (Triple.getArch() == llvm::Triple::riscv64)
-    ABIName = "lp64";
+    ABIName = "lp64d";
   else
     llvm_unreachable("Unexpected triple!");