diff --git a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
--- a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
@@ -31,26 +31,26 @@
 } // end anonymous namespace
 
 static StringRef getExtensionTypeDesc(StringRef Ext) {
-  if (Ext.startswith("sx"))
-    return "non-standard supervisor-level extension";
   if (Ext.startswith("s"))
     return "standard supervisor-level extension";
-  if (Ext.startswith("x"))
-    return "non-standard user-level extension";
+  if (Ext.startswith("h"))
+    return "standard hypervisor-level extension";
   if (Ext.startswith("z"))
-    return "standard user-level extension";
+    return "standard machine-level extension";
+  if (Ext.startswith("x"))
+    return "non-standard extension";
   return StringRef();
 }
 
 static StringRef getExtensionType(StringRef Ext) {
-  if (Ext.startswith("sx"))
-    return "sx";
   if (Ext.startswith("s"))
     return "s";
-  if (Ext.startswith("x"))
-    return "x";
+  if (Ext.startswith("h"))
+    return "h";
   if (Ext.startswith("z"))
     return "z";
+  if (Ext.startswith("x"))
+    return "x";
   return StringRef();
 }
 
@@ -74,7 +74,7 @@
   if (isExperimentalExtension(Ext))
     return true;
 
-  // LLVM does not support "sx", "s" nor "x" extensions.
+  // LLVM does not support "s", "h" nor "x" extensions.
   return false;
 }
 
@@ -161,10 +161,10 @@
 
 // Handle other types of extensions other than the standard
 // general purpose and standard user-level extensions.
-// Parse the ISA string containing non-standard user-level
-// extensions, standard supervisor-level extensions and
-// non-standard supervisor-level extensions.
-// These extensions start with 'z', 'x', 's', 'sx' prefixes, follow a
+// Parse the ISA string containing standard supervisor-level
+// extensions, standard hypervisor-level extensions,
+// standard machine-level extensions and non-standard extensions.
+// These extensions start with 's', 'h', 'z', 'x' prefixes, follow a
 // canonical order, might have a version number (major, minor)
 // and are separated by a single underscore '_'.
 // Set the hardware features for the extensions that are supported.
@@ -176,11 +176,11 @@
     return;
 
   // Multi-letter extensions are seperated by a single underscore
-  // as described in RISC-V User-Level ISA V2.2.
+  // as described in RISC-V User-Level ISA 20191213.
   SmallVector<StringRef, 8> Split;
   Exts.split(Split, StringRef("_"));
 
-  SmallVector<StringRef, 4> Prefix{"z", "x", "s", "sx"};
+  SmallVector<StringRef, 4> Prefix{"s", "h", "z", "x"};
   auto I = Prefix.begin();
   auto E = Prefix.end();
 
@@ -330,12 +330,13 @@
   // Skip rvxxx
   StringRef Exts = MArch.substr(5);
 
-  // Remove multi-letter standard extensions, non-standard extensions and
-  // supervisor-level extensions. They have 'z', 'x', 's', 'sx' prefixes.
+  // Remove multi-letter supervisor-level extensions, hypervisor-level
+  // extensions, machine-level extensions and non-standard extensions.
+  // They have 's', 'h', 'z', 'x' prefixes.
   // Parse them at the end.
-  // Find the very first occurrence of 's', 'x' or 'z'.
+  // Find the very first occurrence of 's', 'h', 'z' or 'x'.
   StringRef OtherExts;
-  size_t Pos = Exts.find_first_of("zsx");
+  size_t Pos = Exts.find_first_of("shzx");
   if (Pos != StringRef::npos) {
     OtherExts = Exts.substr(Pos);
     Exts = Exts.substr(0, Pos);
diff --git a/clang/test/Driver/riscv-arch.c b/clang/test/Driver/riscv-arch.c
--- a/clang/test/Driver/riscv-arch.c
+++ b/clang/test/Driver/riscv-arch.c
@@ -181,31 +181,25 @@
 // RV32-STD: error: invalid arch name 'rv32imqc',
 // RV32-STD: unsupported standard user-level extension 'q'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32xabc -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X %s
-// RV32X: error: invalid arch name 'rv32xabc',
-// RV32X: first letter should be 'e', 'i' or 'g'
-
-// RUN: %clang -target riscv32-unknown-elf -march=rv32sxabc -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32SX %s
-// RV32SX: error: invalid arch name 'rv32sxabc',
-// RV32SX: first letter should be 'e', 'i' or 'g'
-
 // RUN: %clang -target riscv32-unknown-elf -march=rv32sabc -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32S %s
 // RV32S: error: invalid arch name 'rv32sabc',
 // RV32S: first letter should be 'e', 'i' or 'g'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ix -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X-NAME %s
-// RV32X-NAME: error: invalid arch name 'rv32ix',
-// RV32X-NAME: non-standard user-level extension name missing after 'x'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32habc -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32H %s
+// RV32H: error: invalid arch name 'rv32habc',
+// RV32H: first letter should be 'e', 'i' or 'g'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32isx -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32SX-NAME %s
-// RV32SX-NAME: error: invalid arch name 'rv32isx',
-// RV32SX-NAME: non-standard supervisor-level extension
-// RV32SX-NAME: name missing after 'sx'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32zabc -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32Z %s
+// RV32Z: error: invalid arch name 'rv32zabc',
+// RV32Z: first letter should be 'e', 'i' or 'g'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32xabc -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X %s
+// RV32X: error: invalid arch name 'rv32xabc',
+// RV32X: first letter should be 'e', 'i' or 'g'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32is -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32S-NAME %s
@@ -213,31 +207,53 @@
 // RV32S-NAME: standard supervisor-level extension
 // RV32S-NAME: name missing after 's'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ix_s_sx -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32ALL-NAME %s
-// RV32ALL-NAME: error: invalid arch name 'rv32ix_s_sx',
-// RV32ALL-NAME: non-standard user-level extension
-// RV32ALL-NAME: name missing after 'x'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ih -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32H-NAME %s
+// RV32H-NAME: error: invalid arch name 'rv32ih',
+// RV32H-NAME: standard hypervisor-level extension
+// RV32H-NAME: name missing after 'h'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X-UNS %s
-// RV32X-UNS: error: invalid arch name 'rv32ixabc',
-// RV32X-UNS: unsupported non-standard user-level extension 'xabc'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32iz -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32Z-NAME %s
+// RV32Z-NAME: error: invalid arch name 'rv32iz',
+// RV32Z-NAME: standard machine-level extension
+// RV32Z-NAME: name missing after 'z'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ix -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X-NAME %s
+// RV32X-NAME: error: invalid arch name 'rv32ix',
+// RV32X-NAME: non-standard extension name missing after 'x'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32is_h_z_x -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32ALL-NAME %s
+// RV32ALL-NAME: error: invalid arch name 'rv32is_h_z_x',
+// RV32ALL-NAME: standard supervisor-level extension
+// RV32ALL-NAME: name missing after 's'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32isa -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32S-UNS %s
 // RV32S-UNS: error: invalid arch name 'rv32isa',
 // RV32S-UNS: unsupported standard supervisor-level extension 'sa'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32isxabc -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32SX-UNS %s
-// RV32SX-UNS: error: invalid arch name 'rv32isxabc',
-// RV32SX-UNS: unsupported non-standard supervisor-level extension 'sxabc'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ihab -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32H-UNS %s
+// RV32H-UNS: error: invalid arch name 'rv32ihab',
+// RV32H-UNS: unsupported standard hypervisor-level extension 'hab'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_sp_sxlw -### %s \
+// RUN: %clang -target riscv32-unknown-elf -march=rv32izabc -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32Z-UNS %s
+// RV32Z-UNS: error: invalid arch name 'rv32izabc',
+// RV32Z-UNS: unsupported standard machine-level extension 'zabc'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ixabcd -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32X-UNS %s
+// RV32X-UNS: error: invalid arch name 'rv32ixabcd',
+// RV32X-UNS: unsupported non-standard extension 'xabcd'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32isabc_hp_zxlw_xno -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32ALL %s
-// RV32ALL: error: invalid arch name 'rv32ixabc_sp_sxlw',
-// RV32ALL: unsupported non-standard user-level extension 'xabc'
+// RV32ALL: error: invalid arch name 'rv32isabc_hp_zxlw_xno',
+// RV32ALL: unsupported standard supervisor-level extension 'sabc'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32i20 -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-IVER %s
@@ -264,20 +280,25 @@
 // RV32-IMINOR1: error: invalid arch name 'rv32i2p1', unsupported
 // RV32-IMINOR1: version number 2.1 for extension 'i'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ixt2p -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XMINOR-MISS %s
-// RV32-XMINOR-MISS: error: invalid arch name 'rv32ixt2p',
-// RV32-XMINOR-MISS: minor version number missing after 'p' for extension 'xt'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ist2p -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-SMINOR-MISS %s
+// RV32-SMINOR-MISS: error: invalid arch name 'rv32ist2p',
+// RV32-SMINOR-MISS: minor version number missing after 'p' for extension 'st'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32iht2p -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-HMINOR-MISS %s
+// RV32-HMINOR-MISS: error: invalid arch name 'rv32iht2p',
+// RV32-HMINOR-MISS: minor version number missing after 'p' for extension 'ht'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ist2p0 -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-SMINOR0 %s
-// RV32-SMINOR0: error: invalid arch name 'rv32ist2p0',
-// RV32-SMINOR0: unsupported version number 2.0 for extension 'st'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32izt2p0 -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-ZMINOR0 %s
+// RV32-ZMINOR0: error: invalid arch name 'rv32izt2p0',
+// RV32-ZMINOR0: unsupported version number 2.0 for extension 'zt'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32isxt2p1 -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-SXMINOR1 %s
-// RV32-SXMINOR1: error: invalid arch name 'rv32isxt2p1', unsupported
-// RV32-SXMINOR1: version number 2.1 for extension 'sxt'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ixt2p1 -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XMINOR1 %s
+// RV32-XMINOR1: error: invalid arch name 'rv32ixt2p1', unsupported
+// RV32-XMINOR1: version number 2.1 for extension 'xt'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_ -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XSEP %s
@@ -289,32 +310,38 @@
 // RV32-PREFIX: error: invalid arch name 'rv32ixabc_a',
 // RV32-PREFIX: invalid extension prefix 'a'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32isabc_xdef -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-X-ORDER %s
-// RV32-X-ORDER: error: invalid arch name 'rv32isabc_xdef',
-// RV32-X-ORDER: non-standard user-level extension not given
-// RV32-X-ORDER: in canonical order 'xdef'
-
-// RUN: %clang -target riscv32-unknown-elf -march=rv32isxabc_sdef -### %s \
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ihabc_sdef -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-S-ORDER %s
-// RV32-S-ORDER: error: invalid arch name 'rv32isxabc_sdef',
+// RV32-S-ORDER: error: invalid arch name 'rv32ihabc_sdef',
 // RV32-S-ORDER: standard supervisor-level extension not given
 // RV32-S-ORDER: in canonical order 'sdef'
 
+// RUN: %clang -target riscv32-unknown-elf -march=rv32izabc_hdef -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-H-ORDER %s
+// RV32-H-ORDER: error: invalid arch name 'rv32izabc_hdef',
+// RV32-H-ORDER: standard hypervisor-level extension not given
+// RV32-H-ORDER: in canonical order 'hdef'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_zdef -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-Z-ORDER %s
+// RV32-Z-ORDER: error: invalid arch name 'rv32ixabc_zdef',
+// RV32-Z-ORDER: standard machine-level extension not given
+// RV32-Z-ORDER: in canonical order 'zdef'
+
 // RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_xabc -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XDUP %s
 // RV32-XDUP: error: invalid arch name 'rv32ixabc_xabc',
-// RV32-XDUP: duplicated non-standard user-level extension 'xabc'
+// RV32-XDUP: duplicated non-standard extension 'xabc'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_xdef -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-X-X-INVAL %s
 // RV32-X-X-INVAL: error: invalid arch name 'rv32ixabc_xdef', unsupported
-// RV32-X-X-INVAL: non-standard user-level extension 'xabc'
+// RV32-X-X-INVAL: non-standard extension 'xabc'
 
-// RUN: %clang -target riscv32-unknown-elf -march=rv32ixabc_sdef_sxghi -### %s \
-// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-X-S-SX-INVAL %s
-// RV32-X-S-SX-INVAL: error: invalid arch name 'rv32ixabc_sdef_sxghi',
-// RV32-X-S-SX-INVAL: unsupported non-standard user-level extension 'xabc'
+// RUN: %clang -target riscv32-unknown-elf -march=rv32isabc_hdef_zghi_xjkl -### %s \
+// RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-S-H-Z-X-INVAL %s
+// RV32-S-H-Z-X-INVAL: error: invalid arch name 'rv32isabc_hdef_zghi_xjkl',
+// RV32-S-H-Z-X-INVAL: unsupported standard supervisor-level extension 'sabc'
 
 // RUN: %clang -target riscv32-unknown-elf -march=rv32i -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-TARGET %s