diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -73,7 +73,14 @@
 
 - Support has been added for the following processors (``-mcpu`` identifiers in parentheses):
 
+  - RISC-V SiFive E20 (``sifive-e20``).
+  - RISC-V SiFive E21 (``sifive-e21``).
+  - RISC-V SiFive E24 (``sifive-e24``).
+  - RISC-V SiFive E34 (``sifive-e34``).
+  - RISC-V SiFive S21 (``sifive-s21``).
   - RISC-V SiFive S51 (``sifive-s51``).
+  - RISC-V SiFive S54 (``sifive-s54``).
+  - RISC-V SiFive S76 (``sifive-s76``).
 
 Removed Compiler Flags
 -------------------------
diff --git a/clang/test/Driver/riscv-cpus.c b/clang/test/Driver/riscv-cpus.c
--- a/clang/test/Driver/riscv-cpus.c
+++ b/clang/test/Driver/riscv-cpus.c
@@ -45,6 +45,39 @@
 // RUN: %clang -target riscv64 -### -c %s 2>&1 -mtune=sifive-7-series | FileCheck -check-prefix=MTUNE-SIFIVE7-SERIES-64 %s
 // MTUNE-SIFIVE7-SERIES-64: "-tune-cpu" "sifive-7-rv64"
 
+// mcpu with default march
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-e20 | FileCheck -check-prefix=MCPU-SIFIVE-E20 %s
+// MCPU-SIFIVE-E20: "-nostdsysteminc" "-target-cpu" "sifive-e20"
+// MCPU-SIFIVE-E20: "-target-feature" "+m" "-target-feature" "+c"
+// MCPU-SIFIVE-E20: "-target-abi" "ilp32"
+
+// mcpu with default march
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-e21 | FileCheck -check-prefix=MCPU-SIFIVE-E21 %s
+// MCPU-SIFIVE-E21: "-nostdsysteminc" "-target-cpu" "sifive-e21"
+// MCPU-SIFIVE-E21: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+c"
+// MCPU-SIFIVE-E21: "-target-abi" "ilp32"
+
+// mcpu with default march
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-e24 | FileCheck -check-prefix=MCPU-SIFIVE-E24 %s
+// MCPU-SIFIVE-E24: "-nostdsysteminc" "-target-cpu" "sifive-e24"
+// MCPU-SIFIVE-E24: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f"
+// MCPU-SIFIVE-E24: "-target-feature" "+c"
+// MCPU-SIFIVE-E24: "-target-abi" "ilp32"
+
+// mcpu with default march
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-e34 | FileCheck -check-prefix=MCPU-SIFIVE-E34 %s
+// MCPU-SIFIVE-E34: "-nostdsysteminc" "-target-cpu" "sifive-e34"
+// MCPU-SIFIVE-E34: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f"
+// MCPU-SIFIVE-E34: "-target-feature" "+c"
+// MCPU-SIFIVE-E34: "-target-abi" "ilp32"
+
+// mcpu with mabi option
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-s21 -mabi=lp64 | FileCheck -check-prefix=MCPU-ABI-SIFIVE-S21 %s
+// MCPU-ABI-SIFIVE-S21: "-nostdsysteminc" "-target-cpu" "sifive-s21"
+// MCPU-ABI-SIFIVE-S21: "-target-feature" "+m" "-target-feature" "+a"
+// MCPU-ABI-SIFIVE-S21: "-target-feature" "+c" "-target-feature" "+64bit"
+// MCPU-ABI-SIFIVE-S21: "-target-abi" "lp64"
+
 // mcpu with mabi option
 // RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-s51 -mabi=lp64 | FileCheck -check-prefix=MCPU-ABI-SIFIVE-S51 %s
 // MCPU-ABI-SIFIVE-S51: "-nostdsysteminc" "-target-cpu" "sifive-s51"
@@ -52,6 +85,20 @@
 // MCPU-ABI-SIFIVE-S51: "-target-feature" "+c" "-target-feature" "+64bit"
 // MCPU-ABI-SIFIVE-S51: "-target-abi" "lp64"
 
+// mcpu with default march
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-s54 | FileCheck -check-prefix=MCPU-SIFIVE-S54 %s
+// MCPU-SIFIVE-S54: "-nostdsysteminc" "-target-cpu" "sifive-s54"
+// MCPU-SIFIVE-S54: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f" "-target-feature" "+d"
+// MCPU-SIFIVE-S54: "-target-feature" "+c" "-target-feature" "+64bit"
+// MCPU-SIFIVE-S54: "-target-abi" "lp64d"
+
+// mcpu with mabi option
+// RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-s76 | FileCheck -check-prefix=MCPU-SIFIVE-S76 %s
+// MCPU-SIFIVE-S76: "-nostdsysteminc" "-target-cpu" "sifive-s76"
+// MCPU-SIFIVE-S76: "-target-feature" "+m" "-target-feature" "+a" "-target-feature" "+f" "-target-feature" "+d"
+// MCPU-SIFIVE-S76: "-target-feature" "+c" "-target-feature" "+64bit"
+// MCPU-SIFIVE-S76: "-target-abi" "lp64d"
+
 // mcpu with default march
 // RUN: %clang -target riscv64 -### -c %s 2>&1 -mcpu=sifive-u54 | FileCheck -check-prefix=MCPU-SIFIVE-U54 %s
 // MCPU-SIFIVE-U54: "-nostdsysteminc" "-target-cpu" "sifive-u54"
diff --git a/clang/test/Misc/target-invalid-cpu-note.c b/clang/test/Misc/target-invalid-cpu-note.c
--- a/clang/test/Misc/target-invalid-cpu-note.c
+++ b/clang/test/Misc/target-invalid-cpu-note.c
@@ -196,16 +196,16 @@
 
 // RUN: not %clang_cc1 -triple riscv32 -target-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix RISCV32
 // RISCV32: error: unknown target CPU 'not-a-cpu'
-// RISCV32: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e31, sifive-e76
+// RISCV32: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76
 
 // RUN: not %clang_cc1 -triple riscv64 -target-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix RISCV64
 // RISCV64: error: unknown target CPU 'not-a-cpu'
-// RISCV64: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s51, sifive-u54, sifive-u74
+// RISCV64: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74
 
 // RUN: not %clang_cc1 -triple riscv32 -tune-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix TUNE-RISCV32
 // TUNE-RISCV32: error: unknown target CPU 'not-a-cpu'
-// TUNE-RISCV32: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e31, sifive-e76, generic, rocket, sifive-7-series
+// TUNE-RISCV32: note: valid target CPU values are: generic-rv32, rocket-rv32, sifive-7-rv32, sifive-e20, sifive-e21, sifive-e24, sifive-e31, sifive-e34, sifive-e76, generic, rocket, sifive-7-series
 
 // RUN: not %clang_cc1 -triple riscv64 -tune-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix TUNE-RISCV64
 // TUNE-RISCV64: error: unknown target CPU 'not-a-cpu'
-// TUNE-RISCV64: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s51, sifive-u54, sifive-u74, generic, rocket, sifive-7-series
+// TUNE-RISCV64: note: valid target CPU values are: generic-rv64, rocket-rv64, sifive-7-rv64, sifive-s21, sifive-s51, sifive-s54, sifive-s76, sifive-u54, sifive-u74, generic, rocket, sifive-7-series
diff --git a/llvm/include/llvm/Support/RISCVTargetParser.def b/llvm/include/llvm/Support/RISCVTargetParser.def
--- a/llvm/include/llvm/Support/RISCVTargetParser.def
+++ b/llvm/include/llvm/Support/RISCVTargetParser.def
@@ -19,10 +19,17 @@
 PROC(ROCKET_RV64, {"rocket-rv64"}, FK_64BIT, {""})
 PROC(SIFIVE_732, {"sifive-7-rv32"}, FK_NONE, {""})
 PROC(SIFIVE_764, {"sifive-7-rv64"}, FK_64BIT, {""})
+PROC(SIFIVE_E20, {"sifive-e20"}, FK_NONE, {"rv32imc"})
+PROC(SIFIVE_E21, {"sifive-e21"}, FK_NONE, {"rv32imac"})
+PROC(SIFIVE_E24, {"sifive-e24"}, FK_NONE, {"rv32imafc"})
 PROC(SIFIVE_E31, {"sifive-e31"}, FK_NONE, {"rv32imac"})
+PROC(SIFIVE_E34, {"sifive-e34"}, FK_NONE, {"rv32imafc"})
+PROC(SIFIVE_E76, {"sifive-e76"}, FK_NONE, {"rv32imafc"})
+PROC(SIFIVE_S21, {"sifive-s21"}, FK_64BIT, {"rv64imac"})
 PROC(SIFIVE_S51, {"sifive-s51"}, FK_64BIT, {"rv64imac"})
+PROC(SIFIVE_S54, {"sifive-s54"}, FK_64BIT, {"rv64gc"})
+PROC(SIFIVE_S76, {"sifive-s76"}, FK_64BIT, {"rv64gc"})
 PROC(SIFIVE_U54, {"sifive-u54"}, FK_64BIT, {"rv64gc"})
-PROC(SIFIVE_E76, {"sifive-e76"}, FK_NONE, {"rv32imafc"})
 PROC(SIFIVE_U74, {"sifive-u74"}, FK_64BIT, {"rv64gc"})
 
 #undef PROC
diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -250,27 +250,63 @@
 def : ProcessorModel<"sifive-7-rv32", SiFive7Model, []>;
 def : ProcessorModel<"sifive-7-rv64", SiFive7Model, [Feature64Bit]>;
 
+def : ProcessorModel<"sifive-e20", RocketModel, [FeatureStdExtM,
+                                                 FeatureStdExtC]>;
+
+def : ProcessorModel<"sifive-e21", RocketModel, [FeatureStdExtM,
+                                                 FeatureStdExtA,
+                                                 FeatureStdExtC]>;
+
+def : ProcessorModel<"sifive-e24", RocketModel, [FeatureStdExtM,
+                                                 FeatureStdExtA,
+                                                 FeatureStdExtF,
+                                                 FeatureStdExtC]>;
+
 def : ProcessorModel<"sifive-e31", RocketModel, [FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtC]>;
 
+def : ProcessorModel<"sifive-e34", RocketModel, [FeatureStdExtM,
+                                                 FeatureStdExtA,
+                                                 FeatureStdExtF,
+                                                 FeatureStdExtC]>;
+
+def : ProcessorModel<"sifive-e76", SiFive7Model, [FeatureStdExtM,
+                                                  FeatureStdExtA,
+                                                  FeatureStdExtF,
+                                                  FeatureStdExtC]>;
+
+def : ProcessorModel<"sifive-s21", RocketModel, [Feature64Bit,
+                                                 FeatureStdExtM,
+                                                 FeatureStdExtA,
+                                                 FeatureStdExtC]>;
+
 def : ProcessorModel<"sifive-s51", RocketModel, [Feature64Bit,
                                                  FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-u54", RocketModel, [Feature64Bit,
+def : ProcessorModel<"sifive-s54", RocketModel, [Feature64Bit,
                                                  FeatureStdExtM,
                                                  FeatureStdExtA,
                                                  FeatureStdExtF,
                                                  FeatureStdExtD,
                                                  FeatureStdExtC]>;
 
-def : ProcessorModel<"sifive-e76", SiFive7Model, [FeatureStdExtM,
+def : ProcessorModel<"sifive-s76", SiFive7Model, [Feature64Bit,
+                                                  FeatureStdExtM,
                                                   FeatureStdExtA,
                                                   FeatureStdExtF,
+                                                  FeatureStdExtD,
                                                   FeatureStdExtC]>;
 
+def : ProcessorModel<"sifive-u54", RocketModel, [Feature64Bit,
+                                                 FeatureStdExtM,
+                                                 FeatureStdExtA,
+                                                 FeatureStdExtF,
+                                                 FeatureStdExtD,
+                                                 FeatureStdExtC]>;
+
 def : ProcessorModel<"sifive-u74", SiFive7Model, [Feature64Bit,
                                                   FeatureStdExtM,
                                                   FeatureStdExtA,