diff --git a/clang/test/Driver/riscv-cpus.c b/clang/test/Driver/riscv-cpus.c
index d181755bb5850..015df83e77800 100644
--- a/clang/test/Driver/riscv-cpus.c
+++ b/clang/test/Driver/riscv-cpus.c
@@ -228,14 +228,20 @@
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+f"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+d"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+c"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+zic64b"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zicbom"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zicbop"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zicboz"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+ziccamoa"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+ziccif"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+zicclsm"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+ziccrse"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zicsr"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zifencei"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zihintntl"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zihintpause"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zihpm"
+// MCPU-SIFIVE-P450-SAME: "-target-feature" "+za64rs"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zfhmin"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zba"
 // MCPU-SIFIVE-P450-SAME: "-target-feature" "+zbb"
diff --git a/llvm/lib/Target/RISCV/RISCVProcessors.td b/llvm/lib/Target/RISCV/RISCVProcessors.td
index d1cd9ba1dd84d..c8cf3644b21fb 100644
--- a/llvm/lib/Target/RISCV/RISCVProcessors.td
+++ b/llvm/lib/Target/RISCV/RISCVProcessors.td
@@ -223,9 +223,15 @@ def SIFIVE_P450 : RISCVProcessorModel<"sifive-p450", SiFiveP400Model,
                                        FeatureStdExtF,
                                        FeatureStdExtD,
                                        FeatureStdExtC,
+                                       FeatureStdExtZa64rs,
+                                       FeatureStdExtZic64b,
                                        FeatureStdExtZicbop,
                                        FeatureStdExtZicbom,
                                        FeatureStdExtZicboz,
+                                       FeatureStdExtZiccamoa,
+                                       FeatureStdExtZiccif,
+                                       FeatureStdExtZicclsm,
+                                       FeatureStdExtZiccrse,
                                        FeatureStdExtZihintntl,
                                        FeatureStdExtZihintpause,
                                        FeatureStdExtZihpm,