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
@@ -62,6 +62,8 @@
       Ext == "zbe" || Ext == "zbf" || Ext == "zbm" || Ext == "zbp" ||
       Ext == "zbr" || Ext == "zbs" || Ext == "zbt" || Ext == "zbproposedc")
     return RISCVExtensionVersion{"0", "93"};
+  if (Ext == "p")
+    return RISCVExtensionVersion{"0", "9"};
   if (Ext == "v" || Ext == "zvamo" || Ext == "zvlsseg")
     return RISCVExtensionVersion{"1", "0"};
   if (Ext == "zfh")
@@ -427,6 +429,9 @@
       Features.push_back("+experimental-zbs");
       Features.push_back("+experimental-zbt");
       break;
+    case 'p':
+      Features.push_back("+experimental-p");
+      break;
     case 'v':
       Features.push_back("+experimental-v");
       Features.push_back("+experimental-zvamo");
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
@@ -369,6 +369,25 @@
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-EXPERIMENTAL-ZBA %s
 // RV32-EXPERIMENTAL-ZBA: "-target-feature" "+experimental-zba"
 
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ip -### %s -c 2>&1 | \
+// RUN:   FileCheck -check-prefix=RV32-EXPERIMENTAL-P-NOFLAG %s
+// RV32-EXPERIMENTAL-P-NOFLAG: error: invalid arch name 'rv32ip'
+// RV32-EXPERIMENTAL-P-NOFLAG: requires '-menable-experimental-extensions'
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ip -menable-experimental-extensions -### %s -c 2>&1 | \
+// RUN:   FileCheck -check-prefix=RV32-EXPERIMENTAL-P-NOVERS %s
+// RV32-EXPERIMENTAL-P-NOVERS: error: invalid arch name 'rv32ip'
+// RV32-EXPERIMENTAL-P-NOVERS: experimental extension requires explicit version number
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ip0p1 -menable-experimental-extensions -### %s -c 2>&1 | \
+// RUN:   FileCheck -check-prefix=RV32-EXPERIMENTAL-P-BADVERS %s
+// RV32-EXPERIMENTAL-P-BADVERS: error: invalid arch name 'rv32ip0p1'
+// RV32-EXPERIMENTAL-P-BADVERS: unsupported version number 0.1 for experimental extension
+
+// RUN: %clang -target riscv32-unknown-elf -march=rv32ip0p9 -menable-experimental-extensions -### %s -c 2>&1 | \
+// RUN:   FileCheck -check-prefix=RV32-EXPERIMENTAL-P-GOODVERS %s
+// RV32-EXPERIMENTAL-P-GOODVERS: "-target-feature" "+experimental-p"
+
 // RUN: %clang -target riscv32-unknown-elf -march=rv32iv -### %s -c 2>&1 | \
 // RUN:   FileCheck -check-prefix=RV32-EXPERIMENTAL-V-NOFLAG %s
 // RV32-EXPERIMENTAL-V-NOFLAG: error: invalid arch name 'rv32iv'