diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -71,6 +71,18 @@
   return Ext.consume_front("experimental-");
 }
 
+static size_t findFirstNonVersionCharacter(const StringRef &Ext) {
+  int Pos = Ext.size() - 1;
+  while (Pos >= 0 && isDigit(Ext[Pos]))
+    Pos--;
+  if (Pos > 0 && Ext[Pos] == 'p' && isDigit(Ext[Pos - 1])) {
+    Pos--;
+    while (Pos >= 0 && isDigit(Ext[Pos]))
+      Pos--;
+  }
+  return Pos;
+}
+
 struct FindByName {
   FindByName(StringRef Ext) : Ext(Ext){};
   StringRef Ext;
@@ -637,7 +649,7 @@
 
     StringRef Type = getExtensionType(Ext);
     StringRef Desc = getExtensionTypeDesc(Ext);
-    auto Pos = Ext.find_if(isDigit);
+    auto Pos = findFirstNonVersionCharacter(Ext) + 1;
     StringRef Name(Ext.substr(0, Pos));
     StringRef Vers(Ext.substr(Pos));