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
@@ -15,6 +15,7 @@
 #include "llvm/Support/raw_ostream.h"
 
 #include <array>
+#include <iostream>
 #include <string>
 #include <vector>
 
@@ -64,6 +65,7 @@
 
     {"zvamo", RISCVExtensionVersion{0, 10}},
     {"zvlsseg", RISCVExtensionVersion{0, 10}},
+    {"zvl128b", RISCVExtensionVersion{0, 10}},
 
     {"zfh", RISCVExtensionVersion{0, 1}},
 };
@@ -72,6 +74,18 @@
   return Ext.consume_front("experimental-");
 }
 
+static size_t findFirstNonVersionCharacter(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;
+}
+
 void RISCVISAInfo::addExtension(StringRef ExtName, unsigned MajorVersion,
                                 unsigned MinorVersion) {
   RISCVExtensionInfo Ext;
@@ -612,7 +626,7 @@
 
     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));