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
@@ -181,7 +181,7 @@
 // NOTE: This function is NOT able to take empty strings or strings that only
 // have version numbers and no extension name. It assumes the extension name
 // will be at least more than one character.
-static size_t findFirstNonVersionCharacter(StringRef Ext) {
+static size_t findLastNonVersionCharacter(StringRef Ext) {
   assert(!Ext.empty() &&
          "Already guarded by if-statement in ::parseArchString");
 
@@ -789,7 +789,7 @@
 
       StringRef Type = getExtensionType(Ext);
       StringRef Desc = getExtensionTypeDesc(Ext);
-      auto Pos = findFirstNonVersionCharacter(Ext) + 1;
+      auto Pos = findLastNonVersionCharacter(Ext) + 1;
       StringRef Name(Ext.substr(0, Pos));
       StringRef Vers(Ext.substr(Pos));