[llvm] [TableGen] Use std::string::find (NFC) (PR #139681)

[Kazu Hirata via llvm-commits]

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@@ -1796,11 +1796,11 @@ const Init *TernOpInit::Fold(const Record *CurRec) const {
     if (LHSs && MHSs && RHSs) {
       std::string Val = RHSs->getValue().str();
 
-      StringRef::size_type found;
-      StringRef::size_type idx = 0;
+      std::string::size_type found;
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kazutakahirata wrote:

Good points!  Fixed in the latest revision.  Thanks!

https://github.com/llvm/llvm-project/pull/139681