[llvm] [TableGen] Print a warning when a Processor contains duplicate Features / TuneFeatures (PR #137864)

[Min-Yih Hsu via llvm-commits]

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@@ -333,6 +333,16 @@ unsigned SubtargetEmitter::cpuNames(raw_ostream &OS) {
   return Names.size();
 }
 
+static void checkDuplicateCPUFeatures(StringRef CPUName, StringRef FeatureKind,
+                                      ConstRecVec Features) {
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mshockwave wrote:

Oops, for some reason I mistakenly thought `ConstRecVec` is a typedef to a std::vector reference. It's fixed now.

https://github.com/llvm/llvm-project/pull/137864