[llvm] [NVPTX] Unify and extend barrier{.cta} intrinsic support (PR #140615)

[Artem Belevich via llvm-commits]

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@@ -1349,6 +1349,10 @@ static bool upgradeIntrinsicFunction1(Function *F, Function *&NewFn,
       else if (Name == "clz.ll" || Name == "popc.ll" || Name == "h2f" ||
                Name == "swap.lo.hi.b64")
         Expand = true;
+      else if (Name == "barrier0" || Name == "barrier.n" ||
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Artem-B wrote:

I look at this `else if()` sequence with fixed string comparisons and can't help but wonder if most of them can be consolidated into a single `StringSwitch`. 

https://github.com/llvm/llvm-project/pull/140615