[llvm] [TableGen] Fix concatenation of subreg and artificial subregs (PR #114391)

[Sander de Smalen via llvm-commits]

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@@ -411,6 +410,9 @@ CodeGenRegister::computeSubRegs(CodeGenRegBank &RegBank) {
         Parts.push_back(getSubRegIndex(SR->ExplicitSubRegs[j]));
     }
 
+    if (Parts.size() < 2)
+      continue;
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sdesmalen-arm wrote:

@jayfoad are you happy with the latest change? (apologies for the prod, I wasn't sure if you noticed I had addressed your comment)

https://github.com/llvm/llvm-project/pull/114391