[llvm] [InlineCost] Consider the default branch when calculating cost (PR #77856)

[Quentin Dian via llvm-commits]

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@@ -65,7 +65,8 @@ class TargetTransformInfoImplBase {
     (void)PSI;
     (void)BFI;
     JTSize = 0;
-    return SI.getNumCases();
+    bool HasDefault = !SI.defaultDestUndefined();
+    return SI.getNumCases() + HasDefault;
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DianQK wrote:

I think it's good semantics for `getNumCases` to not include default branches. I'll update the code to give similar semantics to `getEstimatedNumberOfCaseClusters`. :)

https://github.com/llvm/llvm-project/pull/77856