[llvm] [StructuralHash] Refactor (PR #112621)

[Aiden Grossman via llvm-commits]

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@@ -121,14 +148,17 @@ class StructuralHashImpl {
       // This random value acts as a block header, as otherwise the partition of
       // opcodes into BBs wouldn't affect the hash, only the order of the
       // opcodes
-      hash(45798);
+      Hashes.emplace_back(45798);
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boomanaiden154 wrote:

`stable_hash_name` is not `constexpr`, so might impose a reasonable runtime performance penalty if the optimizer isn't able to optimize everything and constant fold it all (which seems like it could be unlikely).

I would still prefer moving the values to named constants, unless there's some other reason I'm missing to do it this way.

https://github.com/llvm/llvm-project/pull/112621