[clang] [Clang] Instantiate constexpr function when they are needed. (PR #173537)

[Timm Baeder via cfe-commits]

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@@ -20707,6 +20739,8 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
                     : EvaluationMode::ConstantFold);
   Info.setEvaluatingDecl(VD, Value);
   Info.InConstantContext = IsConstantInitialization;
+  Info.TryConstantInitialization =
+      !VD->isConstexpr() && !VD->hasAttr<ConstInitAttr>();
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tbaederr wrote:

Doesn't this mean we only do it for initializers? What if I want to call such a function in a `static_assert` call? Shouldn't that work too?

https://github.com/llvm/llvm-project/pull/173537