[clang] [clang] add `-fimplicit-constexpr` flag (PR #136436)

[Timm Baeder via cfe-commits]

Hana =?utf-8?q?Dusíková?= <hanicka at hanicka.net>
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In-Reply-To: <llvm.org/llvm/llvm-project/pull/136436 at github.com>


tbaederr wrote:

>  That however runs into the problem that the constant evaluator needs to be able to diagnose any invalid constructs it runs into w/o crashing, and I’m not sure it’s currently set up for that given that CheckConstexprFunctionDefinitions() rejects e.g. gotos before we ever get to the constant evaluator.

This at least shouldn't be a problem - the constant evaluator already needs to do that when e.g. the `goto` is only conditionally reachable: https://godbolt.org/z/TdYz4zP5c.

https://github.com/llvm/llvm-project/pull/136436