[clang] [Clang][Driver] Add new flags to control IR verification (PR #68172)

[Matheus Izvekov via cfe-commits]

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@@ -146,6 +146,13 @@ Non-comprehensive list of changes in this release
 
 New Compiler Flags
 ------------------
+* ``-fverify-intermediate-code`` and it's complement ``-fno-verify-intermediate-code``.
+  Enables or disables verification of the generated LLVM IR.
+  It's strongly encouraged to enable this verification, as it can catch hard to
+  find code generation bugs.
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mizvekov wrote:

Strongly recommending doing something that is opt-in, versus making that something opt-out, versus forcing it, all have different trade-offs, and I am not trying to make any blank statements here that any of them don't make sense.

I think keeping it opt-in, but recommending people do so, is sensible progressive political approach, especially when this choice can have financial costs on them :)

https://github.com/llvm/llvm-project/pull/68172