[clang] [CIR] Initial implementation of lowering CIR to MLIR (PR #127835)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -2958,6 +2958,8 @@ defm clangir : BoolFOption<"clangir",
   BothFlags<[], [ClangOption, CC1Option], "">>;
 def emit_cir : Flag<["-"], "emit-cir">, Visibility<[ClangOption, CC1Option]>,
   Group<Action_Group>, HelpText<"Build ASTs and then lower to ClangIR">;
+def emit_cir_mlir : Flag<["-"], "emit-cir-mlir">, Visibility<[CC1Option]>, Group<Action_Group>,
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bcardosolopes wrote:

I wasn't aware of the conflict with `emit-mlir` for the flag, bummer. That changes how we should do things in the incubator and make it easier for upstreaming. If we add the `_EQ` version of the flag I guess it's not hard to redirect the flat `-emit-mlir` to expand to `-emit-mlir=<...>` with the proper FIR / CIR or MLIR dialect style in question.

https://github.com/llvm/llvm-project/pull/127835