[clang] [flang] [flang][driver] Separate the actions of the `-emit-fir` and `-emit-mlir` options (PR #139857)

[Tarun Prabhu via cfe-commits]

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@@ -635,6 +635,49 @@ void CodeGenAction::lowerHLFIRToFIR() {
   }
 }
 
+void CodeGenAction::lowerFIRToMLIR() {
+  assert(mlirModule && "The MLIR module has not been generated yet.");
+
+  CompilerInstance &ci = this->getInstance();
+  CompilerInvocation &invoc = ci.getInvocation();
+  const CodeGenOptions &opts = invoc.getCodeGenOpts();
+  const auto &mathOpts = invoc.getLoweringOpts().getMathOptions();
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tarunprabhu wrote:

Could we use a more concrete type instead of `auto` here?

https://github.com/llvm/llvm-project/pull/139857