[clang] [CIR] Build out AST consumer patterns to reach the entry point into CIRGen (PR #91007)

[Erich Keane via cfe-commits]

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@@ -42,6 +47,14 @@ CreateFrontendBaseAction(CompilerInstance &CI) {
   StringRef Action("unknown");
   (void)Action;
 
+  auto UseCIR = CI.getFrontendOpts().UseClangIRPipeline;
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erichkeane wrote:

Coding standard doesn't allow use of 'auto' here, only when the actual type of the variable is spelled on the RHS side (see next 2 lines too).

https://github.com/llvm/llvm-project/pull/91007