[clang] [CIR] Add support for the IdiomRecognizer pass (PR #208854)

[Rithik Sharma via cfe-commits]

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@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -clangir-enable-idiom-recognizer -emit-cir -mmlir --mlir-print-ir-after=cir-idiom-recognizer %s -o /dev/null 2>&1 | FileCheck %s --implicit-check-not=cir.std.
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SharmaRithik wrote:

Not this one. Combining it would bring back the macro Eric asked us to drop, since the void find and the int find take the same parameters. The namespace tests did fold into the guards file though.

https://github.com/llvm/llvm-project/pull/208854