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

[Erich Keane via cfe-commits]

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+// 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.
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -DVOID_RESULT -fclangir -clangir-enable-idiom-recognizer -emit-cir -mmlir --mlir-print-ir-after=cir-idiom-recognizer %s -o /dev/null 2>&1 | FileCheck %s --check-prefix=VOID --implicit-check-not=cir.std.
+
+// Each call satisfies every recognizer check except the one guard it pins,
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erichkeane wrote:

What does this comment mean? It isn't adding anything here...

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