[clang] [CIR] Implement 'loop hint' lowering (PR #232975)

[Erich Keane via cfe-commits]

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@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefixes=CIR,CXX17
+// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t-98.cir
+// RUN: FileCheck --input-file=%t-98.cir %s --check-prefixes=CIR,CXX98
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erichkeane wrote:

No, we're not doing any lowering yet!  The intent is for me to work top-down, right now I think I need to do a flatten-pass to get the loops flattened right and these passed on, plus lowering as a separate patch.  I thought about doing 1 attribute top-to-bottom, but moving the work from classic meant I had all of the work for CIRGen in place already, so it made more sense to do it all at once.

BUT the rest made this a big patch unfortunately.

https://github.com/llvm/llvm-project/pull/232975