[clang] [CIR] Upstream handling for __builtin_prefetch (PR #164387)

[Andy Kaylor via cfe-commits]

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@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-cir %s -o - | FileCheck %s -check-prefix=CIR
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o - | FileCheck %s -check-prefix=LLVM
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andykaylor wrote:

```suggestion
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-cir %s -o - | FileCheck %s -check-prefix=CIR
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o - | FileCheck %s -check-prefix=LLVM
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s -check-prefix=OGCG
```
Please add OGCG checks for comparison. (BTW, this is how I noticed that we were using a different default for `locality` in CIR: https://godbolt.org/z/z9bj5391d)

https://github.com/llvm/llvm-project/pull/164387