[clang] [llvm] [AArch64][clang][llvm] Add ACLE `stshh` atomic store builtin (PR #181386)

[Kerry McLaughlin via cfe-commits]

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@@ -0,0 +1,12 @@
+; RUN: llc -mtriple=aarch64 -mattr=+pcdphint < %s | FileCheck %s
+
+declare void @llvm.aarch64.stshh(i64)
+
+define void @test_stshh_atomic_store(ptr %p, i32 %v) {
+; CHECK-LABEL: test_stshh_atomic_store
+; CHECK: stshh
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kmclaughlin-arm wrote:

I think it's worth checking that the  policy (`keep`) is correct too. Please can you use the `update_llc_test_checks.py` script to generate the `CHECK` lines?
It might also be worth adding another test for `strm`.

https://github.com/llvm/llvm-project/pull/181386