[clang] [Clang][AMDGPU] Stop defaulting to `one-as` for all atomic scopes (PR #120095)

[via cfe-commits]

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@@ -537,7 +537,11 @@ AMDGPUTargetCodeGenInfo::getLLVMSyncScopeID(const LangOptions &LangOpts,
     break;
   }
 
-  if (Ordering != llvm::AtomicOrdering::SequentiallyConsistent) {
+  // OpenCL assumes by default that atomic scopes are per-address space for
+  // non-sequentially consistent operations.
+  if (Scope >= SyncScope::OpenCLWorkGroup &&
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b-sumner wrote:

> > less friction to just leave it there.
> 
> This is how we just end up with an ever-growing pile of garbage nobody understands. Just rip it out.

We'd better make sure we're not breaking OpenCL conformance before we do any ripping.

https://github.com/llvm/llvm-project/pull/120095