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

[Kerry McLaughlin via cfe-commits]

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@@ -1001,6 +1004,72 @@ bool AArch64ExpandPseudo::expandStoreSwiftAsyncContext(
   return true;
 }
 
+bool AArch64ExpandPseudo::expandSTSHHAtomicStore(
+    MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI) {
+  MachineInstr &MI = *MBBI;
+  DebugLoc DL(MI.getDebugLoc());
+
+  unsigned Order = MI.getOperand(2).getImm();
+  uint64_t Policy = MI.getOperand(3).getImm();
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kmclaughlin-arm wrote:

i think this can also be unsigned now?

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