[clang] [llvm] [AArch64] Implement the atomic store with hint intrinsic (PR #198316)

[via cfe-commits]

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@@ -2885,6 +2885,19 @@ bool AArch64InstrInfo::isStridedAccess(const MachineInstr &MI) {
   });
 }
 
+AArch64AtomicStoreHint
+AArch64InstrInfo::decodeAtomicHintFlags(MachineMemOperand::Flags MMOFlags) {
+  unsigned AtomicHint = 0;
+  if (MMOFlags & MOAtomicHintBit0)
+    AtomicHint += 0b1;
+  if (MMOFlags & MOAtomicHintBit1)
+    AtomicHint += 0b10;
+
+  if (!isValidAArch64AtomicHintValue(AtomicHint))
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Lukacma wrote:

I would assume that flags would always be set to valid value (or HINT_NONE) why is this check necessary?

https://github.com/llvm/llvm-project/pull/198316