[llvm] [Xtensa] Implement Xtensa S32C1I Option and atomics lowering. (PR #137134)

[Matt Arsenault via llvm-commits]

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@@ -117,6 +118,10 @@ class XtensaTargetLowering : public TargetLowering {
                       const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
                       SelectionDAG &DAG) const override;
 
+  bool shouldInsertFencesForAtomic(const Instruction *I) const override {
+    return true;
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arsenm wrote:

Should get test coverage in test/Transforms/AtomicExpand 

https://github.com/llvm/llvm-project/pull/137134