[llvm] [AArch64][SME] Propagate desired ZA states in the MachineSMEABIPass (PR #149510)

[Sander de Smalen via llvm-commits]

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@@ -918,6 +987,43 @@ bool MachineSMEABI::runOnMachineFunction(MachineFunction &MF) {
       getAnalysis<EdgeBundlesWrapperLegacy>().getEdgeBundles();
 
   FunctionInfo FnInfo = collectNeededZAStates(SMEFnAttrs);
+
+  if (OptLevel != CodeGenOptLevel::None) {
+    // Propagate desired states forwards then backwards. We propagate forwards
+    // first as this propagates desired states from inner to outer loops.
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sdesmalen-arm wrote:

Okay, then I'd say that's worth clarifying in this paragraph or alternatively you can just remove most of this paragraph because the comments below the graph explain it better.

https://github.com/llvm/llvm-project/pull/149510