llvm-project

d07322bd - [AArch64][SME] Propagate desired ZA states in the MachineSMEABIPass

[AArch64][SME] Propagate desired ZA states in the MachineSMEABIPass This patch adds a propagation step to the MachineSMEABIPass that propagates desired ZA states forwards/backwards (from predecessors to successors, or vice versa). The aim of this is to pick better ZA states for edge bundles, as when many (or all) blocks in a bundle do not have a preferred ZA state, the ZA state assigned to a bundle can be less than ideal. An important case is nested loops, where only the inner loop has a preferred ZA state. Here we'd like to propagate the ZA state up from the inner loop to the outer loops (to avoid saves/restores in any loop). Change-Id: I39f9c7d7608e2fa070be2fb88351b4d1d0079041