[llvm-branch-commits] [CodeGen] Add target hook shouldReMaterializeTrivialRegDef (PR #148429)

[Tomer Shafir via llvm-branch-commits]

https://github.com/tomershafir created https://github.com/llvm/llvm-project/pull/148429

Adds a target hook `shouldReMaterializeTrivialRegDef` that enables target to specify wether rematerialization of the copy is beneficial. This patch also provide an implementation for AArch64 based on the new subtarget hooks `canLowerToZeroCycleReg[Move|Zeroing]`.

It prepares for a register coalescer optimization to prevent rematerialization of moves where the target supports ZCM.