[clang] [llvm] [AArch64][TableGen] Define ZA, ZT0 and FPMR memory defvars (PR #154144)

[Paul Walker via cfe-commits]

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@@ -3179,9 +3217,9 @@ let TargetPrefix = "aarch64" in {
                               [IntrNoMem, IntrHasSideEffects]>;
 
   def int_aarch64_sme_za_enable
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paulwalker-arm wrote:

Thanks @Lukacma. I initially thought enabling ZA might trigger some initialisation state, similar to what happens when entering/existing streaming mode, but I see that's not the case so this seems like a sensible direction to consider once we've lock down the transition to target memory.

https://github.com/llvm/llvm-project/pull/154144