[clang] [Clang][SME] Add IsStreamingOrSVE2p1 (PR #75958)

[Sander de Smalen via cfe-commits]

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@@ -227,6 +227,7 @@ def IsPreservesZA             : FlagType<0x10000000000>;
 def IsReadZA                  : FlagType<0x20000000000>;
 def IsWriteZA                 : FlagType<0x40000000000>;
 def IsReductionQV             : FlagType<0x80000000000>;
+def IsStreamingOrSVE2p1       : FlagType<0x80000000000>; // Use for intrinsics that are common between sme/sme2 and sve2p1.
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sdesmalen-arm wrote:

I don't think that will work. For a bulitin defined under `let TargetGuard = "sve2p1|sme2"`; if this builtin is used in conjunction with `-mattr=+sve2,+sme2` then it should not assume that the builtin is available outside of Streaming-SVE mode because that would have required `sve2p1`.

https://github.com/llvm/llvm-project/pull/75958