[llvm] [AArch64][ISel] Add clmul to pmullb/t lowering (PR #180568)

[Paul Walker via llvm-commits]

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@@ -2015,6 +2015,9 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
     }
   }
 
+  if (Subtarget->hasSVE2AES())
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paulwalker-arm wrote:

This check is not sufficient because the Q variant of PMULLB/T is not universally available unless FEAT_SSVE_AES is implemented.  Please avoid using `hasSVE2AES` as that's the result of a long standing mistake.  The underlying instruction uses `hasSVEAES` combined with extra logic to account for SME.

https://github.com/llvm/llvm-project/pull/180568