[llvm] [AArch64][Codegen]Transform saturating smull to sqdmulh (PR #143671)

[Nashe Mncube via llvm-commits]

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@@ -20717,6 +20717,83 @@ static SDValue performBuildVectorCombine(SDNode *N,
   return SDValue();
 }
 
+// A special combine for the vqdmulh family of instructions.
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nasherm wrote:

Done

https://github.com/llvm/llvm-project/pull/143671