[llvm] [SPARC] Use hardware byteswapper when we have V9 (PR #191720)

[Sergei Barannikov via llvm-commits]

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@@ -3218,13 +3255,109 @@ SDValue SparcTargetLowering::PerformBITCASTCombine(SDNode *N,
   return SDValue();
 }
 
+SDValue SparcTargetLowering::PerformBSWAPCombine(SDNode *N,
+                                                 DAGCombinerInfo &DCI) const {
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s-barannikov wrote:

It might make sense to enable these optimizations post-legalize-ops only (see `DCI.isAfterLegalizeDAG()`, to give generic DAGCombiner a chance to fold them with other operations before we convert it to target-specific nodes.


https://github.com/llvm/llvm-project/pull/191720