[llvm] [X86] Ensure that bit reversals of byte vectors are properly lowered on pure GFNI targets (PR #148304)

[Tobias Decking via llvm-commits]

================
@@ -1328,6 +1328,7 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
     setOperationAction(ISD::BITREVERSE, MVT::i16, Custom);
     setOperationAction(ISD::BITREVERSE, MVT::i32, Custom);
     setOperationAction(ISD::BITREVERSE, MVT::i64, Custom);
+    setOperationAction(ISD::BITREVERSE, MVT::v16i8, Custom);
----------------
TDecking wrote:

The missing `useSoftFloat` call has been added.

https://github.com/llvm/llvm-project/pull/148304