[NVPTX] Fix crash in libc gpu after db5d845 (#65579)

Author: ThomasRaoux

llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp

@@ -586,6 +586,11 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
     setTruncStoreAction(VT, MVT::i1, Expand);
   }
 
+  // expand extload of vector of integers.
+  setLoadExtAction({ISD::EXTLOAD, ISD::SEXTLOAD, ISD::ZEXTLOAD}, MVT::v2i16,
+                   MVT::v2i8, Expand);
+  setTruncStoreAction(MVT::v2i16, MVT::v2i8, Expand);
+
   // This is legal in NVPTX
   setOperationAction(ISD::ConstantFP, MVT::f64, Legal);
   setOperationAction(ISD::ConstantFP, MVT::f32, Legal);