bpf: Support i32 in getScalarShiftAmountTy method

getScalarShiftAmount method should be implemented for eBPF backend to make
sure shift amount could still get correct type once 32-bit subregisters
support are enabled.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Yonghong Song <yhs@fb.com>
llvm-svn: 325986

llvm/lib/Target/BPF/BPFISelLowering.cpp

@@ -713,3 +713,8 @@ EVT BPFTargetLowering::getSetCCResultType(const DataLayout &, LLVMContext &,
                                           EVT VT) const {
   return getHasAlu32() ? MVT::i32 : MVT::i64;
 }
+
+MVT BPFTargetLowering::getScalarShiftAmountTy(const DataLayout &DL,
+                                              EVT VT) const {
+  return (getHasAlu32() && VT == MVT::i32) ? MVT::i32 : MVT::i64;
+}

llvm/lib/Target/BPF/BPFISelLowering.h

@@ -60,6 +60,8 @@ public:
   EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
                          EVT VT) const override;
 
+  MVT getScalarShiftAmountTy(const DataLayout &, EVT) const override;
+
 private:
   // Control Instruction Selection Features
   bool HasAlu32;