[PowerPC] Fix copy/paste error in scalar_to_vector patterns

[jsji]

Summary

https://reviews.llvm.org/D100478 refactoring added a copy/paste error
for v8i16 patterns.

[shchenz]

LGTM. Thanks for catching this issue.

llvm/lib/Target/PowerPC/PPCInstrVSX.td

 let Predicates = [HasVSX, HasDirectMove, IsBigEndian] in {
 // v16i8 scalar <-> vector conversions (BE)
 defm : ScalToVecWPermute<
   v16i8, (i32 i32:$A),
   (SUBREG_TO_REG (i64 1), MovesToVSR.BE_BYTE_0, sub_64),
   (SUBREG_TO_REG (i64 1), (MTVSRWZ $A), sub_64)>;
 defm : ScalToVecWPermute<
   v8i16, (i32 i32:$A),
-  (SUBREG_TO_REG (i64 1), MovesToVSR.BE_BYTE_0, sub_64),
+  (SUBREG_TO_REG (i64 1), MovesToVSR.BE_HALF_0, sub_64),
   (SUBREG_TO_REG (i64 1), (MTVSRWZ $A), sub_64)>;
 defm : ScalToVecWPermute<
   v4i32, (i32 i32:$A),
   (SUBREG_TO_REG (i64 1), MovesToVSR.BE_WORD_0, sub_64),
   (SUBREG_TO_REG (i64 1), (MTVSRWZ $A), sub_64)>;
 def : Pat<(v2i64 (scalar_to_vector i64:$A)),
           (v2i64 (SUBREG_TO_REG (i64 1), MovesToVSR.BE_DWORD_0, sub_64))>;
 

llvm/test/CodeGen/PowerPC/scalar_vector_test_5.ll

 ; P8LE-LABEL: scalar_to_vector_half:
 ; P8LE:       # %bb.0: # %entry
 ; P8LE-NEXT:    lhz r3, 0(r3)
 ; P8LE-NEXT:    blr
 ;
 ; P8BE-LABEL: scalar_to_vector_half:
 ; P8BE:       # %bb.0: # %entry
 ; P8BE-NEXT:    lhz r3, 0(r3)
-; P8BE-NEXT:    sldi r3, r3, 56
+; P8BE-NEXT:    sldi r3, r3, 48
 ; P8BE-NEXT:    mtfprd f0, r3
 ; P8BE-NEXT:    mffprd r3, f0
 ; P8BE-NEXT:    rldicl r3, r3, 8, 56
 ; P8BE-NEXT:    blr
 entry:
     %0 = bitcast i16* %ad to <2 x i8>*
     %1 = load <2 x i8>, <2 x i8>* %0, align 1
     %2 = extractelement <2 x i8> %1, i32 0
     ret i8 %2
 }