[llvm] [PowerPC] extend smaller splats into bigger splats (with fix) (PR #142194)

[zhijian lin via llvm-commits]

================
@@ -3713,30 +3713,26 @@ entry:
 define <2 x i64> @spltConst1ll() {
 ; P9BE-LABEL: spltConst1ll:
 ; P9BE:       # %bb.0: # %entry
-; P9BE-NEXT:    addis r3, r2, .LCPI65_0 at toc@ha
-; P9BE-NEXT:    addi r3, r3, .LCPI65_0 at toc@l
-; P9BE-NEXT:    lxv v2, 0(r3)
+; P9BE-NEXT:    vspltisw v2, 1
+; P9BE-NEXT:    vupklsw v2, v2
----------------
diggerlin wrote:

I am curiously , why we can not implement 
```
 vspltisw v2, 1
  vupklsw v2, v2
```

to
 `  xxspltidp v2, 1`
 directly ?
   


https://github.com/llvm/llvm-project/pull/142194