[llvm] [llvm] fix few copypaste typos (PR #119881)

[David Green via llvm-commits]

davemgreen wrote:

The AArch64 part certainly does look wrong. We should add a test case and probably separate that out into a different review, to separate the different issues. Are you OK to do that, or are you happy for me to put it together?

Here's a test I came up with for it:
```
define i64 @add_v4i32_v4i64_zsext(<4 x i32> %xi) {
; CHECK-LABEL: add_v4i32_v4i64_zsext:
; CHECK:       // %bb.0: // %entry
; CHECK-NEXT:    ushll v1.2d, v0.2s, #0
; CHECK-NEXT:    saddw2 v0.2d, v1.2d, v0.4s
; CHECK-NEXT:    addp d0, v0.2d
; CHECK-NEXT:    fmov x0, d0
; CHECK-NEXT:    ret
entry:
  %x = shufflevector <4 x i32> %xi, <4 x i32> %xi, <2 x i32> <i32 0, i32 1>
  %y = shufflevector <4 x i32> %xi, <4 x i32> %xi, <2 x i32> <i32 2, i32 3>
  %xx = zext <2 x i32> %x to <2 x i64>
  %yy = sext <2 x i32> %y to <2 x i64>
  %zz = add <2 x i64> %xx, %yy
  %z = call i64 @llvm.vector.reduce.add.v2i64(<2 x i64> %zz)
  ret i64 %z
}
```

https://github.com/llvm/llvm-project/pull/119881