[llvm] [PowerPC] replace vector compare equal to with vector compare greater than (PR #150422)

[Lei Huang via llvm-commits]

================
@@ -4570,6 +4570,17 @@ bool PPCDAGToDAGISel::trySETCC(SDNode *N) {
     if (Subtarget->hasSPE())
       return false;
 
+    // Optimise 'Not equal to zero-vector' comparisons using 'Greater than or
+    // less than' operators. Example: Consider k to be any non-zero positive
+    // value.
+    // for k != 0, change SETNE to SETUGT (k > 0)
+    // for 0 != k, change SETNE to SETULT (0 < k)
----------------
lei137 wrote:

```suggestion
    // Optimize 'Not equal to zero-vector' comparisons to 'Greater than or
    // less than' operators. 
    // Example: Consider k to be any non-zero positive value
    // * for k != 0, change SETNE to SETUGT (k > 0)
    // * for 0 != k, change SETNE to SETULT (0 < k)
```

https://github.com/llvm/llvm-project/pull/150422