[llvm] [RISCV] Make more vector pseudos commutable (PR #88379)

[Pengcheng Wang via llvm-commits]

================
@@ -6224,9 +6232,9 @@ foreach vti = AllIntegerVectors in {
 //===----------------------------------------------------------------------===//
 // 11.2. Vector Widening Integer Add/Subtract
 //===----------------------------------------------------------------------===//
-defm PseudoVWADDU : VPseudoVWALU_VV_VX;
+defm PseudoVWADDU : VPseudoVWALU_VV_VX<Commutable=1>;
 defm PseudoVWSUBU : VPseudoVWALU_VV_VX;
-defm PseudoVWADD  : VPseudoVWALU_VV_VX;
+defm PseudoVWADD  : VPseudoVWALU_VV_VX<Commutable=1>;
 defm PseudoVWSUB  : VPseudoVWALU_VV_VX;
 defm PseudoVWADDU : VPseudoVWALU_WV_WX;
----------------
wangpc-pp wrote:

These are the widening variants with `2*SEW` source, they are not commutable.
```asm
# Widening unsigned integer add/subtract, 2*SEW = 2*SEW +/- SEW
vwaddu.wv vd, vs2, vs1, vm # vector-vector
vwaddu.wx vd, vs2, rs1, vm # vector-scalar
# Widening signed integer add/subtract, 2*SEW = 2*SEW +/- SEW
vwadd.wv vd, vs2, vs1, vm # vector-vector
vwadd.wx vd, vs2, rs1, vm # vector-scalar
```

https://github.com/llvm/llvm-project/pull/88379