[PATCH] D154306: [InstCombine] Generalise ((x1 ^ y1) | (x2 ^ y2)) == 0 transform to more than two pairs of variables

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp:2060
+
+    auto *BO = dyn_cast<BinaryOperator>(OrOp0);
+    if (BO && BO->getOpcode() == BinaryOperator::Or) {
----------------
goldstein.w.n wrote:
> Shouldn't we also be able to chase OrOp1 (if it doesn't match `Xor`).
> 
> Figure it should be something along the lines of:
> ```
> if(match(Op0, Xor) && match(Op1, Xor)) {
>  // Base Case
> }
> else if(match(Op0, Xor)) {
>  // Chase Op1
> }
> else if(match(Op1, Xor)) {
>  // Chase Op1
> }
> else {
>  break;
> }
> ```
Err third condition should be "Chase Op0"


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D154306/new/

https://reviews.llvm.org/D154306