[llvm] [SeparateConstOffsetFromGEP] Decompose constant xor operand if possible (PR #135788)

[Jay Foad via llvm-commits]

================
@@ -1162,6 +1202,165 @@ bool SeparateConstOffsetFromGEP::splitGEP(GetElementPtrInst *GEP) {
   return true;
 }
 
+// Helper function to check if an instruction has at least one GEP user
+bool XorToOrDisjointTransformer::hasGEPUser(const Value *V) {
+  for (const User *U : V->users()) {
+    if (isa<GetElementPtrInst>(U)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool XorToOrDisjointTransformer::dominatesAllXors(
+    BinaryOperator *BaseXor, const XorOpList &XorsInGroup) {
+  for (const auto &XorEntry : XorsInGroup) {
+    BinaryOperator *XorInst = XorEntry.first;
+    if (XorInst != BaseXor && !DT.dominates(BaseXor, XorInst)) {
----------------
jayfoad wrote:

I don't think you need the `!=` check, do you?
```suggestion
    if (!DT.dominates(BaseXor, XorInst)) {
```
Also: use `all_of`?

https://github.com/llvm/llvm-project/pull/135788