Refactor to use FactorAxesPair.assignTo api for assigning the picked …

…axes to the picked factor.

PiperOrigin-RevId: 696809790

shardy/dialect/sdy/transforms/export/insert_explicit_reshards.cc

@@ -197,6 +197,10 @@ struct FactorAxesPair {
   bool operator==(const FactorAxesPair& rhs) const {
     return factorIndex == rhs.factorIndex && axisRefs == rhs.axisRefs;
   }
+
+  void assignTo(AxesPerFactor& axesPerFactor) {
+    axesPerFactor[factorIndex] = llvm::to_vector(axisRefs);
+  }
 };
 
 struct FactorAxesPairInfo : public llvm::DenseMapInfo<FactorAxesPair> {
@@ -251,8 +255,7 @@ AxesPerFactor findCommonAxesUsingMajorityVoteHeuristic(
   // TODO(enver): Assign an axis to a factor immediately if the count is more
   // than floor(n/2) where n is the number of tensors.
   while (maxCount > 0) {
-    factorAxisRefs[bestFactorAxes.factorIndex] =
-        llvm::to_vector(bestFactorAxes.axisRefs);
+    bestFactorAxes.assignTo(factorAxisRefs);
     // TODO(enver): Tie-breaking currently depends on the order of iteration.
     // Consider some heuristic for breaking ties.
     // Invalidate axes that overlaps with the picked one across all unseen