[mlir][sparse] Simplifying Merger::expContainsTensor

[wrengr]

Summary

expContainsTensor used to call expIsTensor to short-circuit the recursive calls; however, the very first thing expContainsTensor does is to check expIsTensor, so the short-circuiting code just causes the function to check that condition redundantly.

Depends On D146684

[wrengr]

rebase

[wrengr]

rebasing for the postponement splitting of D146684

[wrengr]

rebase

mlir/lib/Dialect/SparseTensor/Utils/Merger.cpp

 bool Merger::onlyDenseDiff(LatPointId i, LatPointId j) const {
   BitVector tmp(lat(j).bits);
   tmp ^= lat(i).bits;
   return !hasAnySparse(tmp) && !hasSparseIdxReduction(tmp);
 }
 
 bool Merger::expContainsTensor(ExprId e, TensorId t) const {
   const auto &expr = exp(e);
+  // First we check `expIsTensor`.
   if (expr.kind == TensorExp::Kind::kTensor)
     return expr.tensor == t;
 
   switch (getExpArity(expr.kind)) {
   case ExpArity::kNullary:
     return false;
   case ExpArity::kUnary: {
     const ExprId e0 = expr.children.e0;
-    if (expIsTensor(e0, t))
-      return true;
     return expContainsTensor(e0, t);
   }
   case ExpArity::kBinary: {
     const ExprId e0 = expr.children.e0;
     const ExprId e1 = expr.children.e1;
-    if (expIsTensor(e0, t) || expIsTensor(e1, t))
-      return true;
     return expContainsTensor(e0, t) || expContainsTensor(e1, t);
   }
   }
   llvm_unreachable("unexpected arity");
 }
 
 bool Merger::hasNegateOnOut(ExprId e) const {
   const auto &expr = exp(e);