Which pass is expected to fused or combined operator in TVM

Questions
4

Now I find the function MakeFMA in src/tir/transforms/lower_intrin.cc, maybe here suits to address the combine .

353   PrimExpr MakeFMA(const PrimExpr& a, const PrimExpr& b, const PrimExpr& c, const AddNode* op) {
354     // emit fma instruction: a * b + c
355     PrimExpr lhs = SwapBroadcastCast(a);
356     PrimExpr rhs = SwapBroadcastCast(b);
357 
358     if (fma_ != nullptr && op->dtype.is_float()) {
359       PrimExpr r = fma_(Call(op->dtype, builtin::fma(), {lhs, rhs, c}));
360       if (r.defined()) return this->VisitExpr(r);
361     } else {
362       if (!lhs.same_as(a) || !rhs.same_as(b)) {
363         PrimExpr mul = this->VisitExpr(Mul(lhs, rhs));
364         return Add(mul, this->VisitExpr(c));
365       }
366     }
367     return IRMutatorWithAnalyzer::VisitExpr_(op);
368   }