diff --git a/src/pass/storage_rewrite.cc b/src/pass/storage_rewrite.cc
index 134676c287e1c..065894871ab9e 100644
--- a/src/pass/storage_rewrite.cc
+++ b/src/pass/storage_rewrite.cc
@@ -564,11 +564,14 @@ class StoragePlanRewriter : public IRMutator {
           Expr combo_size;
           for (const Allocate* op : e->allocs) {
             Expr sz = arith::ComputeReduce<Mul>(op->extents, make_const(Int(32), 1));
+            auto nbits = op->type.bits() * op->type.lanes();
             if (const auto* imm = sz.as<IntImm>()) {
-              sz =  make_const(Int(64), imm->value);
+              if (imm->value > std::numeric_limits<int>::max() / nbits) {
+                sz = make_const(Int(64), imm->value);
+              }
             }
             // transform to bits
-            auto sz_nbits = sz * (op->type.bits() * op->type.lanes());
+            auto sz_nbits = sz * nbits;
             if (combo_size.defined()) {
               combo_size = max(combo_size, sz_nbits);
             } else {
@@ -581,7 +584,7 @@ class StoragePlanRewriter : public IRMutator {
           combo_size = combo_size / type_bits;
           // round up for can not divided
           if (!divided) {
-             combo_size = combo_size + make_const(Int(64), 1);
+            combo_size = combo_size + make_const(Int(32), 1);
           }
           combo_size = ir::Simplify(combo_size);
           e->new_alloc = Allocate::make(