masahi commented on code in PR #11050:
URL: https://github.com/apache/tvm/pull/11050#discussion_r853512468


##########
src/tir/schedule/analysis/analysis.cc:
##########
@@ -2028,5 +2035,162 @@ bool NeedsRFactorOrCrossThreadReduction(const 
tir::ScheduleState& self,   //
   }
 }
 
+TVM_REGISTER_NODE_TYPE(TensorizeInfoNode);
+
+Optional<TensorizeInfo> GetTensorizeLoopMapping(const tir::ScheduleState& self,
+                                                const tir::StmtSRef& 
block_sref,
+                                                const tir::PrimFunc& 
desc_func) {
+  arith::Analyzer analyzer;
+  const tir::BlockRealize& block = tir::GetBlockRealize(self, block_sref);
+  // Step 1. Analyze desc_func, extract its block, loops and loop vars
+  const tir::BlockRealizeNode* desc_block = nullptr;
+  std::vector<const tir::ForNode*> desc_loops;
+  std::unordered_set<const tir::VarNode*> desc_loop_vars;
+  const auto* desc_scope_realize = desc_func->body.as<tir::BlockRealizeNode>();
+  ICHECK(desc_scope_realize);
+  {
+    auto f_visit = [&desc_block, &desc_loops, &desc_loop_vars,
+                    &analyzer](const ObjectRef& obj) -> bool {
+      // Extract the block
+      if (const auto* block = obj.as<tir::BlockRealizeNode>()) {
+        desc_block = block;
+        return false;
+      }
+      // Extract loops
+      if (const auto* loop = obj.as<tir::ForNode>()) {
+        desc_loops.push_back(loop);
+        desc_loop_vars.insert(loop->loop_var.get());
+        if (!analyzer.CanProve(loop->min == 0)) {
+          return false;
+        }
+      }
+      return true;
+    };
+    tir::PostOrderVisit(desc_scope_realize->block->body, f_visit);
+    std::reverse(desc_loops.begin(), desc_loops.end());
+    ICHECK(desc_block);
+  }
+  // Step 2. Collect loops from block_sref
+  const tir::StmtSRef& scope_sref = GetScopeRoot(self, block_sref, false);
+  const tir::BlockNode* scope_block = TVM_SREF_TO_BLOCK(scope_block, 
scope_sref);
+  std::vector<const tir::ForNode*> block_loops;
+  std::unordered_set<const tir::VarNode*> block_loop_vars;
+  {
+    for (const tir::StmtSRefNode* loop_sref = block_sref->parent;; loop_sref = 
loop_sref->parent) {
+      const auto* loop = loop_sref->StmtAs<tir::ForNode>();
+      if (loop == nullptr || loop->body->IsInstance<tir::SeqStmtNode>()) {
+        break;
+      }
+      block_loops.push_back(loop);
+      block_loop_vars.insert(loop->loop_var.get());
+      if (!analyzer.CanProve(loop->min == 0)) {
+        return NullOpt;
+      }
+    }
+    std::reverse(block_loops.begin(), block_loops.end());
+  }
+  // Step 3. Map from block loops to desc block loops
+  ObjectPtr<TensorizeInfoNode> ret = make_object<TensorizeInfoNode>();
+  const int n_block_vars = block->iter_values.size();
+  const int n_desc_vars = desc_block->iter_values.size();
+  const int offset = n_block_vars - n_desc_vars;
+
+  if (offset < 0) {
+    return NullOpt;
+  }
+
+  const std::vector<IterVarType> iter_types_block = 
GetBlockVarTypes(block_sref);
+  const std::vector<IterVarType> iter_types_desc = 
GetBlockVarTypes(desc_block->block.get());
+
+  ICHECK(desc_loops.size() == static_cast<size_t>(n_desc_vars));
+  ICHECK(block_loops.size() == iter_types_block.size());
+
+  // We assume that the orders of iter_vars in the target and the desc block 
are consistent.

Review Comment:
   i.e., no matter what the permutation of loop is, we should always have
   
   ```
   i, j, k = T.axis.remap("SSR", [i0, i1, i2])
   ```
   
   for GEMM.
   
   I think this is a reasonable assumption. Correct me if I'm wrong 
@spectrometerHBH @junrushao1994 @vinx13 



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