[Tir]Adding detail error messages when MatchCopyPattern function is f…

…ailed. (apache#10244)

There is an error message to show the body when 'MatchCopyPattern' is failed,
but the error message not give the information why this function get failed.
Adding the detail error information to help trouble shooting.

src/tir/transforms/inject_copy_intrin.cc

@@ -45,26 +45,35 @@ class CopyIntrinInjector : public StmtMutator {
   Stmt VisitStmt_(const AttrStmtNode* op) final {
     if (op->attr_key == pragma_key_) {
       Stmt ret;
-      ICHECK(MatchCopyPattern(op->body, &ret)) << "Cannot match copy pattern of " << op->body;
+      std::string error_info;
+      ICHECK(MatchCopyPattern(op->body, &ret, &error_info))
+          << "Cannot match copy pattern. The error is " << error_info << " The body is "
+          << op->body;
       return ret;
     }
     return StmtMutator::VisitStmt_(op);
   }
 
  private:
-  bool MatchCopyPattern(Stmt stmt, Stmt* out) {
+  bool MatchCopyPattern(Stmt stmt, Stmt* out, std::string* error_info) {
     using namespace arith;
     Stmt body = stmt;
 
     // strip the loops
     std::vector<const ForNode*> loops;
     while (const ForNode* op = body.as<ForNode>()) {
-      if (!is_zero(op->min)) return false;
+      if (!is_zero(op->min)) {
+        *error_info = "the 'min' value of body 'Fonode' is 0.";
+        return false;
+      }
       loops.push_back(op);
       body = op->body;
     }
     const StoreNode* store = body.as<StoreNode>();
-    if (store == nullptr) return false;
+    if (store == nullptr) {
+      *error_info = "the 'StoreNode' of body is a nullptr.";
+      return false;
+    }
     // Expr sel_cond, sel_true_value, sel_false_value;
     // match select or if
     PVar<PrimExpr> sel_cond, sel_true_value, sel_false_value;
@@ -84,7 +93,10 @@ class CopyIntrinInjector : public StmtMutator {
     if (cast != nullptr) {
       load = cast->value.as<LoadNode>();
     }
-    if (load == nullptr) return false;
+    if (load == nullptr) {
+      *error_info = "the 'LoadNode' of body is a nullptr.";
+      return false;
+    }
     if (load->dtype.lanes() != 1) return false;
     Array<Var> loop_vars;
     for (const ForNode* op : loops) {
@@ -109,7 +121,10 @@ class CopyIntrinInjector : public StmtMutator {
     if (has_cond) {
       Array<PrimExpr> clip_bound = arith::DetectClipBound(sel_cond.Eval(), loop_vars);
       pad_value = sel_false_value.Eval();
-      if (clip_bound.size() == 0) return false;
+      if (clip_bound.size() == 0) {
+        *error_info = "the size of clip bound is 0.";
+        return false;
+      }
       ICHECK_EQ(src_shape.size(), loop_vars.size());
       ICHECK_EQ(clip_bound.size(), loop_vars.size() * 2);
       for (size_t i = 0; i < src_shape.size(); ++i) {
@@ -150,7 +165,10 @@ class CopyIntrinInjector : public StmtMutator {
     Buffer src = Buffer(load->buffer_var, load->dtype, src_shape, src_strides, src_elem_offset,
                         load->buffer_var->name_hint, 0, 0, kDefault);
     *out = flower_copy_fromto_(src, dst, pad_before, pad_after, pad_value);
-    ICHECK(out->defined()) << "flower function did not return correct stmt";
+    if (!out->defined()) {
+      *error_info = "flower function did not return correct stmt";
+      return false;
+    }
     return true;
   }