[Unity][Graph matching] Improved matching algorithm and implementation

include/tvm/relax/dataflow_matcher.h

@@ -51,19 +51,12 @@ Optional<Map<DFPattern, Expr>> ExtractMatchedExpr(
 
 /**
  * \brief Match a sub-graph in a DataflowBlock with a graph of patterns and return the mapping.
- * \note This algorithm returns the first matched sub-graph. Use `start_hint` to specify the
- * starting point of the matching so that we can distinguish multiple matches.
- *
  * \param ctx The graph-wise patterns.
  * \param dfb The function to match.
- * \param start_hint The starting point expression to match to distinguish multiple matches.
- * \param must_include_hint If start_hint is given, the return pattern must include start_hint.
  * \return Matched patterns and corresponding bound variables
  */
 TVM_DLL Optional<Map<DFPattern, Var>> MatchGraph(const PatternContext& ctx,
-                                                 const DataflowBlock& dfb,
-                                                 Optional<Var> start_hint = NullOpt,
-                                                 bool must_include_hint = false);
+                                                 const DataflowBlock& dfb);
 
 }  // namespace relax
 }  // namespace tvm

python/tvm/relax/dpl/context.py

@@ -17,7 +17,7 @@
 
 """The Graph Matching Context Manager for Dataflow Pattern Language."""
 
-from typing import Optional, Dict
+from typing import Dict
 
 import tvm
 from ..expr import DataflowBlock, Var
@@ -63,8 +63,6 @@ def current() -> "PatternContext":
     def match_dfb(
         self,
         dfb: DataflowBlock,
-        start_hint: Optional[Var] = None,
-        must_include_hint: bool = False,
     ) -> Dict[DFPattern, Var]:
         """
         Match a DataflowBlock via a graph of DFPattern and corresponding constraints
@@ -73,14 +71,10 @@ def match_dfb(
         ----------
         dfb : DataflowBlock
             The DataflowBlock to match
-        start_hint : Optional[Var], optional
-            Indicating the starting expression to match, by default None
-        must_include_hint : bool, optional
-            Whether the start_hint expression must be matched, by default False
 
         Returns
         -------
         Dict[DFPattern, Var]
             The mapping from DFPattern to matched expression
         """
-        return ffi.match_dfb(self, dfb, start_hint, must_include_hint)  # type: ignore
+        return ffi.match_dfb(self, dfb)  # type: ignore