【CINN】Add utils and simplify corner case (#71278)

liuruyan · web-flow · commit a5d4b6724ff7 · 2025-02-26T16:45:36.000+08:00
* add corner case

* polish code

* polish code
diff --git a/paddle/cinn/common/ir_util.cc b/paddle/cinn/common/ir_util.cc
@@ -812,5 +812,43 @@ std::optional<ir::IndexExpr> SimplifyComplexMod(const ir::IndexExpr &lhs,
   }
   return std::nullopt;
 }
+
+bool CheckPattern(const ir::IndexExpr &expr,
+                  const ir::IndexExpr &pattern,
+                  std::unordered_map<std::string, ir::IndexExpr> *map) {
+  // pattern may include Var to match any expr.
+  if (expr.node_type() != pattern.node_type() &&
+      pattern.node_type() != ir::IrNodeTy::_Var_)
+    return false;
+  switch (pattern.node_type()) {
+    case ir::IrNodeTy::Add:
+    case ir::IrNodeTy::Sub:
+    case ir::IrNodeTy::Mul:
+    case ir::IrNodeTy::Div:
+    case ir::IrNodeTy::Mod:
+    case ir::IrNodeTy::Min:
+    case ir::IrNodeTy::Max: {
+      return CheckPattern(expr.operand(0), pattern.operand(0), map) &&
+             CheckPattern(expr.operand(1), pattern.operand(1), map);
+    }
+    case ir::IrNodeTy::_Var_: {
+      auto it = map->find(pattern.As<ir::_Var_>()->name);
+      if (it != map->end()) {
+        return expr == it->second;
+      } else {
+        map->insert(std::make_pair(pattern.As<ir::_Var_>()->name, expr));
+        return true;
+      }
+    }
+    case ir::IrNodeTy::IntImm: {
+      return expr.As<ir::IntImm>()->value == pattern.As<ir::IntImm>()->value;
+    }
+    default:
+      PADDLE_THROW(::common::errors::InvalidArgument(
+          "Unsupported type of expr in CheckPattern which is: %s", expr));
+  }
+
+  return false;
+}
 }  // namespace common
 }  // namespace cinn
diff --git a/paddle/cinn/common/ir_util.h b/paddle/cinn/common/ir_util.h
@@ -414,5 +414,23 @@ std::optional<ir::IndexExpr> DivByPartMul(const ir::IndexExpr &lhs,
  */
 std::optional<ir::IndexExpr> SimplifyComplexMod(const ir::IndexExpr &lhs,
                                                 const ir::IndexExpr &rhs);
+
+/*!
+ * \brief Check whether the expression matches the pattern.
+ * \param expr The expression to be checked.
+ * \param pattern The pattern to be matched. which includes some variables.
+ * \param map return the matched variables.
+ * \return A boolean value indicating whether `expr` is matched.
+ *
+ * For example:
+ * 1. (i / S0 * S0 + i % (S0 * S1)) % S0 matched by a / b * b + a % (b * c)
+ *    with map = {a: i, b: S0, c: S1}
+ * 2. S0 + 5 matched by a + 5 with map = {a: S0, b: 5}
+ *
+ * Note: a * b and b * a is two different pattern.
+ */
+bool CheckPattern(const ir::IndexExpr &expr,
+                  const ir::IndexExpr &pattern,
+                  std::unordered_map<std::string, ir::IndexExpr> *map);
 }  // namespace common
 }  // namespace cinn
diff --git a/paddle/cinn/common/simplify_special_pattern.cc b/paddle/cinn/common/simplify_special_pattern.cc
@@ -241,6 +241,39 @@ std::optional<ir::IndexExpr> AddMulCornerCase(
   return res;
 }
 
+// S0 / (S1 * S2) * S2 + S0 % (S1 * S2) / S1 ===>  S0 / S1
+std::optional<ir::IndexExpr> DivMulAddModDivCase(const ir::IndexExpr& lhs,
+                                                 const ir::IndexExpr& rhs) {
+  ir::Var a = ir::Var("a");
+  ir::Var b = ir::Var("b");
+  ir::Var c = ir::Var("c");
+  ir::Var f = ir::Var("f");
+  std::unordered_map<std::string, ir::IndexExpr> map;
+
+  ir::IndexExpr pattern = f / c * a + f % c / b;
+
+  auto flatten = GetFlattenExprs<ir::Add>(lhs);
+  ir::IndexExpr res = ir::IndexExpr(rhs->type(), 0);
+  bool find = false;
+  for (const auto& expr : flatten) {
+    if (!find) {
+      ir::IndexExpr cand = ir::Add::Make(expr, rhs);
+      map.clear();
+      // Check if the pattern is matched
+      if (CheckPattern(cand, pattern, &map) &&
+          map.at("c") == map.at("a") * map.at("b")) {
+        ir::IndexExpr simplied = map.at("f") / map.at("b");
+        res = res.defined() ? res + simplied : simplied;
+        find = true;
+        continue;
+      }
+    }
+    res = res.defined() ? ir::Add::Make(res, expr) : expr;
+  }
+  if (find) return res;
+  return std::nullopt;
+}
+
 // (S0 + S1 - (S0 + S1) % S2) % S2 == 0
 // (S0 + S1 - (S0 + S1) % S2) / S2 == (S0 + S1) / S2
 std::optional<ir::IndexExpr> SubModCornerCase(const ir::IndexExpr& lhs,
@@ -322,6 +355,7 @@ std::optional<ir::IndexExpr> SimplifyAddCornerCase(const ir::IndexExpr& lhs,
                                                    const ir::IndexExpr& rhs) {
   if (auto res = DivMulAddModCornerCase(lhs, rhs)) return res.value();
   if (auto res = AddMulCornerCase(lhs, rhs)) return res.value();
+  if (auto res = DivMulAddModDivCase(lhs, rhs)) return res.value();
   // Add other corner cases
   return std::nullopt;
 }
diff --git a/test/cpp/pir/cinn/adt/index_expr_test.cc b/test/cpp/pir/cinn/adt/index_expr_test.cc
@@ -143,6 +143,9 @@ TEST_F(TestIndexExpr, IndexExpr_3) {
   ir::Expr q16 =
       ((S4 * 256 + S5) / S6 / S7 * S7 + (S4 * 256 + S5) / S6 % S7) * S6 +
       (S4 * 256 + S5) % S6;
+  ir::Expr q17 = S4 / (S5 * S6) * S6 + S4 % (S5 * S6) / S5;
+  ir::Expr q18 = (S4 * 1024 + S5 * 256 + S6) / 2097152 * 32 +
+                 (S4 * 1024 + S5 * 256 + S6) % 2097152 / 65536;
 
   // `Div` corner cases
   ir::Expr q6 = (S4 % S5 - S4) / S5;
@@ -174,6 +177,9 @@ TEST_F(TestIndexExpr, IndexExpr_3) {
             ir::IndexExpr((S4 * 256 + S5 + S6 * 1024)) % 25088);
   EXPECT_EQ(q16.as_index().Normalize(ir::IndexExpr::OptLevel::Level2),
             ir::IndexExpr(S4 * 256 + S5));
+  EXPECT_EQ(q17.as_index().Normalize(), ir::IndexExpr(S4 / S5));
+  EXPECT_EQ(q18.as_index().Normalize(),
+            ir::IndexExpr((S4 * 1024 + S5 * 256 + S6) / 65536));
 }
 
 TEST_F(TestIndexExpr, Change_Seq_Of_Div_Mod) {
@@ -495,5 +501,37 @@ TEST_F(TestIndexExpr, CommonFactor) {
          S2) *
         (((((S5 + S9) + S21) + S17) + S13) + S1))));
 }
+
+TEST_F(TestIndexExpr, TestCheckPattern) {
+  ir::Var a = ir::Var("a");
+  ir::Var b = ir::Var("b");
+  ir::Var f = ir::Var("f");
+
+  ir::Var S0 = ir::Var("S0");
+  ir::Var S1 = ir::Var("S1");
+  ir::Var S2 = ir::Var("S2");
+  ir::Var S3 = ir::Var("S3");
+  ir::Var S4 = ir::Var("S4");
+  ir::Var S5 = ir::Var("S5");
+  ir::Var S6 = ir::Var("S6");
+  ir::Var S7 = ir::Var("S7");
+  ir::Var S8 = ir::Var("S8");
+  ir::Var S9 = ir::Var("S9");
+
+  ir::IndexExpr pattern = f / (a * b) * b + f % (a * b) / a;
+  ir::IndexExpr pattern1 = f / (a * b) * a + f % (a * b) / b;
+  ir::IndexExpr e = (S0 * (S1 + S2) + S1 * S2 + S2) / (S4 * S5) * S5 +
+                    (S0 * (S1 + S2) + S1 * S2 + S2) % (S4 * S5) / S4;
+  ir::IndexExpr e1 = (S0 * (S1 + S2) + S1 * S2 + S2) / (S4 * S5) * S4 +
+                     (S0 * (S1 + S2) + S1 * S2 + S2) % (S4 * S5) / S5;
+  std::unordered_map<std::string, ir::IndexExpr> map;
+  EXPECT_TRUE(common::CheckPattern(e, pattern, &map));
+  map.clear();
+  EXPECT_FALSE(common::CheckPattern(e, pattern1, &map));
+  map.clear();
+  EXPECT_FALSE(common::CheckPattern(e1, pattern, &map));
+  map.clear();
+  EXPECT_TRUE(common::CheckPattern(e1, pattern1, &map));
+}
 }  // namespace common
 }  // namespace cinn
