Solve on canonical simplification side

Author: MasterJH5574

src/arith/canonical_simplify.cc

@@ -335,6 +335,8 @@ class SumExprNode : public CanonicalExprNode {
    * \return whether the cast can be safely pushed to children
    */
   bool CanPushCastToChildren(DataType dtype, Analyzer* analyzer) const {
+    bool is_min_value = dtype.bits() == 64 ? base == std::numeric_limits<int64_t>::lowest()
+                                           : base == -(1LL << (dtype.bits() - 1));
     // cast(dtype, arg_1 + arg_2 + ... arg_n) ==
     // cast(dtype, arg_1) + ... + cast(dtype, arg_n)
     // iff it is an upcast (dtype.bits >= self.dtype.bits) or all of
@@ -351,7 +353,7 @@ class SumExprNode : public CanonicalExprNode {
         }
       }
     }
-    if (base > 0) {
+    if (base > 0 || is_min_value) {
       res = res + make_const(dtype, base);
       if (!CastIsSafe(dtype, res, analyzer)) {
         return false;
@@ -366,7 +368,7 @@ class SumExprNode : public CanonicalExprNode {
         }
       }
     }
-    if (base < 0) {
+    if (base < 0 && !is_min_value) {
       res = res - make_const(dtype, -base);
       if (!CastIsSafe(dtype, res, analyzer)) {
         return false;
@@ -497,14 +499,16 @@ class SumExprNode : public CanonicalExprNode {
     return args;
   }
   static PrimExpr Normalize_(DataType dtype, const std::vector<SplitExpr>& args, int64_t base) {
+    bool is_min_value = dtype.bits() == 64 ? base == std::numeric_limits<int64_t>::lowest()
+                                           : base == -(1LL << (dtype.bits() - 1));
     // Positive scales first
     PrimExpr res = make_const(dtype, 0);
     for (size_t i = 0; i < args.size(); ++i) {
       if (args[i]->scale > 0) {
         res = res + args[i]->Normalize();
       }
     }
-    if (base > 0) {
+    if (base > 0 || is_min_value) {
       res = res + make_const(dtype, base);
     }
     // negative scales follows using sub.
@@ -513,7 +517,7 @@ class SumExprNode : public CanonicalExprNode {
         res = res - args[i]->NormalizeWithScale(-1);
       }
     }
-    if (base < 0) {
+    if (base < 0 && !is_min_value) {
       res = res - make_const(dtype, -base);
     }
     return res;

tests/python/unittest/test_arith_canonical_simplify.py

@@ -375,9 +375,9 @@ def test_simplify_cast():
 def test_simplify_normalize_min_value_not_error():
     ck = CanonicalChecker()
     x = te.var("x", "int32")
-    expr = te.min_value_symmetric("int32") - x == 0
+    expr = te.min_value("int32") - x == 0
     # The simplify should not error in this case.
-    ck.verify(expr, 0 - x == te.max_value("int32"))
+    ck.verify(expr, x == te.min_value("int32"))
 
 
 if __name__ == "__main__":