From c93e34d7b5690ee77cd29dc7b28a8aa7f61d58aa Mon Sep 17 00:00:00 2001
From: PyTorch MergeBot <pytorchmergebot@users.noreply.github.com>
Date: Fri, 4 Apr 2025 16:26:00 +0000
Subject: [PATCH] Revert "bound sympy accuracy (#150383)"

This reverts commit 1bc2b2b12ae1ddd27b0401a1baac3b8099b6fc50.

Reverted https://github.com/pytorch/pytorch/pull/150383 on behalf of https://github.com/laithsakka due to big regression ([comment](https://github.com/pytorch/pytorch/pull/150383#issuecomment-2779227548))
---
 test/export/test_export.py         | 22 ----------------------
 torch/utils/_sympy/value_ranges.py | 17 -----------------
 2 files changed, 39 deletions(-)

diff --git a/test/export/test_export.py b/test/export/test_export.py
index 5eefb67c14b..988e2fae81c 100755
--- a/test/export/test_export.py
+++ b/test/export/test_export.py
@@ -3105,28 +3105,6 @@ def forward(self, p_linear_weight, p_linear_bias, x):
                 "dy - 6 = 6" not in exc.args[0]
             )  # don't suggest fix for non-root dim
 
-    @testing.expectedFailureLegacyExportNonStrict  # FIXME constraint violation (guard: s0 - s0%8 != 1)
-    @testing.expectedFailureCppSerDes  # FIXME data-dependent error (hinted: True, unhinted: s0 - s0%8 >= 0)
-    def test_bound_sympy_accuracy(self):
-        class Foo(torch.nn.Module):
-            def forward(self, x):
-                expr = x.shape[0] - (x.shape[0] % 8)
-                return torch.empty(expr)
-
-        ep = export(
-            Foo(),
-            (torch.randn(13),),
-            dynamic_shapes={"x": (Dim("dim", min=2),)},
-        )
-
-        (output,) = ep.graph.output_node().args[0]
-        sym_node = output.meta["val"].shape[0].node
-        vr = torch.utils._sympy.value_ranges.bound_sympy(
-            sym_node.expr,
-            sym_node.shape_env.var_to_range,
-        )
-        self.assertEqual(vr.lower, 0)
-
     @unittest.skip("See https://github.com/pytorch/pytorch/issues/135759")
     def test_keep_composite_ops_invalid(self):
         class Foo(torch.nn.Module):
diff --git a/torch/utils/_sympy/value_ranges.py b/torch/utils/_sympy/value_ranges.py
index 118959b8c4d..784f9e7ba05 100644
--- a/torch/utils/_sympy/value_ranges.py
+++ b/torch/utils/_sympy/value_ranges.py
@@ -1004,22 +1004,6 @@ class SymPyValueRangeAnalysis:
         return ValueRanges.increasing_map(x, TruncToFloat)
 
 
-def _rewrite_for_value_range_analysis(expr: sympy.Expr):
-    """
-    Sometimes accuracy of value range analysis can be improved
-    with simple rewriting rules.
-    """
-
-    # Rewrite X - X%Y to (X//Y) * Y.
-    x, y = sympy.Wild("x"), sympy.Wild("y")
-    expr = expr.replace(
-        x - torch.utils._sympy.functions.Mod(x, y),
-        torch.utils._sympy.functions.FloorDiv(x, y) * y,
-    )
-
-    return expr
-
-
 def bound_sympy(
     expr: sympy.Expr, ranges: Optional[dict[sympy.Symbol, ValueRanges]] = None
 ) -> ValueRanges:
@@ -1063,7 +1047,6 @@ def bound_sympy(
             vr = ValueRanges.unknown()
         return vr
 
-    expr = _rewrite_for_value_range_analysis(expr)
     return sympy_interp(
         SymPyValueRangeAnalysis, ranges, expr, missing_handler=missing_handler
     )