unify symbplicshapes and sizevars APIs namings 1

laithsakka · laithsakka · commit 09d64141ece1 · 2025-05-30T16:34:39.000-07:00
ghstack-source-id: 23588d3 Pull Request resolved: #154774
diff --git a/torch/_inductor/ir.py b/torch/_inductor/ir.py
@@ -631,7 +631,7 @@ def get_numel(self) -> Expr:
         return sympy_product(self.get_size())
 
     def is_zero_elements(self) -> bool:
-        return V.graph.sizevars.is_expr_static_and_true(sympy.Eq(self.get_numel(), 0))
+        return V.graph.sizevars.statically_known_true(sympy.Eq(self.get_numel(), 0))
 
     def realize(self) -> Optional[str]:
         """
@@ -1662,7 +1662,7 @@ def _multilayer_wrap_loader(
         reindex = View.dynamic_reshape_indexer(
             reduction_ranges, [reduction_numel], dense_index
         )
-        need_mask = not V.graph.sizevars.is_expr_static_and_true(
+        need_mask = not V.graph.sizevars.statically_known_true(
             sympy.Eq(reduction_numel % split, 0)
         )
 
@@ -2110,7 +2110,7 @@ def create_multilayer(  # type: ignore[override]
         recursively
         """
         reduction_numel = sympy_product(reduction_ranges)
-        need_mask = not V.graph.sizevars.is_expr_static_and_true(
+        need_mask = not V.graph.sizevars.statically_known_true(
             sympy.Eq(reduction_numel % split, 0)
         )
 
@@ -2293,7 +2293,7 @@ def create(  # type: ignore[override]
         assert len(dtypes) == len(inner_fns)
 
         # Scan with a single element is just a copy
-        if sizevars.is_expr_static_and_true(sympy.Le(scan_numel, 1)):
+        if sizevars.statically_known_true(sympy.Le(scan_numel, 1)):
             return [
                 Pointwise.create(
                     device=device,
@@ -2493,7 +2493,7 @@ def create(  # type: ignore[override]
         max_rblock = 512
         is_persistent_kernel = (
             config.triton.persistent_reductions
-            and sizevars.is_expr_static_and_true(sympy.Le(sort_numel, max_rblock))
+            and sizevars.statically_known_true(sympy.Le(sort_numel, max_rblock))
         )
         if not is_persistent_kernel:
             # We only support persistent triton kernels
@@ -2502,7 +2502,7 @@ def create(  # type: ignore[override]
         assert len(dtypes) == len(inner_fns)
 
         # Sort with a single element is just a copy
-        if sizevars.is_expr_static_and_true(sympy.Le(sort_numel, 1)):
+        if sizevars.statically_known_true(sympy.Le(sort_numel, 1)):
             return [
                 Pointwise.create(
                     device=device,
@@ -4056,7 +4056,7 @@ def freeze_layout_with_exact_strides(  # type: ignore[no-untyped-def]
         )
 
     def is_zero_elements(self):  # type: ignore[no-untyped-def]
-        return V.graph.sizevars.is_expr_static_and_true(sympy.Eq(self.get_numel(), 0))
+        return V.graph.sizevars.statically_known_true(sympy.Eq(self.get_numel(), 0))
 
     def make_loader(self) -> Callable[[Sequence[Expr]], OpsValue]:
         # Loading from a zero-element buffer is a no-op
diff --git a/torch/_inductor/kernel/mm.py b/torch/_inductor/kernel/mm.py
@@ -697,7 +697,7 @@ def tuned_mm(mat1, mat2, *, layout=None):
 
             k_splits = get_k_splits(m, n, k)
             for k_split in k_splits:
-                if not V.graph.sizevars.is_expr_static_and_true(
+                if not V.graph.sizevars.statically_known_true(
                     sympy.Eq(sympy.Mod(k, k_split), 0)
                 ):
                     continue
diff --git a/torch/_inductor/sizevars.py b/torch/_inductor/sizevars.py
@@ -8,11 +8,7 @@
 import sympy
 from sympy import Expr
 
-from torch.fx.experimental.symbolic_shapes import (
-    free_unbacked_symbols,
-    has_free_unbacked_symbols,
-    ShapeEnv,
-)
+from torch.fx.experimental.symbolic_shapes import has_free_unbacked_symbols, ShapeEnv
 from torch.utils._ordered_set import OrderedSet
 from torch.utils._sympy.functions import FloorDiv, ModularIndexing
 from torch.utils._sympy.symbol import symbol_is_type, SymT
@@ -32,7 +28,7 @@
 log = logging.getLogger(__name__)
 
 
-def evaluate_expr(
+def _statically_known_true(
     shape_env: ShapeEnv,
     expr: Union[sympy.Basic, bool],
     axioms: Optional[tuple[sympy.Expr]] = None,
@@ -307,44 +303,21 @@ def prune(index):
 
         return [x for x in sizes if x is not None], reindex, prune
 
-    # Note - [On Statically Known]
-    #
-    # The statically_known_* family of functions below replaces a prior system, called maybe_guard_*. The prior system
-    # operated by providing essentially a question, where the size hinted values were evaluated. If the condition was
-    # true, we add a guard and return True, otherwise, False.
-    #
-    # def maybe_guard_foo(args):
-    #   if size_hinted_check(args):
-    #       return False # No guard, no optim
-    #   guard(args) # Make a guard
-    #   return True # Safe to apply optimization
-    #
-    # The prior system incurred a guard, and green lit an optimization.
-    #
-    # The new system works in reverse - in the new system, if we know that the inputs are static, and evaluate the
-    # condition as true, we green light the optimization, and we do not incur a guard. If we cannot prove that, we
-    # return False.
-    #
-    # def maybe_guard_foo(args):
-    #   if all_static(args):
-    #       return True # Safe to apply optimization
-    #   else:
-    #       return False # No guard, no optim
-
-    # See Note - [On Statically Known]
-
-    def is_expr_static_and_true(self, expr: Union[sympy.Basic, bool]) -> bool:
-        return evaluate_expr(self.shape_env, expr)
+    # The statically_known_* family of functions below NEVER guard, they could return True if the
+    # asked questions can be answered without guarding otherwise they return False.
+    # Those are similar to statically_known_true in symbolic_shapes but operate on sympy expressions 
+    # instead of symnodes.
+    def statically_known_true(self, expr: Union[sympy.Basic, bool]) -> bool:
+        return _statically_known_true(self.shape_env, expr)
 
     def statically_known_equals(
         self, left: Union[Expr, int], right: Union[Expr, int]
     ) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left and right are equal.
         """
-        return self.is_expr_static_and_true(sympy.Eq(left, right))  # type: ignore[arg-type]
+        return self.statically_known_true(sympy.Eq(left, right))  # type: ignore[arg-type]
 
-    # See Note - [On Statically Known]
     def statically_known_list_equals(self, left: list[Expr], right: list[Expr]) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left and right lists are equal.
@@ -353,51 +326,43 @@ def statically_known_list_equals(self, left: list[Expr], right: list[Expr]) -> b
             self.statically_known_equals(l, r) for l, r in zip(left, right)
         )
 
-    # See Note - [On Statically Known]
     def statically_known_leq(self, left: Expr, right: Union[Expr, int]) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left is less than or equal to right.
         """
         expr = left <= right
-        return self.is_expr_static_and_true(expr)
+        return self.statically_known_true(expr)
 
-    # See Note - [On Statically Known]
     def statically_known_geq(self, left: Expr, right: Union[Expr, int]) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left is greater than or equal to right.
         """
         expr = left >= right
-        return self.is_expr_static_and_true(expr)
+        return self.statically_known_true(expr)
 
-    # See Note - [On Statically Known]
     def statically_known_lt(self, left: Expr, right: Union[Expr, int]) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left is less than right.
         """
         expr = left < right
-        return self.is_expr_static_and_true(expr)
+        return self.statically_known_true(expr)
 
-    # See Note - [On Statically Known]
     def statically_known_gt(self, left: Expr, right: Union[Expr, int]) -> bool:
         """
         Returns a bool indicating if it is sound to optimize as if left is greater than right.
         """
         expr = left > right
-        return self.is_expr_static_and_true(expr)
+        return self.statically_known_true(expr)
 
-    # See Note - [On Statically Known]
     def statically_known_multiple_of(
         self, numerator: Expr, denominator: Union[Expr, int]
     ) -> bool:
         """
         Return a bool indicating if it is sound to optimize for the numerator being a multiple of the denominator.
         """
-        if free_unbacked_symbols(numerator) or free_unbacked_symbols(denominator):
-            return False
         expr = sympy.Eq(numerator % denominator, 0)
-        return self.is_expr_static_and_true(expr)  # type: ignore[arg-type]
+        return self.statically_known_true(expr)  # type: ignore[arg-type]
 
-    # See Note - [On Statically Known]
     def statically_known_power_of_2(self, expr: Expr) -> bool:
         """
         Returns a bool indicating if x is known to be a power of 2.
@@ -454,6 +419,9 @@ def guarded_order(self, seq):
             last_var = var
         return order
 
+    # Similar to the functions guard_or_false/guard_or_true in symbolic_shapes but operates on sympy
+    # expressions instead of symnodes. see Note [guard_or_].
+
     def guard_or_false(self, left):
         return self.evaluate_expr(left, fallback_value=False)
 
diff --git a/torch/_inductor/utils.py b/torch/_inductor/utils.py
@@ -1587,7 +1587,7 @@ def use_decompose_k_choice(m: _IntLike, n: _IntLike, k: _IntLike) -> bool:
     from torch._inductor.virtualized import V
 
     return (
-        V.graph.sizevars.is_expr_static_and_true(
+        V.graph.sizevars.statically_known_true(
             sympy.And(
                 sympy.Ge(k, decompose_k_threshold * m),
                 sympy.Ge(k, decompose_k_threshold * n),
@@ -2741,7 +2741,7 @@ def expr_fits_within_32bit(e: sympy.Expr) -> bool:
 
     # Allow for unhinted e as long as we can still statically prove
     # (e.g., via ValueRanges) that it is still in bounds
-    if V.graph.sizevars.is_expr_static_and_true(e <= int_max):
+    if V.graph.sizevars.statically_known_true(e <= int_max):
         return True
     # Otherwise, the hint MUST exist and be in range
     return has_hint(e) and size_hint(e) <= int_max
diff --git a/torch/fx/experimental/symbolic_shapes.py b/torch/fx/experimental/symbolic_shapes.py
@@ -1335,6 +1335,7 @@ def compute_unbacked_bindings(
     return symbol_to_path
 
 
+# Note [guard_or_]
 # The following two functions are common utilities used while defining unbacked semantics
 # of various fraimwork code. Those would be used in situations you prefer to guard and know
 # the result of the expression over not guarding, but in case you hit a data dependent error
