Log information about suppressed data dependent errors (#151041)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/151041
Approved by: https://github.com/bobrenjc93
ghstack dependencies: #151023, #151038

torch/fx/experimental/symbolic_shapes.py

@@ -1187,6 +1187,17 @@ def compute_unbacked_bindings(
     return symbol_to_path
 
 
+def _log_suppressed_dde(a: SymBool, assumed_value: bool) -> None:
+    sloc, extra = a.node.shape_env._get_stack_summary(True)
+    log.info(
+        "could not evaluate %s due to data dependency, it was assumed to be %s with no runtime assertions %s %s",
+        a,
+        assumed_value,
+        sloc,
+        extra,
+    )
+
+
 # The following two functions are common utilities used while defining unbacked semantics
 # of various framework 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
@@ -1210,6 +1221,7 @@ def guard_or_false(a: BoolLikeType) -> bool:
             try:
                 return guard_bool(a)
             except GuardOnDataDependentSymNode:
+                _log_suppressed_dde(a, False)
                 return False
 
 
@@ -1231,6 +1243,7 @@ def guard_or_true(a: BoolLikeType) -> bool:
             try:
                 return guard_bool(a)
             except GuardOnDataDependentSymNode:
+                _log_suppressed_dde(a, True)
                 return True