[ghstack-poisoned]

### What
- Use `statically_known_true` over `guard_size_oblivious` in cases where we're checking an optimization path. Otherwise, it will DDE and we can't take the safe/slower path.
- For broadcast checks, use fallback=False if we encounter a DDE. Typically, unbackeds would be ≥2 and that falls inline with size-oblivious reasoning.
- In `coerce_tangent_and_suggest_memory_format`, use the torch._refs version of `contiguous` over Aten's version because Aten doesn't have a DDE-friendly path (yet).

### Example DDE
```
GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq(128*((u0//387)), 0) (unhinted: Eq(128*((u0//387)), 0)).  (Size-like symbols: u0)

Caused by: (_functorch/_aot_autograd/collect_metadata_analysis.py:84 in coerce_tangent_and_suggest_memory_format)
```

```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/lowering.py:488 in broadcast_symbolic_shapes)
```
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/ir.py:2797 in create)
```




cc voznesenskym penguinwu EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]

### What
- Use `statically_known_true` over `guard_size_oblivious` in cases where we're checking an optimization path. Otherwise, it will DDE and we can't take the safe/slower path.
- For broadcast checks, use fallback=False if we encounter a DDE. Typically, unbackeds would be ≥2 and that falls inline with size-oblivious reasoning.
- In `coerce_tangent_and_suggest_memory_format`, use the torch._refs version of `contiguous` over Aten's version because Aten doesn't have a DDE-friendly path (yet).

### Example DDE
```
GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq(128*((u0//387)), 0) (unhinted: Eq(128*((u0//387)), 0)).  (Size-like symbols: u0)

Caused by: (_functorch/_aot_autograd/collect_metadata_analysis.py:84 in coerce_tangent_and_suggest_memory_format)
```

```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/lowering.py:488 in broadcast_symbolic_shapes)
```
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/ir.py:2797 in create)
```




cc voznesenskym penguinwu EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]

### What
- Use `statically_known_true` over `guard_size_oblivious` in cases where we're checking an optimization path. Otherwise, it will DDE and we can't take the safe/slower path.
- For broadcast checks, use fallback=False if we encounter a DDE. Typically, unbackeds would be ≥2 and that falls inline with size-oblivious reasoning.

### Example DDE
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/lowering.py:488 in broadcast_symbolic_shapes)
```
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/ir.py:2797 in create)
```




cc voznesenskym penguinwu EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]

### What
- Use `statically_known_true` over `guard_size_oblivious` in cases where we're checking an optimization path. Otherwise, it will DDE and we can't take the safe/slower path.
- For broadcast checks, use `fallback=False` if we encounter a DDE. Typically, unbackeds would be ≥2 and that falls inline with size-oblivious reasoning (i.e. when `size_oblivious=True`).

### Example DDE
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/lowering.py:488 in broadcast_symbolic_shapes)
```
```
torch._inductor.exc.InductorError: LoweringException: GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq((u0//387), 1) (unhinted: Eq((u0//387), 1)).  (Size-like symbols: u0)

Caused by: (_inductor/ir.py:2797 in create)
```




cc ezyang penguinwu bobrenjc93 voznesenskym EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov coconutruben

[ghstack-poisoned]