From b87d3ddd0d991eaf1a47b714aa66536834bc9c2c Mon Sep 17 00:00:00 2001
From: Laith Sakka <lsakka@meta.com>
Date: Sun, 19 Oct 2025 17:27:06 -0700
Subject: [PATCH] Update base for Update on "[WIP] Support python slicing with
 tensor inputs."
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

allow things like
```
#!/usr/bin/env python
import torch

print("="*60)
print("Testing tensor slicing with torch.compile")
print("="*60)

# Test 1: Simple eager mode
print("\n1. Eager mode test:")
x = torch.randn(10)
idx = torch.tensor(4)
result = x[:idx]
print(f"   x[:idx] where idx=4: result.shape = {result.shape}")
assert result.shape[0] == 4
print("   ✓ Eager mode works!")

# Test 2: With torch.compile
print("\n2. Compiled mode test:")
def slice_fn(x, idx):
    return x[:idx]

try:
    compiled_fn = torch.compile(slice_fn)
    x = torch.randn(10)
    idx = torch.tensor(4)
    result = compiled_fn(x, idx)
    print(f"   Compiled x[:idx] where idx=4: result.shape = {result.shape}")
    assert result.shape[0] == 4
    print("   ✓ Compiled mode works!")
except Exception as e:
    print(f"   ✗ Compiled mode failed: {e}")
    import traceback
    traceback.print_exc()

# Test 3: With dynamic slicing from sum
print("\n3. Dynamic slicing with sum:")
def dynamic_slice_fn(x, lengths):
    idx = lengths.sum()
    return x[:idx]

try:
    compiled_fn = torch.compile(dynamic_slice_fn)
    x = torch.randn(10)
    lengths = torch.tensor([1, 1, 1, 1])
    result = compiled_fn(x, lengths)
    print(f"   Compiled x[:lengths.sum()] where sum=4: result.shape = {result.shape}")
    assert result.shape[0] == 4
    print("   ✓ Dynamic slicing works!")
except Exception as e:
    print(f"   ✗ Dynamic slicing failed: {e}")
    import traceback
    traceback.print_exc()

print("\n" + "="*60)
print("SUMMARY: Check results above")
print("="*60)

```


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

[ghstack-poisoned]