pytorch - 💡(How to fix) Fix INTERNAL ASSERT FAILED: NYI SymInt equality in c10/core/Scalar.h when using torch.compile(dynamic=True) and torch.autograd.grad with torch.pow

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Error Message

import torch import traceback

print("torch", torch.version) torch._dynamo.config.suppress_errors = False

def fn(x, exponent): y = torch.pow(x, exponent) loss = y.sum() grad, = torch.autograd.grad(loss, x) return y, grad

x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True) exponent = 0

print("\n=== eager ===") y, g = fn(x, exponent) print("y:", y) print("grad:", g)

for backend in ["aot_eager", "inductor"]: print(f"\n=== torch.compile backend={backend}, dynamic=True ===") compiled_fn = torch.compile(fn, backend=backend, dynamic=True)

x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True)

try:
    y, g = compiled_fn(x, exponent)
    print("y:", y)
    print("grad:", g)
except Exception:
    traceback.print_exc()

Code Example

import torch
import traceback

print("torch", torch.__version__)
torch._dynamo.config.suppress_errors = False

def fn(x, exponent):
    y = torch.pow(x, exponent)
    loss = y.sum()
    grad, = torch.autograd.grad(loss, x)
    return y, grad

x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True)
exponent = 0  

print("\n=== eager ===")
y, g = fn(x, exponent)
print("y:", y)
print("grad:", g)

for backend in ["aot_eager", "inductor"]:
    print(f"\n=== torch.compile backend={backend}, dynamic=True ===")
    compiled_fn = torch.compile(fn, backend=backend, dynamic=True)

    x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True)

    try:
        y, g = compiled_fn(x, exponent)
        print("y:", y)
        print("grad:", g)
    except Exception:
        traceback.print_exc()
RAW_BUFFERClick to expand / collapse

🐛 Describe the bug

When compiling a function using torch.compile with dynamic=True and taking gradients via torch.autograd.grad after a torch.pow operation, it throws an internal assert error in the C++ engine: false INTERNAL ASSERT FAILED at "/__w/pytorch/pytorch/c10/core/Scalar.h":273, please report a bug to PyTorch. NYI SymInt equality.

This occurs on both aot_eager and inductor backends. And maybe the issue only reproduces when the exponent is passed as a Python int argument. If the exponent is written as a literal constant inside the function, e.g. torch.pow(x, 0), the issue does not reproduce.

Reproduction Script

import torch
import traceback

print("torch", torch.__version__)
torch._dynamo.config.suppress_errors = False

def fn(x, exponent):
    y = torch.pow(x, exponent)
    loss = y.sum()
    grad, = torch.autograd.grad(loss, x)
    return y, grad

x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True)
exponent = 0  

print("\n=== eager ===")
y, g = fn(x, exponent)
print("y:", y)
print("grad:", g)

for backend in ["aot_eager", "inductor"]:
    print(f"\n=== torch.compile backend={backend}, dynamic=True ===")
    compiled_fn = torch.compile(fn, backend=backend, dynamic=True)

    x = torch.ones((1, 3), device="cuda", dtype=torch.bfloat16, requires_grad=True)

    try:
        y, g = compiled_fn(x, exponent)
        print("y:", y)
        print("grad:", g)
    except Exception:
        traceback.print_exc()

Error log

errorlog.txt

Versions

PyTorch version: 2.13.0.dev20260521+cu130 Is debug build: False CUDA used to build PyTorch: 13.0 ROCM used to build PyTorch: N/A

OS: Ubuntu 24.04.4 LTS (x86_64) GCC version: (Ubuntu 13.3.0-6ubuntu2~24.04.1) 13.3.0 Clang version: 18.1.3 (1ubuntu1) CMake version: version 3.28.3 Libc version: glibc-2.39

Python version: 3.10.20 (main, Mar 11 2026, 17:46:40) [GCC 14.3.0] (64-bit runtime) Python platform: Linux-5.15.167.4-microsoft-standard-WSL2-x86_64-with-glibc2.39 Is CUDA available: True CUDA runtime version: 12.0.140 Nvidia driver version: 596.49 cuDNN version: Probably one of the following: /usr/lib/x86_64-linux-gnu/libcudnn.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_adv.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_cnn.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_engines_precompiled.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_engines_runtime_compiled.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_engines_tensor_ir.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_graph.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_heuristic.so.9.21.1 /usr/lib/x86_64-linux-gnu/libcudnn_ops.so.9.21.1 Is XPU available: False HIP runtime version: N/A MIOpen runtime version: N/A Is XNNPACK available: True Caching allocator config: N/A ersions of relevant libraries: [pip3] numpy==2.2.6 [pip3] nvidia-cublas==13.1.1.3 [pip3] nvidia-cuda-cupti==13.0.85 [pip3] nvidia-cuda-nvrtc==13.0.88 [pip3] nvidia-cuda-runtime==13.0.96 [pip3] nvidia-cudnn-cu13==9.20.0.48 [pip3] nvidia-cufft==12.0.0.61 [pip3] nvidia-curand==10.4.0.35 [pip3] nvidia-cusolver==12.0.4.66 [pip3] nvidia-cusparse==12.6.3.3 [pip3] nvidia-cusparselt-cu13==0.8.1 [pip3] nvidia-nccl-cu13==2.29.7 [pip3] nvidia-nvjitlink==13.0.88 [pip3] nvidia-nvtx==13.0.85 [pip3] torch==2.13.0.dev20260521+cu130 [pip3] torchaudio==2.11.0.dev20260525+cu130 [pip3] torchvision==0.28.0.dev20260525+cu130 [pip3] triton==3.7.0+git88b227e2 [conda] numpy 2.2.6 pypi_0 pypi [conda] nvidia-cublas 13.1.1.3 pypi_0 pypi [conda] nvidia-cuda-cupti 13.0.85 pypi_0 pypi [conda] nvidia-cuda-nvrtc 13.0.88 pypi_0 pypi [conda] nvidia-cuda-runtime 13.0.96 pypi_0 pypi [conda] nvidia-cudnn-cu13 9.20.0.48 pypi_0 pypi [conda] nvidia-cufft 12.0.0.61 pypi_0 pypi [conda] nvidia-curand 10.4.0.35 pypi_0 pypi [conda] nvidia-cusolver 12.0.4.66 pypi_0 pypi [conda] nvidia-cusparse 12.6.3.3 pypi_0 pypi [conda] nvidia-cusparselt-cu13 0.8.1 pypi_0 pypi [conda] nvidia-nccl-cu13 2.29.7 pypi_0 pypi [conda] nvidia-nvjitlink 13.0.88 pypi_0 pypi [conda] nvidia-nvtx 13.0.85 pypi_0 pypi [conda] torch 2.13.0.dev20260521+cu130 pypi_0 pypi [conda] torchaudio 2.11.0.dev20260525+cu130 pypi_0 pypi [conda] torchvision 0.28.0.dev20260525+cu130 pypi_0 pypi [conda] triton 3.7.0+git88b227e2 pypi_0 pypi

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pytorch - 💡(How to fix) Fix INTERNAL ASSERT FAILED: NYI SymInt equality in c10/core/Scalar.h when using torch.compile(dynamic=True) and torch.autograd.grad with torch.pow