[BUG] Compile warning/error - -Werror=unused-but-set-variable unused curr_stride in cute/layout.hpp via flash attention.

[Skylion007]

Describe the bug
A clear and concise description of what the bug is.

Compile Warning with unused variable in cute layout.h with constexpr if else.

Steps/Code to reproduce bug
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Compile flash attention via CUTLASS like in PyTorch. Generates a warning relating to this line:

cutlass/include/cute/layout.hpp

Line 1070 in 5e49724

auto curr_stride = get<curr_i>(lhs_stride);

Either move the getter into the if else statement below (which make lhstride maybe unused) or add [[maybe unused]] to that accessor as well.

Full logs from the build here:

2025-04-19T03:36:32.7810494Z /var/lib/jenkins/workspace/aten/src/ATen/../../../third_party/cutlass/include/cute/layout.hpp:1066:6: error: variable ‘curr_stride’ set but not used [-Werror=unused-but-set-variable]

https://hud.pytorch.org/pr/pytorch/pytorch/151253#40809563092

Expected behavior
No compiler warning with the PyTorch build script and no crash since warnings are treated as errors here.

Environment details (please complete the following information):

• Environment location: [Bare-metal, Docker, Cloud(specify cloud provider)]

Additional context
Add any other context about the problem here.

[hwu36]

it should be fixed in 3.9