[CPU] Use MayInPlace kernel def hint for FusedConv kernel - #26422
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Hariharan Seshadri (hariharans29)
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Pull Request Overview
This PR adds a memory optimization hint to the CPU FusedConv operator by enabling in-place operation between the optional "sum" input (Z) and the output buffer.
- Adds
.MayInplace(3, 0)hint to the FusedConv kernel definition for the CPU execution provider
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Tianlei Wu (tianleiwu)
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Oct 28, 2025
Naomi Ovadia (naomiOvad)
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Nov 2, 2025
…26422) ### Description Use MayInPlace hint for the FusedConv NCHW CPU kernel that allows for the allocation planner to re-use the optional "sum" input buffer as the kernel's output buffer. It will potentially save [this copy](https://github.com/microsoft/onnxruntime/blob/06004826cc99dd8b8b92dbf000db3d3525716f22/onnxruntime/core/providers/cpu/nn/conv.cc#L209) if the buffers can be shared (in most cases the buffers can be shared) ### Motivation and Context The kernel already had logic to save the copy but the kernel def was missing the hint to the allocation planner. Found while investigating improvements to a Conv model's performance on ARM64
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Description
Use MayInPlace hint for the FusedConv NCHW CPU kernel that allows for the allocation planner to re-use the optional "sum" input buffer as the kernel's output buffer. It will potentially save this copy if the buffers can be shared (in most cases the buffers can be shared)
Motivation and Context
The kernel already had logic to save the copy but the kernel def was missing the hint to the allocation planner.
Found while investigating improvements to a Conv model's performance on ARM64