[PATCH] D155986: [clang][AMDGPU]: Don't use byval for struct arguments in function ABI

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D155986#4529782 <https://reviews.llvm.org/D155986#4529782>, @yaxunl wrote:

> Does this patch cause the callee to skip making a local copy of the struct type argument? What if the callee makes changes to the argument? That is a common use case since users assume the function arguments in C/C++/HIP are passed by value.

The callee is supposed to use an explicit memcpy. The explicit memcpy can be optimized away most of the time. The current byval is an invisible copy on the caller side which is difficult to eliminate


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https://reviews.llvm.org/D155986