[PATCH] D123602: [MSan] Ensure argument shadow initialized on memcpy

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

In D123602#3445885 <https://reviews.llvm.org/D123602#3445885>, @vitalybuka wrote:

> I am not sure how this can help, I will try later today.
> As I see it it just calculates the shadow address and these instructions will be removed as unused?

Shadow memory for arguments is lazily initialized. If we never call getShadow() for an argument, then we'll leave it uninitialized. In most cases this happens naturally, but for memcpy/memmove we call a builtin that will access the shadow internally, so we never perform the getShadow() call and never initialize the shadow.


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https://reviews.llvm.org/D123602