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Are there other intrinsics like _mm_maskmoveu_si128 that require mutable memory even when no mutation occurs? #2216
Description
As documented in #2196, _mm_maskmoveu_si128(a, mask, ptr) requires the memory ptr points to to be writable, even if the mask makes it so that no write actually occurs.
Are there any other intrinsics like that? They should all get corresponding remarks in their documentation.
Cc @programmerjake @Amanieu @workingjubilee @folkertdev
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programmerjake commentedon Aug 31, 2026
the only other x86 instructions I'm aware of that behaves like this are
cmpxchg, and the double-sized versioncmpxchg8b/cmpxchg16b.There may be additional instructions I'm not aware of though.