[PATCH] D70963: [cmake] Disable GCC 9's -Wredundant-move

[Pavel Labath via Phabricator via llvm-commits]

labath added a subscriber: rtrieu.
labath added a comment.

After some archaeology, this is what I've learned. Clang used to (a very long time ago) have -Wredundant-move behavior which mostly matched what the current gcc does. Then, in rL243594 <https://reviews.llvm.org/rL243594> (2015), it's scope was reduced to only cover the simple cases (no type conversion involved). It seems the reason for that was that clang at that time did not implement DR1579, and so the thing which the warning suggested to do was actually invalid. Some time later in 2016, DR1579 was implemented (rL274291 <https://reviews.llvm.org/rL274291>). However, the warning remained unchanged.

Anyway, it seems that we can leave the warning enabled for clang, at least until it doesn't become more aggressive.

+ at rtrieu (author of rL243594 <https://reviews.llvm.org/rL243594>) to see whether it's worth re-enabling that warning now.


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  https://reviews.llvm.org/D70963/new/

https://reviews.llvm.org/D70963