[PATCH] D29092: PR31729: [GVNHoist] Don't hoist unsafe scalars at -Oz

[Mehdi AMINI via Phabricator via llvm-commits]

mehdi_amini added a comment.

So it seems that GVN-hoist tries to be "smarter" and hoist things for which `isSafeToSpeculativelyExecute` is returning false.
This is a nice aggressive optimization, but if it isn't safe (it seems it is not right now considering there are bugs in 4.0), we should *disable* this behavior in clang-4.0 and GVN-hoist should rely *only* on `isSafeToSpeculativelyExecute` as a legality criteria.


https://reviews.llvm.org/D29092