[PATCH] D46278: [AArch64] Fold B = csel A, A into B = COPY A

[Francis Visoiu Mistrih via Phabricator via llvm-commits]

thegameg added a comment.

In https://reviews.llvm.org/D46278#1083284, @efriedma wrote:

> Do you have any idea why this is happening?  I would expect that normally, instruction selection won't insert a useless csel.  (If we're missing some fold before isel, fixing that could have a larger benefit overall.)


>From what I've seen after ISel there are no useless csel, but they are added by the EarlyIfConverter and after some coalescing and other optimizations like CSE, we end up with some useless ones. I didn't look at the EarlyIfConverter as I thought this would catch more cases.


https://reviews.llvm.org/D46278