[PATCH] D88391: [M68k] (Patch 5/8) Target lowering

[Renato Golin via Phabricator via llvm-commits]

rengolin added a comment.

In D88391#2441942 <https://reviews.llvm.org/D88391#2441942>, @zixuan-wu wrote:

> Hmm, I am just curious about that whether GlobalISEL is mature enough to use as default instruction selection method without implementing SelectionDAG. As a newer backend, I really would like to drop legacy stuff at start if it works.

Unfortunately, no. Even if GIsel is mature enough for some codegen (ex. O0 on AArch64), it isn't mature across the board to make SelDAG "legacy" yet.

Waiting for that to happen for your target would be counter productive, especially in an experimental state.

>From what I hear, this target is mature enough (using SelDAG) to compile real world applications including possibly Linux.

Replacing SelGDAG with GIsel isn't trivial even if it was mature enough. But as an experimental target, you'll have a lot of other issues to deal with until it moves to production.

So, for now, I'd stick with SelDAG and land the target as is.


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