[PATCH] D24956: [SelectionDAG] Add expansion and promotion of [US]MUL_LOHI

[James Y Knight via llvm-commits]

jyknight added a comment.

I don't really understand why this needs to be a new target hook. Can't it have similar code as the MUL expansion code at LegalizeDAG.cpp:3316 (in the base version): if MULH and MUL are LegalOrCustom, then you'd split the MUL_LOHI into those two operations. Otherwise, you'd do half-width multiplies?

Also, I've fixed the sparc backend to properly implement [US]MUL_LOHI in r283381, removing the FIXME here.


https://reviews.llvm.org/D24956