[PATCH] D50310: Improve the legalisation lowering of UMULO

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> The computation of %LHS.HI * %RHS.HI is only necessary to compute the overflow bit.

Oh, sorry, you're right, not sure what I was thinking.

I was reading the AArch64 code and thinking it looked strange, but the issue was just that the code was doing the operations in a strange order.  An i128 multiply normally generates umulh+madd+madd, but for some reason your expansion generates mul+umulh+madd+add.  Not really important.


https://reviews.llvm.org/D50310