[Diffusion] rG13ec913bdf50: [InstCombine] Recognize `((x * y) s/ x) !=/== y` as an signed multiplication…

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In rG13ec913bdf500e2354cc55bf29e2f5d99e0c709e#990855 <https://reviews.llvm.org/rG13ec913bdf500e2354cc55bf29e2f5d99e0c709e#990855>, @RKSimon wrote:

> Isn't the problem the limited lowering options in TargetLowering::expandMULO ? If we fell back to reusing the expansions we have in TargetLowering::expandMUL_LOHI then we'd probably be OK ?

I did just look at that, and indeed, we always custom lower SMULO into a libcall.
This doesn't seem optimal.


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https://reviews.llvm.org/rG13ec913bdf50