[llvm] [SimplifyCFG] Treat umul + extract pattern as cheap single instruction. (PR #124933)

[Antonio Frighetto via llvm-commits]

=?utf-8?q?Gábor?= Spaits <gaborspaits1 at gmail.com>,
=?utf-8?q?Gábor?= Spaits <gaborspaits1 at gmail.com>,
=?utf-8?q?Gábor?= Spaits <gaborspaits1 at gmail.com>,
=?utf-8?q?Gábor?= Spaits <gaborspaits1 at gmail.com>,Gabor Spaits
 <gaborspaits1 at gmail.com>,Gabor Spaits <gaborspaits1 at gmail.com>,Gabor Spaits
 <gaborspaits1 at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/124933 at github.com>


antoniofrighetto wrote:

> @antoniofrighetto I have fixed the failing test case. It seems like we have a regression, compared to some earlier state of the PR, that has been lost to squashing. Now we get back the original state of `llvm/test/Transforms/PhaseOrdering/X86/unsigned-multiply-overflow-check.ll`. I will check why it no longer fixes that X86 test case.

Yeah, this started regressing since 838e617069e555468753bf902eb2bfdba3fe6309 (and unfortunately previous 6dade290797ae1852c8c1f816a3c856b1493dfdd seems not to be available anymore).

https://github.com/llvm/llvm-project/pull/124933