[llvm] [InstCombineCompare] Use known bits to insert assume intrinsics. (PR #96017)

[Mikhail Gudim via llvm-commits]

mgudim wrote:

> > What if I add a flag to explicitly enable this and have this disabled by default?
> 
> Do you mean `--enable-knowledge-retention`?

Oh, I didn't know about this flag. I thought that the extra code to compute the argument to "assume" prevents the optimizations, Is this true? Will this flag help?

https://github.com/llvm/llvm-project/pull/96017