If a scalable vector uitofp or sitofp effectively extends the size of each element as part of the conversion, the AArch64 backend may need to plant multiple unpacks before converting. Increase the cost in those cases to account for this.
br i1 undef
dx.Layout
collectTransitivePredecessors
ScalarEvolution::howFarToZero
isGuaranteedNotToBeUndefOrPoison