llvm-project

626cbf70 - [X86] isGuaranteedNotToBeUndefOrPoison - add simple target shuffles with known test coverage (#161553)

[X86] isGuaranteedNotToBeUndefOrPoison - add simple target shuffles with known test coverage (#161553) Add a number of simple target shuffles (fixed shuffle mask or simple immediate control) to isGuaranteedNotToBeUndefOrPoison/canCreateUndefOrPoisonForTargetNode that have known test coverage and obviously don't introduce undef/poison. These were found by adding an assert for unhandled target shuffles and running over CodeGen/X86 - providing explicit test coverage is incredibly difficult as ISD::VECTOR_SHUFFLE nodes will typically handle freeze nodes before we lower to these target shuffle nodes.