Tail merge was making the assumption that a layout successor or
predecessor was always a cfg successor/predecessor. Remove that
assumption. Changes to tests are necessary because the errant cfg edges
were preventing optimizations.
llvm-svn: 273700
Targets like SPARC and MIPS have delay slots and normally bundle the
delay slot instruction with the corresponding terminator.
Teach isBlockOnlyReachableByFallthrough to find any MBB operands on
bundled terminators so SPARC doesn't need to specialize this function.
llvm-svn: 199061