Ayonam Ray <ayonam@xxxxxxxxx> writes: > My architecture has a hardware loop implementation which works only if > there are no conditional branches in the loop body. We have > implemented the doloop_begin and doloop_end RTLs and also the target > macro TARGET_INVALID_WITHIN_DOLOOP. > > The optimization works correctly except that in some cases the basic > block reordering pass (and possibly some other passes) reorder the > blocks in such a manner that the body of the loop no longer remains as > a single basic block or even successive basic blocks that fall through > to the next, even though the original code has no branches within the > loop body. > > This makes the final code generation impossible since the doloop > specific instructions can no longer be generated. > > Any suggestions at preventing the basic block reordering happening for > such loops? We tried turning off the basic block reorder pass but > then some other pass appears to still mess it up. If you don't have any branches in the loop body then I'm not sure why you get multiple basic blocks. I don't know of any easy way to prevent the compiler from rearranging basic blocks. Ian
