On Sep 13, 2012, at 9:51 AM, Robert Dewar <de...@adacore.com> wrote: > I routinely debugged code at -O1, but then the > compiler got better at optimization, and things deteriorated so much > at -O1 that now I don't even attempt it.
An example of a non-feature for me would be the reordering of instructions by scheduling when there is no benefit, only reorder, if there is a non-zero benefit. This causes the jumpy debug experience, and needlessly so in some cases. This is also an example that gdb can't fix. The fix would be to compute costs as tuple and have the second part of the cost be the original instruction ordering. Then, the scheduler actively works to preserve order, unless the upper case of the cost indicates there is a win to be had.
