[Bug bootstrap/83396] [8 Regression] Bootstrap failures with Statement Frontiers

["aoliva at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83396

--- Comment #61 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 42885
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42885&action=edit
expand labels before markers

This patch fixes both ia64 problems.  Basically, the ebb scheduler gets
thoroughly confused by insns (even debug insns) outside BBs.  There's no good
reason for markers to be placed before RTL labels (or even gimple labels, but I
won't delay the fix further while I work on that), and although I can't say I
really meant to have them there, the little I did is proven to be not enough
and a lot of complication for no good reason, so...  I'll make sure we keep
debug insns (and stmts) within normal BB boundaries, and review the few changes
added to support that so as to revert them, if I can still identify them.

I haven't yet tested that we don't otherwise get debug insns outside BBs, aside
from successful compilation of the two ia64 preprocessed cases, so the cfgrtl.c
chunk may have to go for now to enable bootstraps to complete.  Please let me
know if you bootstrap with it and it passes; and if it fails, please keep the
preprocessed testcases coming my way ;-)  Thanks!