Premature ping? Also bootstrapped&tested on ia64-unknown-linux-gnu now.
On Sun, Apr 7, 2013 at 12:40 AM, Steven Bosscher wrote: > Hello, > > In this PR43631, var-tracking notes are inserted on basic block > boundaries and BB_HEAD/BB_END end up pointing to these notes. This > breaks verify_flow_info. > > The problem is actually bigger than just the var-tracking notes. The > general problem is that there are no rules for whether or not notes > are part of a basic block or not. Some notes never appear inside a > basic block, some notes always must appear inside a basic block, and > some can appear virtually anywhere. > > With this patch I've chosen to maintain the invariant that BB_END must > be an INSN, and never be a NOTE or BARRIER. The result is that > NOTE_INSN_EH_REGION_BEG notes can be inside a basic block while the > pairing NOTE_INSN_EH_REGION_END is outside the basic block. I don't > think this is a problem: The same thing already happens with jump > table data, barriers, etc. > > The nice thing is that with this patch, *finally* I have > verify_flow_info pass after var-tracking. That's important because > officially the CFG is freed after this pass (pass_free_cfg runs after > pass_variable_tracking) but because verify_flow_info didn't pass after > var-tracking the CFG was already invalidated before it was freed > (BB_HEAD and BB_END would be incorrect). That has the effect that some > of the machine-reorg passes that use the CFG never really had a > correct CFG at all! > > With this patch and a hack to call compute_bb_for_insn, I now can call > verify_flow_info in every pass up to final for the i386 port :-) > > Bootstrapped&tested on x86_64-unknown-linux-gnu and > powerpc64-unknown-linux-gnu. > OK for trunk? > > Ciao! > Steven
