[Bug middle-end/32758] [4.3 Regression] ecj1 hangs

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

------- Comment #27 from bonzini at gnu dot org  2007-08-29 14:11 -------

> Not all basic blocks have all 4 x86_64 regular_block_artificial_regs registers
> set in DF_LR_IN and so oring this in causes infinite loop, as process_dce_block
> always returns something changed.

If so, your previous patch would be correct.  But in that case I wonder:

1) what is the purpose df_simulate_fixup_sets in df_simulate_one_insn_backwards
(and df_simulate_one_insn_forwards, FWIW).  Doing the OR for every insn is
clearly wrong, if it doesn't result in the IN set equal to DF_LR_IN.

2) why is the code marked as 

  /* Process the artificial defs and uses at the bottom of the block.  */

in dce_process_block slightly different from df_simulate_artificial_refs_at_end
and df_simulate_artificial_refs_at_top.

3) whether the code you added in dce_process_block should go in
df_simulate_artificial_refs_at_end actually.

Post your first patch, I will try to sort out this mess next week and may ask
you to regtest a patch on at least x86_64 and ia64.  In the meanwhile I CCed
Zadeck so that he can answer these questions...


-- 

bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zadeck at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32758