[Bug middle-end/31862] Loop IM and other optimizations harmful for -fopenmp

[bonzini at gnu dot org]

------- Comment #24 from bonzini at gnu dot org  2009-02-25 18:43 -------
Andrew, your comments #6 #8 #9 clearly show that you haven't understood the
issue and are just talking past others.

The other hand the transformation has been shown to be an optimization on
single-thread cases; if it is bad for multiprocessors, it means it probably
should be guarded by a flag (but what if the load is not necessary?  should it
use the same flag, a separate flag, or be always enabled?).  But the IM code
should be modified to use the flag as suggested by the C++ standard (and to
avoid the load if it is not necessary, as it is in this case but not in the
case explained by N2238).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31862