http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53791
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-06-28
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-28
09:51:48 UTC ---
Confirmed. tree-ssa-ifcombine.c deals with two-comparison CFG patterns, so
it could handle transforming
# BLOCK 4 freq:9688 count:93
# PRED: 3 [96.9%] count:93 (false,exec)
if (xD.1241_2(D) == 2)
goto <bb 7>;
else
goto <bb 5>;
# SUCC: 7 [3.2%] count:3 (true,exec) 5 [96.8%] count:90 (false,exec)
# BLOCK 5 freq:9375 count:90
# PRED: 4 [96.8%] count:90 (false,exec)
if (xD.1241_2(D) == 3)
goto <bb 7>;
else
goto <bb 6>;
at least (and by iterating would then catch the 2nd opportunity). That's
of course somewhat ad-hoc (but the easiest place to implement).
The other trivially obvious possibility is to pattern-match this open-coded
switch/case and transform it back to switch/case early.
