http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56541
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-03-06
Blocks| |53947
Ever Confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2013-03-06
09:13:29 UTC ---
if-conversion is confused by the three-argument PHI node:
<bb 6>:
# rMin_3 = PHI <rMin_11(5), rMin_12(4), 1.5e+2(3)>
that occurs because of the forwarder block (which isn't one in the
case the addition appears). DOM produces this by threading
if (rMin_12 > 0.0)
goto <bb 4>;
else
goto <bb 5>;
<bb 4>:
<bb 5>:
# rMin_2 = PHI <rMin_11(4), 1.5e+2(3)>
if (rMin_2 > 0.0)
goto <bb 7>;
else
goto <bb 6>;
...
<bb 7>:
# rMin_3 = PHI <rMin_2(5), rMin_12(6)>
for rMin_2 == 1.5e+2. That's a good optimization.
