[Bug rtl-optimization/47270] [4.6/4.7/4.8 Regression] GCC produces unnecessary code on -O2 and -O3 levels

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47270



Steven Bosscher <steven at gcc dot gnu.org> changed:



           What    |Removed                     |Added

----------------------------------------------------------------------------

             Status|UNCONFIRMED                 |NEW

   Last reconfirmed|                            |2013-03-05

     Ever Confirmed|0                           |1



--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> 2013-03-05 
23:28:58 UTC ---

(In reply to comment #1)

> and RTL optimizations aren't able to undo that.  I doubt anything can

> be done about this easily.



Perhaps tree-ssa-uncprop should handle this.



FWIW, I've always thought that constant propagation into PHI arguments

was a mistake...