[Bug middle-end/55481] [4.8 regression] -O2 generates a wrong-code infinite loop in C++Benchmark's simple_types_constant_folding int8 xor test

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55481



--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> 2012-12-12 
13:07:26 UTC ---

Author: rguenth

Date: Wed Dec 12 13:07:19 2012

New Revision: 194444



URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194444

Log:

2012-12-12  Zdenek Dvorak  <o...@ucw.cz>



    PR tree-optimization/55481

    * tree-ssa-loop-ivopts.c (rewrite_use_nonlinear_expr): Fall

    back to general rewriting if we cannot leave an original biv

    definition alone.



    * gcc.dg/torture/pr55481.c: New testcase.



Added:

    trunk/gcc/testsuite/gcc.dg/torture/pr55481.c

Modified:

    trunk/gcc/ChangeLog

    trunk/gcc/testsuite/ChangeLog

    trunk/gcc/tree-ssa-loop-ivopts.c