[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 #10 from Richard Biener <rguenth at gcc dot gnu.org> 2012-11-28 
15:16:00 UTC ---

Caused by



2012-06-27  Richard Guenther  <rguent...@suse.de>



        PR middle-end/53676

        * tree-chrec.c (chrec_convert_1): Represent truncation to

        a type with undefined overflow as truncation to an unsigned

        type converted to the type with undefined overflow.

        * tree-scalar-evolution.c (interpret_rhs_expr): For computing

        the scalar evolution of a truncated widened operation avoid

        looking at the non-existing evolution of the widened operation

        result.