[PATCH, rs6000] Fix PR16458, eliminate redudant compares

[David Edelsohn]

On Tue, Apr 10, 2012 at 1:36 PM, Peter Bergner <bergner@vnet.ibm.com> wrote:

> 2012-mm-dd  Peter Bergner  <bergner@vnet.ibm.com>
>            Michael Matz  <matz@suse.de>
>
> gcc/
>        PR target/16458
>        * rtlanal.c (unsigned_reg_p): New function.
>        * rtl.h (unsigned_reg_p): Prototype it.
>        * config/rs6000/rs6000.c (rs6000_generate_compare): Use it.
>        Update comment.
>        * expr.c (expand_expr_real_1): Set register attributes.
>        * stmt.c (expand_case): Likewise.
>
> gcc/testsuite/
>        PR target/16458
>        * gcc.target/powerpc/pr16458-1.c: New test.
>        * gcc.target/powerpc/pr16458-2.c: Likewise.
>        * gcc.target/powerpc/pr16458-3.c: Likewise.
>        * gcc.target/powerpc/pr16458-4.c: Likewise.

The rs6000 and testsuite parts of the patch are okay with me.

Thanks, David