Hi all,

This is a backport patch for branch 4.9. You can find the original patch 
here: https://gcc.gnu.org/ml/gcc-patches/2014-09/msg00356.html
And it has been commit on the trunk as r215205.

This fixes a few libstdc++-v3 test suite failures.
x86_64 bootstraps Okay, aarch64_be-none-elf libstdc++-v3 tested Okay.

Okay to commit on branch 4.9?

Regards,
Renlin Li

2015-02-06  Renlin Li  <renlin.li@arm.com>

     Backport from mainline
     2014-09-12  Wilco Dijkstra  <wilco.dijkstra@arm.com>

     * gcc/ree.c (combine_reaching_defs): Ensure inserted copy don't change
     the number of hard registers.