a patch for PR68695

[Christophe Lyon]

On 29 March 2016 at 18:28, Vladimir Makarov <vmakarov@redhat.com> wrote:
>   The following patch improves the code in 2 out of 3 cases in
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68695
>
>   The patch uses more accurate costs for the RA cost improvement
> optimization after colouring.
>
>   The patch was tested and bootstrapped on x86-64.  It is hard to create a
> test to check the correct code generation.  Therefore there is no test.  As
> the patch changes heuristics, a generated code in some cases will be
> different but at least x86-64 tests expecting a specific code are not broken
> by the patch.
>
>   Committed as rev.  234527
>

Hi,

I've noticed that after this patch, 2 tests regress (PASS -> FAIL) on arm:
  gcc.dg/ira-shrinkwrap-prep-2.c scan-rtl-dump pro_and_epilogue
"Performing shrink-wrapping"
  gcc.dg/pr10474.c scan-rtl-dump pro_and_epilogue "Performing shrink-wrapping"

Christophe