[PATCH] More REG_EQ* notes cleanups

[Grigory Zagorodnev]

Steven Bosscher wrote:
> The patch is mostly mechanical, but there is one interesting change
> to local-alloc.c.  We used to turn REG_EQUAL notes into REG_EQUIV
> notes if the note datum was invariant.  But this is wrong if there
> is more than one set to the register that the REG_EQUAL note applies

Hi, Steven!
Unfortunately this patch resulted in output miscompare for two spec 
cpu2006 benchmarks 464.h264ref and 482.sphinx3 on i386-redhat-linux.

Bug report submitted: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30773

- Grigory