possible gcse failure: not able to eliminate redundant loads

[Sanjiv Kumar Gupta, Noida]

>> We have the code for it, but alias.c isn't helping.

>It looks like memrefs_conflict_p is supposed to be able to prove that
a[2] and a[4] don't alias, I wonder why it's not working?

It can detect different offsets in 'reg+offset' forms of addresses
but can not distinguish between two pointer regs. 
In this case, the machine (sh4) doesn't support reg+offset addressing
for double-precision values.
I am working on memrefs_conflict_p to handle this.

--Sanjiv