Creating llvmgcc42-2310 from top of tree.

llvm-svn: 82722
It seems safer to have the SSANames map take trees to AssertingVH's
rather than Value*'s.  It's still not completely clear to me whether
a value defining an SSAName can be deleted out from under us, so best
to check. 

llvm-svn: 82691
3 files changed