LLVM is able to merge identical static const globals, GCC isn't, and this caused
some bloat in the generated data.  This has a marginal effect on PPC, shrinking
the implicit sets from 10->4, but shrinks X86 from 179 to 23, a much bigger
reduction.

This should speed up the register allocator as well by reducing the dcache
footprint for this static data.

llvm-svn: 22879