This patch is a followup to D101178.
In the patch, we enable peephole optimization (when possible) for the toc data transformation.
For example, with this patch would allow for the following assembly code:
la 4, i[TD](2) stw 3, 0(4)
to be transformed to the following instead:
stw 3, i[TD](2)
This patch can only be merged in after D101178 has been accepted and merged into LLVM.