I am looking at a related problem in GCSE, GCC 4.3 whereby constants are propagated to their use irrespective of the final instruction cost of generating them (machine cycles or instruction count).
Global constant propagation effectively voids common expressions that form large constants, identified by global CSE. This is especially true of SYMBOl_REF constants like section-anchors generated while indexing global arrays. For the GCC port I work on, I have fixed this by weighing the rtx_cost of propagating a register copy Vs propagating the constant into an insn. I have an initial patch for this problem. Rahul Vijay Kharche
