middle-end/112785 - guard against last_clique overflow
The PR shows that we'll ICE eventually when last_clique wraps. The
following avoids this by refusing to hand out new cliques after
exhausting them. We then use zero (no clique) as conservative
fallback.
PR middle-end/112785
* function.h (get_new_clique): New inline function handling
last_clique overflow.
* cfgrtl.cc (duplicate_insn_chain): Use it.
* tree-cfg.cc (gimple_duplicate_bb): Likewise.
* tree-inline.cc (remap_dependence_clique): Likewise.