Inter-procedural optimization improvements:
- An Identical Code Folding (ICF) pass (controlled via
-fipa-icf) has been added. Compared to the identical code folding performed by the Gold linker this pass does not require function sections. It also performs merging before inlining, so inter-procedural optimizations are aware of the code re-use. On the other hand not all unifications performed by a linker are doable by GCC which must honor aliasing information. During link-time optimization of Firefox, this pass unifies about 31000 functions, that is 14% overall.