Combine subsequent Iconst_symbol instructions #5412
Original bug ID: 5412
This patch helps to reduce code size on load/store architectures (i.e. ARM) and with position independent code on amd64/i386, mostly for the generated __entry functions, which are usually up to 10-20% shorter (depending on arch).
Comment author: @xavierleroy
I've been working on a common subexpression elimination pass for the OCaml back-end, which, if successful, should subsume the factoring of Iconst_symbol instructions proposed here. The CSE is in branch branches/backend-optims of the OCaml SVN. Performance gains (on AMD64) are unimpressive so far, but I continue experimental evaluation in my spare time. To be continued.