[Bug rtl-optimization/48389] [4.5/4.6/4.7 Regression] ICE: in make_edges, at cfgbuild.c:319 with -mtune=pentiumpro

[matz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48389

--- Comment #11 from Michael Matz <matz at gcc dot gnu.org> 2011-04-08 13:05:18 UTC ---
I know what's the problem.  Your patch can't work.  commit_one_edge_insertion
relies on edge splitting to work, which relies on being able to patch jump
insns, which relies on correctly set JUMP_LABEL on those insns, hence
rebuild_jump_labels (which in this case doesn't rebuild but really initializes
JUMP_LABEL for the first time) must be called before inserting insns.

So, no it can't even theoretically work, except if we rewrite how
jumps are patched to redirect edges.

I'd propose to change the interface to rebuild_jump_labels somewhat to
only conditionally run over forced_labels.  Then it can be called on the
insn chains that are to be inserted on edges before insertion.