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[Bug rtl-optimization/15242] [3.3/3.4 regression] pessimization of "goto *"
- From: "steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 10 Mar 2005 12:48:09 -0000
- Subject: [Bug rtl-optimization/15242] [3.3/3.4 regression] pessimization of "goto *"
- References: <20040501142654.15242.anton@mips.complang.tuwien.ac.at>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From steven at gcc dot gnu dot org 2005-03-10 12:48 -------
> Maybe there should be another combining pass after the duplication
> of the indirect jumps. Should I create another PR for this?
There should not be another "combining" pass (you really mean constant
propagation). This new unfactoring stuff runs after register allocation,
so such a pass would not really help, except maybe to make the code look
prettier to you.
But, is this:
mov 0xfffffffc(%ebx),%eax
jmp *%eax
slower than this:
jmp *0xfffffffc(%ebx)
or have you not tried that (e.g. by hacking the assembly by hand)?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15242