This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
Hi,There is currently no pass which does "un-cse"; however, using insn splitting and operand costing and suitable insn constraints/predicates you can usually arrange to avoid expensive constants in places where it makes sense.
The constant propagation pass propagates constants into the instructions that accept immediates. I'm trying to find if there's some CSE pass in GCC that would be able to undo this effect when the constant is used more than once in the function. I looked at the CSE code (4.5 branch) and I don't think this is currently possible. If the code uses a bunch of big constants, the effect on code size might be quite sensible.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |