[LLVMdev] reg_iterator Caveats
sabre at nondot.org
Mon Mar 31 16:55:31 PDT 2008
On Mon, 31 Mar 2008, Evan Cheng wrote:
>> I just discovered that def_itterator (and presumably, reg_iterator)
>> include implicit defs, for example at function calls for caller-save
>> registers. Guh. I'm not sure if it should or not, but it's certainly
>> necessary information in some cases. Is this expected behavior, or an
reg iterators will return everything that is in the function. If the
implicit operands haven't been added to the machieninstrs yet, then they
won't be returned.
> MachineRegisterInfo tracks virtual register only.
It works for vregs and pregs today.
> I also wish it would track physical register defs and uses as well. It
> can be used to simplify a lot of code (in livevariable, etc.). Chris,
> do you think that's feasible?
Really really feasible :)
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