[LLVMdev] whether these transformations are doable and how?
Neal N. Wang
neal.wang at gmail.com
Wed Apr 14 18:38:09 PDT 2010
It's a silly question. I rephrase it as "is it possible to use different
instruction to def the same ssa variable?"
On Wed, Apr 14, 2010 at 5:45 PM, Neal N. Wang <neal.wang at gmail.com> wrote:
> Thanks for all the replies which are really helpful.
> one more question regarding transformation:
> 4. Given an instruction %x1 = I1, can I replace the rhs "I1" with "I2"
> and get a new instruction %x1 = I2? Alternatively, I can add a new
> instruction %x2 = I2, and replace all uses of %x1 with %x2, and then delete
> %x1 = I1, but it seems the former is simpler or faster if it's doable.
> Any suggestion?
> On Mon, Apr 12, 2010 at 11:20 PM, Devang Patel <devang.patel at gmail.com>wrote:
>> > 3. can I modify a function to take extra formal parameters? can I
>> > all calls of the original function to take extra actual paramters? The
>> > function might be called across multiple modules. It seems this has to
>> > done at both ModulePass and FunctionPass levels.
>> Check out DeadArgumentElimination pass. It does opposite of what you
>> want, but you'll get an idea.
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