[LLVMdev] what is the Line number of Phi Node with addr2line

[Eric Lu]

By the way. When I remove these phi nodes with -reg2mem, some new load
operations will be inserted, but when I try cache load operations with:
visitFunction
visitLoadInst
It seems we can't see these new load operations.

On Wed, Apr 22, 2015 at 1:10 PM, Eric Lu <eirc.lew at gmail.com> wrote:

> Hi, Daniel
>
> I want to profile load/store operations, in order to reduce the overhead
> of profiling, I try to instrument the optimized llvm ir, which has phi
> nodes.
>
> BTW, when the value of some load/store operations may have multi-source,
> then the load will be translated into phi nodes, and all phi nodes are
> placed in the front of BB. Sometimes, the position is not where the load
> happens, is there any way to figure out where the load should be placed?(
> If the phi node translated back to load operations)
>
> Best Regards!
> Eric Lew
> On 周三, 4月 22, 2015 at 12:24 下午, Daniel Berlin <dberlin at dberlin.org> wrote:
>
> Hey Eric,
> phi nodes don't exist for real, so you can't.
> The are removed by PHI elimination as part of codegen.
>
> What are you trying to achieve?
>
>
>
>
> On Tue, Apr 21, 2015 at 9:12 PM, Eric Lu <eirc.lew at gmail.com> wrote:
> > Hi, all
> >
> >    When compiling a program with -g -O0, and if we have a PC, then with
> > addr2line, we can get the line number of the instruction.
> >
> > My quesions are:  what is the result of Phi node instruction, can we get
> the
> > similar results ?
> >
> > --
> > Best Regards!
> > Eric Lew
> >
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> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
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> >
>
>


-- 
Best Regards!
Eric Lew
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