[LLVMdev] Question about simple constant propagation pass
zhangyunming1990 at gmail.com
Thu Mar 28 09:24:55 PDT 2013
Thanks a lot Duncan!!
It worked like magic,
On Thu, Mar 28, 2013 at 7:11 AM, Duncan Sands <baldrick at free.fr> wrote:
> Hi Yunming,
> On 28/03/13 03:15, yunming zhang wrote:
>> I just started working with llvm, I am trying to test and improve the
>> propagation pass (-constprop),
>> I have two main questions,
>> 1. I wrote my own test file, which has something like
>> int a = 1
>> int b = a + 2;
>> int c = b + 3;
>> print c
>> However, non of the instruction was killed according to -stat. I
>> think it
>> might due to the fact the llvm instructions generated was a bit
>> convoluted, but
>> overall, I am not sure why this simple test case has no instruction
>> Shouldn't c be just 6 and show at least two instructions killed?
> optimization passes usually assume you have run at least -mem2reg (or
> first and won't do much if you haven't.
> Ciao, Duncan.
>> 2. The description states that this pass is very simple. Can anyone point
>> me to
>> a few directions that might be interesting to improve it? I am not sure
>> why is it labeled "simple" ?
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
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