GIMPLE pass - Assignment evaluation

Sandeep K Chaudhary
Mon Dec 9 23:05:00 GMT 2013

Hi Guys,

I am writing a GIMPLE pass in which I need to inspect the assignments.
For example, for the below statements, I need to find the value of the
second and third assignments which are '2' and '7'.

VAR1 = 1;
VAR1 = VAR1 + 5;

But the GIMPLE IR only has the following statements i.e. no optimization.

  VAR1_2 = 1;
  VAR1_3 = VAR1_2 + 1;
  VAR1_4 = VAR1_3 + 5;

How can I make it perform calculations on RHS? Are there some flags
that I can enable?

I tried -O1 and higher optimization levels but I don't see any
difference. This is how I am building and loading my plugin...

g++ -I`g++ -print-file-name=plugin`/include -fPIC -shared -O1
gimple_pass.c -o
g++ -fplugin=/home/sandeep/myplugin/gimple/ -O1 -c test.c

Also, I thought of going with RTL passes but RTL IR seems too complex
for my use and also it's not suitable for high level optimizations.
Please suggest.

Thanks and regards,

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