search for: preoptimization

...-mem2reg -loop-simplify -indvars $1.s> $1.preopt.ll >> opt -load ${PATH_TO_POLLY_LIB}/LLVMPolly.so -polly-detect -analyze $1.preopt.ll >> >> Using the instructions found on the Polly website. There are two reasons why it does not work with these instructions 1. Not the right preoptimization passes The instructions on the Polly website use a very short sequence of preoptimization passes that just matches the simple example presented. To optimize real world programs that are not 100% standard you need a larger sequence of prepasses. In your example the loop iv does not start at ...

I add also the output of these commands: [hades at artemis examples]$ ./compile_ex.sh super_simple_loop Printing analysis 'Polly - Detect Scops in functions' for function 'main': [hades at artemis examples]$ modifying it in : #include <stdio.h> int main() { int A[1024]; int j, k=10; for (j = 0; j < 1024; j++) A[j] = k;

Hi Tobias, thanks for the answer. I'll try to give a look to the code you pointed me to , and I'll try to make the modification myself. I'm new to LLVM and Polly, but the code of both seem clean and understandable, so I hope to be able to do it myself. In case I'll ask here for support :) Marcello 2011/10/1 Tobias Grosser <tobias at grosser.es>: > On 10/01/2011 03:26

...$1.preopt.ll >>> opt -load ${PATH_TO_POLLY_LIB}/LLVMPolly.so -polly-detect -analyze >>> $1.preopt.ll >>> >>> Using the instructions found on the Polly website. > > There are two reasons why it does not work with these instructions > > 1. Not the right preoptimization passes > > The instructions on the Polly website use a very short sequence of > preoptimization passes that just matches the simple example presented. To > optimize real world programs that are not 100% standard you need a larger > sequence of prepasses. In your example the loop iv d...

Here are some notes from the scalability session of last week''s Rails camp. They were entered by another session participant and are posted at: http://www.rubyonrailscamp.com/10%3A15%2Bsession%2B-%2Bscaling The key points from my point of view: - the Ruby VM is sketchy, rather like the Java VM around 1997 - the single threaded nature of Rails dispatch handling means we may incur a

...-polly-prepare: $ polly-opt -basicaa -polly-prepare -polly-scops nestedloop.preopt.ll -analyze Note that the region "for.cond2.preheader => for.end31" is reported as invalid as the exit BasicBlock has PHI nodes, if we run Polly without -polly-prepare. ># Time with and without preoptimization >~$ time polly-opt -basicaa -polly-prepare -polly-dependences >out.preopt.ll -disable-output >[..] > >Within -O3 the overhead is still far away from the 60 slowdown we have >seen on the other test case. A 2x slowdown for a kernel that we fully >analyse and code generate is n...

...one. ~$ polly-opt -basicaa -polly-prepare -view-scops out.preopt.ll -disable-output Writing '/tmp/scops-37f35f.dot'... done. Running 'xdot.py' program... done. # Print the scop info: $ polly-opt -basicaa -polly-prepare -polly-scops out.preopt.ll -analyze # Time with and without preoptimization ~$ time polly-opt -basicaa -polly-prepare -polly-dependences out.preopt.ll -disable-output real 0m0.040s user 0m0.032s sys 0m0.004s ~$ time polly-opt -basicaa -polly-dependences out.preopt.ll -disable-output real 0m0.011s user 0m0.004s sys 0m0.004s Looking at the timings, this does in fact not...

...e. > nestedloop.preopt.ll (http://llvm.org/bugs/attachment.cgi?id=11045): the preprocessed LLVM IR code. > nestedloop.prepare.ll (http://llvm.org/bugs/attachment.cgi?id=11046): the LLVM IR code after running the polly-prepare pass. Thanks, this works for me. >> # Time with and without preoptimization >> ~$ time polly-opt -basicaa -polly-prepare -polly-dependences >> out.preopt.ll -disable-output >> [..] >> >> Within -O3 the overhead is still far away from the 60 slowdown we have >> seen on the other test case. A 2x slowdown for a kernel that we fully >>...

Hi all, I have investigated the 6X extra compile-time overhead when Polly compiles the simple nestedloop benchmark in LLVM-testsuite. (http://188.40.87.11:8000/db_default/v4/nts/31?compare_to=28&baseline=28). Preliminary results show that such compile-time overhead is resulted by the complicated polly-dependence analysis. However, the key seems to be the polly-prepare pass, which introduces