<div dir="ltr">Hey Amit,<div><br></div><div>EECS583 at Umich also has a homework assignment or two that you could give a go if you wanted.</div><div>HW2 asks you to extend the loop invariant code motion pass and do frequent path LICM (hoist almost invariant code).</div><div><br></div><div>Link below.</div><div><a href="https://web.eecs.umich.edu/~mahlke/courses/583f18/homeworks.html">https://web.eecs.umich.edu/~mahlke/courses/583f18/homeworks.html</a></div><div><br></div><div>It's just another resource.</div><div><br></div><div>Best of luck.</div><div><br></div><div>Regards,</div><div><br></div><div>Armand</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Dec 15, 2020 at 4:18 PM Stefanos Baziotis via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Amit,<br><br>There are the bugs tagged beginner but last time I checked, IMHO, they were not that "beginner-friendly" after all.<div><br></div><div>The way I would recommend that you start with LLVM is by rewriting a pass. One thing to note here is that this is not really a contribution (i.e.</div><div>a commit won't result immediately from that), so if you're only interested in contributing something with your first try, that won't do it.</div><div><br></div><div>But a common theme I see among beginners, including myself when I started, is that when you're obsessed with landing a commit,</div><div>unavoidably you're going to "hack your way towards it". That basically means that you'll just gather relatively shallow knowledge, maybe</div><div>with some breadth, but that limited too, just to commit something. That's bad and it will probably not serve you in the long run.</div><div><br></div><div>This is why for example, in courses which use LLVM as a teaching tool, the assignments don't ask you to do something</div><div>shallow like that but instead they ask for something that requires some kind of deep knowledge and thought (which you develop along).</div><div><br></div><div>To that end, I recommend rewriting a pass (which is btw somewhat common in courses). Now, that might sound scary but it's not.</div><div>The _actual_ goal is not to actually rewrite the pass. Neither all of it, nor at the production level of LLVM. Rewriting</div><div>the pass is just an "artificial goal" only to have something to move towards. The _actual_ goal is what you'll learn by moving</div><div>towards this goal. And what you'll learn will probably be both deep and broad.</div><div><br></div><div>You only need to start simple, like "OK, how do I query this analysis?". Just that, then you try something like "hmm, how can I inspect / traverse</div><div>the results of this analysis" etc. (and the good thing is that for a lot of these first steps, multiple other passes will have done the exact</div><div>same thing and you should feel free to copy code shamelessly as you're starting out).</div><div><br></div><div>After some time doing that, you'll find that you start understanding the system in some detail and _then_, you'll be equipped to do actual commits.</div><div><br></div><div>Now, the question is with which pass to start with? Again, because of the above, that doesn't really matter, but in any case, it depends on what you like.</div><div>For example, if you're interested in loops, I'd start with LCSSA (and along with it, I'd give a try to the LLVM Loop Terminology). If you're interested</div><div>in inter-procedural optimizations, I'd start with Sparse Conditional Constant Propagation (SCCP).</div><div><br></div><div>If you have no idea where to start or what you like, you might start with Scalar Replacement of Aggregates (SROA), just because I saw it</div><div>in a cool course on UIUC recently and it seems to guide you relatively well. Here's the link: <a href="http://misailo.web.engr.illinois.edu/courses/526-sp20/" target="_blank">http://misailo.web.engr.illinois.edu/courses/526-sp20/</a>,</div><div>it's project 1 (again, don't need to even do the whole thing, do the parts that motivate you; I mean please don't treat that as an _actual_ assignment,</div><div>you probably have enough of those already :) ).</div><div><br></div><div>So, this got very long, sorry for that, I hope it helps. Please don't hesitate to reach me for questions.</div><div><br></div><div>Best,</div><div>Stefanos</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Στις Τρί, 15 Δεκ 2020 στις 9:12 μ.μ., ο/η amit kumar via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> έγραψε:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Respected Sir/Ma'am,<br>
I'm Amit Kumar, a 3rd-year undergraduate<br>
student in Computer Science Engineering (CSE) from IIIT Nagpur, India.<br>
I am new to open source only contributed to HactoberFest in the past 2<br>
years and I came across LLVM through GSoC and interested in<br>
building some new features in the newer version's LLVM and contribute<br>
to the language. I had studied Compiler Design in our courses.<br>
<br>
Please help me and show me direction towards starting my journey to<br>
the open-source contribution.<br>
Thanks and Regards<br>
Amit Kumar<br>
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