<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: arial,helvetica,sans-serif; font-size: 10pt; color: #000000'><br><hr id="zwchr"><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><b>From: </b>"Xinliang David Li" <davidxl@google.com><br><b>To: </b>"Chandler Carruth" <chandlerc@gmail.com><br><b>Cc: </b>"Hal Finkel" <hfinkel@anl.gov>, "via llvm-dev" <llvm-dev@lists.llvm.org>, "Mehdi Amini" <mehdi.amini@apple.com><br><b>Sent: </b>Monday, April 18, 2016 6:38:32 PM<br><b>Subject: </b>Re: [llvm-dev] Move InlineCost.cpp out of Analysis?<br><br><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Apr 18, 2016 at 3:59 PM, Chandler Carruth <span dir="ltr"><<a href="mailto:chandlerc@gmail.com" target="_blank">chandlerc@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_quote"><span class=""><div dir="ltr">On Mon, Apr 18, 2016 at 3:45 PM Xinliang David Li <<a href="mailto:davidxl@google.com" target="_blank">davidxl@google.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth <span dir="ltr"><<a href="mailto:chandlerc@gmail.com" target="_blank">chandlerc@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_quote"><span><div dir="ltr">On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel <<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>> wrote:<br></div></span><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><span><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"><br><br><hr><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><b>From: </b>"Xinliang David Li" <<a href="mailto:davidxl@google.com" target="_blank">davidxl@google.com</a>><br></blockquote></div></div></span><span><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini <span dir="ltr"><<a href="mailto:mehdi.amini@apple.com" target="_blank">mehdi.amini@apple.com</a>></span> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div style="word-wrap: break-word;"><div><div>In the current case at stake: the issue is that we can't make the Analysis library using anything from the ProfileData library. Conceptually there is a problem IMO.</div></div></div></blockquote><div><br></div><div><br></div><div>Yes -- this is a very good point.</div></div></div></div></blockquote></div></div><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"></blockquote>Independent of anything else, +1.<br></div></div></span></blockquote><div><br></div><div>The design of ProfileData and reading profile information in the entire middle end had a really fundamental invariant that folks seem to have lost track of:</div></div></div></blockquote><div><br></div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Not sure about what you mean by 'lost track of'.</div></div></div></div></blockquote><div><br></div></span><div>I mean that we used to hold to these invariants but I think recently the code has started to not follow them as closely.</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_quote"><div><br></div><div>a) There is exactly *one* way to get at profile information from general analyses and transforms: a dedicated analysis pass that manages access to the profile info.</div></div></div></blockquote><div><br></div><div><br></div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>This is not the case as of today.</div></div></div></div></blockquote><div><br></div></span><div>Again, my whole comment was that these are no longer being correctly followed.</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div> BPI is a dedicated analysis pass to manage branch probability profile information, but this pass is only used in limited situations (e.g, for BFI, profile update in jump-threading etc) -- using it it requires more memory as well as incremental update interfaces. Many transformation passes simply skip it and directly access the meta data in IR.</div></div></div></div></blockquote><div><br></div></span><div>Can you be more specific?</div><div><br></div><div>BPI and BFI are used in *many* places, and on an initial inspection almost everywhere that accesses MD_prof directly appears to do so in order to *set* or *update* the profile information without doing detailed analysis on it. Which seems fine with my outline of the invariants?</div><span class=""><div> </div></span></div></div></blockquote><div><br></div><div>See my reply to Hal.</div><div> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_quote"><span class=""><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div class="gmail_quote"><div><span style="line-height: 1.5;"><br></span></div><div><span style="line-height: 1.5;">Now, the original design only accounted for profile information *within* a function body, clearly it needs to be extended to support intraprocedural information.</span></div></div></div></blockquote><div><br></div><div><br></div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Not sure what you mean. Profile data in general does not extend to IPA (we will reopen discussion on that soon), but profile summary is 'invariant'/readonly data, which should be available to IPA already.</div></div></div></div></blockquote><div><br></div></span><div>I don't know what you mean by "invariant" or readonly data here. I think that whether or not the profile information is mutated shouldn't influence the design invariants I described above.</div></div></div></blockquote><div><br></div><div><br></div><div id="DWT15001">I do not disagree with this. What I was saying is that the information can be made available to IPA in some form due to its readonly nature.</div></div></div></div></blockquote>Can you please clarify what information you view as readonly? I can understand function entry counts being readonly, but branch information within a function seems mutable. Is this also what you're talking about?<br><br> -Hal<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div></div><div><br></div><div>David </div></div><br></div></div>
</blockquote><br><br><br>-- <br><div><span name="x"></span>Hal Finkel<br>Assistant Computational Scientist<br>Leadership Computing Facility<br>Argonne National Laboratory<span name="x"></span><br></div></div></body></html>