<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>"Daniel Berlin" <dberlin@dberlin.org><br><b>To: </b>"Hal Finkel" <hfinkel@anl.gov><br><b>Cc: </b>"Raul Silvera" <rsilvera@google.com>, "Chandler Carruth" <chandlerc@gmail.com>, "David Majnemer" <david.majnemer@gmail.com>, "Nicolai Hähnle-Montoro" <nhaehnle@gmail.com>, "Chad Rosier" <mcrosier@codeaurora.org>, "llvm-commits" <llvm-commits@lists.llvm.org>, reviews+D9375+public+6271545f2d8b34dd@reviews.llvm.org<br><b>Sent: </b>Tuesday, August 16, 2016 4:26:39 PM<br><b>Subject: </b>Re: [PATCH] D9375: An llvm.noalias intrinsic<br><br><div dir="ltr">So i whiteboarded this, and i don't think there is a good way to do it given how often we destroy the types of info right now.<div>:(</div><div><br></div><div>I guess we'll just have to live with it for now.</div><div><br></div><div>Thanks for working through this with me, greatly appreciate it.</div><div><br></div><div>Other than calling it llvm.noalias.scope, i would think this is good to go :)</div><div id="DWT13055"><br></div></div></blockquote>Danny, et al.,<br><br>I just posted rebased versions of all of the patches in the patchset (in case that makes it easier to review). There are a few patches left that haven't been okayed yet:<br><br> <span class="phui-object-item-objname" style="color: rgb(0, 0, 0); cursor: text; font-weight: bold; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">D9401</span><span style="color: rgb(0, 0, 0); font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255); display: inline ! important; float: none;"><span class="Apple-converted-space"> </span></span><a href="https://reviews.llvm.org/D9401" class="phui-object-item-link" title="llvm.noalias - The AA implementaton" style="text-decoration: none; color: rgb(19, 108, 178); cursor: pointer; display: inline; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">llvm.noalias - The AA implementaton</a><br> <span class="phui-object-item-objname" style="color: rgb(0, 0, 0); cursor: text; font-weight: bold; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">D9378</span><span style="color: rgb(0, 0, 0); font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255); display: inline ! important; float: none;"><span class="Apple-converted-space"> </span></span><a href="https://reviews.llvm.org/D9378" class="phui-object-item-link" title="llvm.noalias - Add IRBuilder support" style="text-decoration: none; color: rgb(19, 108, 178); cursor: pointer; display: inline; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">llvm.noalias - Add IRBuilder support</a><br> <span class="phui-object-item-objname" style="color: rgb(0, 0, 0); cursor: text; font-weight: bold; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">D9400</span><span style="color: rgb(0, 0, 0); font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255); display: inline ! important; float: none;"><span class="Apple-converted-space"> </span></span><a href="https://reviews.llvm.org/D9400" class="phui-object-item-link" title="llvm.noalias - Use noalias intrinsics when inlining (and update them when cloning metadata)" style="text-decoration: none; color: rgb(19, 108, 178); cursor: pointer; display: inline; font-family: "Segoe UI","Segoe UI Web Regular","Segoe UI Symbol",Lato,"Helvetica Neue",Helvetica,Arial,sans-serif; font-size: 13px; font-style: normal; font-weight: bold; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: nowrap; widows: 2; word-spacing: 0px; background-color: rgb(255, 255, 255);">llvm.noalias - Use noalias intrinsics when inlining (and update them when cloning metadata)</a><br><br>I've been holding off on committing this patch until these others are reviewed (so that the intrinsic can actually mean something). Can you please review these?<br><br>Thanks again,<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></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Aug 16, 2016 at 11:31 AM, Daniel Berlin <span dir="ltr"><<a href="mailto:dberlin@dberlin.org" target="_blank">dberlin@dberlin.org</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"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Mon, Aug 15, 2016 at 8:18 PM, Hal Finkel <span dir="ltr"><<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"><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>"Daniel Berlin" <<a href="mailto:dberlin@dberlin.org" target="_blank">dberlin@dberlin.org</a>><br><b>To: </b>"Hal Finkel" <<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>><br><b>Cc: </b><a href="mailto:rsilvera@google.com" target="_blank">rsilvera@google.com</a>, "Chandler Carruth" <<a href="mailto:chandlerc@gmail.com" target="_blank">chandlerc@gmail.com</a>>, "David Majnemer" <<a href="mailto:david.majnemer@gmail.com" target="_blank">david.majnemer@gmail.com</a>>, "Nicolai Hähnle-Montoro" <<a href="mailto:nhaehnle@gmail.com" target="_blank">nhaehnle@gmail.com</a>>, "Chad Rosier" <<a href="mailto:mcrosier@codeaurora.org" target="_blank">mcrosier@codeaurora.org</a>>, "llvm-commits" <<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>>, <a href="mailto:reviews%2BD9375%2Bpublic%2B6271545f2d8b34dd@reviews.llvm.org" target="_blank">reviews+D9375+public+6271545f2d8b34dd@reviews.llvm.org</a><br><b>Sent: </b>Monday, August 15, 2016 10:03:58 PM<span><br><b>Subject: </b>Re: [PATCH] D9375: An llvm.noalias intrinsic<br><br></span><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"><span><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><br></div><span><div>The one without loop info, can be readnone.</div><div>The with loop info, we figure that out :)</div></span></div></div></div></blockquote></span><span>That sounds great, but I don't have any idea how that would work. </span></div></div></blockquote><span><div><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><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);">At the point in time when I insert the intrinsics, I'm either in the inliner or in the frontend, and I don't know anything about loops.</div></div></blockquote><div> <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><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);">Moreover, I might be inserting the intrinsics into places that won't obviously dominate, or be inside, loops until after inlining.<span style="font-family: arial,sans-serif; font-size: small; color: rgb(34, 34, 34);"> </span></div></div></blockquote><div> <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><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"> Even if I add loop information to the inliner (which we'll want to do anyway), having the inliner each for newly-dominating llvm.noalias intrinsics and fix them up with information about the newly-inserted loops seems asymptotically unfavorable.<br></div></div></blockquote><div><br></div><div>Note that if we do loop info in the inliner, and keep it up to date, you already have all the info you need to fix-them-up, and i guess i don't see what the issue is.</div><div><br>At worst, all you have to do is track what block these things appear in, and when loopinfo determines that block has a loop id, you promote them and give them that loop id...</div><div>When it determines a block no longer has a loop id, you demote them.</div><div>It already has to do all the real work to keep the loops up to date anyway ...<br></div></span></div></div></div></blockquote>Just to be clear, what I'm going to care about is finding intrinsics that dominate a given loop, not those in the loop.</div></div></blockquote><div><br></div></span><div>Ah. I would have figured you also cared about the intra-iteration intrinsic, and that would have appeared at the start of the loop body, since that is where the restrict scope ends up starting after inlining</div><span class=""><div><br></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: rgb(0, 0, 0);"> So either I need each loop to have some list of dominating intrinsics (i.e. originally dominating, neglecting any hosting that might occur), or each intrinsic needs a list of the loops it originally dominates. It is maintaining this that I was afraid could get expensive. These lists could be filtered by loops only containing some pointer based on the intrinsic (we can probably use a direct use/def check here because omission would be conservatively correct). Is your opinion still the same?</div></div></blockquote><div><br></div></span><div>Let me see how often we destroy loopinfo.</div><div><br></div><div>The ideal non-loop way to store this is to just augment dominator tree nodes, or store it associated with the dfs numbers in the domtree (which would allow collection for a given loop in O(level depth of dom tree) time, but we definitely destroy that too much.<br></div><div><br></div></div></div></div>
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</blockquote><br><br><br>-- <br><div><span name="x"></span>Hal Finkel<br>Lead, Compiler Technology and Programming Languages<br>Leadership Computing Facility<br>Argonne National Laboratory<span name="x"></span><br></div></div></body></html>