<div dir="ltr"><div>Hi Eli and All,</div><div><br></div><div>Thank you for the suggestions, the subjected review is blocking our internal release.</div><div><br></div><div>We would like to know community suggestions over the problem and fix , that we suggested.</div><div><br></div><div>Appreciate your time and thank you </div><div>~Umesh</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">---------- Forwarded message ---------<br>From: <strong class="gmail_sendername" dir="auto">Umesh Kalappa via Phabricator</strong> <span dir="auto"><<a href="mailto:reviews@reviews.llvm.org">reviews@reviews.llvm.org</a>></span><br>Date: Wed, May 13, 2020 at 10:02 AM<br>Subject: [PATCH] D79314: PR45733 : global weak symbol are excluded from the optimization .<br>To: <<a href="mailto:umesh.kalappa0@gmail.com">umesh.kalappa0@gmail.com</a>>, <<a href="mailto:renatoriolino@gmail.com">renatoriolino@gmail.com</a>>, <<a href="mailto:spatel@rotateright.com">spatel@rotateright.com</a>>, <<a href="mailto:tpr.ll@botech.co.uk">tpr.ll@botech.co.uk</a>>, <<a href="mailto:efriedma@quicinc.com">efriedma@quicinc.com</a>><br>Cc: <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>>, <<a href="mailto:88888yl@gmail.com">88888yl@gmail.com</a>>, <<a href="mailto:Samuel.j.knapp@btinternet.com">Samuel.j.knapp@btinternet.com</a>>, <<a href="mailto:florian_hahn@apple.com">florian_hahn@apple.com</a>><br></div><br><br>umesh.kalappa0 added a comment.<br>
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In D79314#2032099 <<a href="https://reviews.llvm.org/D79314#2032099" rel="noreferrer" target="_blank">https://reviews.llvm.org/D79314#2032099</a>>, @efriedma wrote:<br>
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> Okay, so assuming that optimization is invalid, there's a bug in clang *somewhere*. You haven't explained why this is the right fix.<br>
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> LLVM IR is a distinct language with its own specification. The definition of weak_odr is very explicitly written out. If you're going to change LLVM IR optimizations, you need to justify the change in terms of that specification, not C code.<br>
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In D79314#2032099 <<a href="https://reviews.llvm.org/D79314#2032099" rel="noreferrer" target="_blank">https://reviews.llvm.org/D79314#2032099</a>>, @efriedma wrote:<br>
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> Okay, so assuming that optimization is invalid, there's a bug in clang *somewhere*. You haven't explained why this is the right fix.<br>
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We are bailing out the optimization, if the global has the weak_odr linkage ,which is explicit in the condition check .<br>
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> LLVM IR is a distinct language with its own specification. The definition of weak_odr is very explicitly written out. If you're going to change LLVM IR optimizations, you need to justify the change in terms of that specification, not C code.<br>
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Yes, don't propagate the constant for the weak_odr / weak globals (in SCCP ).<br>
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