<div dir="ltr">Hi all -<br>There's another magic constant division codegen bug in:<br><a href="http://llvm.org/bugs/show_bug.cgi?id=20494">http://llvm.org/bugs/show_bug.cgi?id=20494</a><br><div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Mon, Aug 4, 2014 at 11:48 AM, Quentin Colombet <span dir="ltr"><<a href="mailto:qcolombet@apple.com" target="_blank">qcolombet@apple.com</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 style="word-wrap:break-word">Ping?<div><br></div><div>Benjamin, any idea on how we can write a test for the lowering of the low part of the MUL_LOHI on x86?</div>

<div><br></div><div>Thanks,</div><div>-Quentin</div><div><div><div><br><div><div>On Jul 29, 2014, at 9:22 AM, Quentin Colombet <<a href="mailto:qcolombet@apple.com" target="_blank">qcolombet@apple.com</a>> wrote:</div>

<br><blockquote type="cite"><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">

<div><br>On Jul 28, 2014, at 2:21 PM, Quentin Colombet <<a href="mailto:qcolombet@apple.com" target="_blank">qcolombet@apple.com</a>> wrote:</div><br><blockquote type="cite"><div style="word-wrap:break-word"><br><div>

<div>On Jul 28, 2014, at 12:58 PM, Chandler Carruth <<a href="mailto:chandlerc@gmail.com" target="_blank">chandlerc@gmail.com</a>> wrote:</div><br><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><br>

<div class="gmail_quote">On Mon, Jul 28, 2014 at 12:46 PM, Quentin Colombet<span> </span><span dir="ltr"><<a href="mailto:qcolombet@apple.com" target="_blank">qcolombet@apple.com</a>></span><span> </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 style="overflow:hidden">I think we still have a bug in the current implementation.<br>See my inline comments.<br></div></blockquote><div><br></div><div>Seems likely. Can you craft a test case to demonstrate it?</div>

</div></div></div></blockquote><div><br></div><div>I will see if I can come up with something.</div></div></div></blockquote><div><br></div><div>I haven’t found anything yet. The case I know that was using this path (div -> mul) just uses the high part of the result. Thus, the problem does not show up.</div>

<div><br></div><div>CC’ed Benjamin, he may have an idea on how to test that.</div><div><br></div><div>Cheers,</div><div>-Quentin</div><blockquote type="cite"><div style="word-wrap:break-word"><div><br><blockquote type="cite">

<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><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 style="overflow:hidden"><br>Also, I think it would be nice to update the comments on the masks value instead of removing them.<br>When I reversed engineered this code, it took me ages to figure out what were these magic values.</div>

</blockquote></div><br>I'm not sure that's going to help. The problem with comments is that they can get out of sync. I also don't think that little endian offsets are surprising or need lots of clarification here? The 1 instead of 0 thing you point out screams wrong to me at a glance, and I don't think a comment would really make it better (or worse, unless it got out of date).</div>

</div></blockquote></div><br><div>Fair enough!</div><div><br></div><div>-Quentin</div></div>_______________________________________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@cs.uiuc.edu" target="_blank">llvm-commits@cs.uiuc.edu</a><br>

<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><br></blockquote></div><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">

<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">_______________________________________________</span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">

<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">llvm-commits mailing list</span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">

<a href="mailto:llvm-commits@cs.uiuc.edu" style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" target="_blank">llvm-commits@cs.uiuc.edu</a><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">

<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a></blockquote>

</div><br></div></div></div></div><br>_______________________________________________<br>
llvm-commits mailing list<br>
<a href="mailto:llvm-commits@cs.uiuc.edu" target="_blank">llvm-commits@cs.uiuc.edu</a><br>
<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><br>
<br></blockquote></div><br></div></div></div>