<div dir="ltr">I reverted r191049 and r191059 from 3.4.</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Dec 4, 2013 at 10:00 AM, Evan Cheng <span dir="ltr"><<a href="mailto:evan.cheng@apple.com" target="_blank">evan.cheng@apple.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">This patch is hard to read. For example:<div><br></div><div><div>- if (HasROTRWithLArg || HasROTLWithLArg) {</div>
<div>+ ConstantSDNode *CN;</div><div>+ if (Use->getOpcode() == ISD::AND &&</div><div>+ (CN = dyn_cast<ConstantSDNode>(Use->getOperand(1))) &&</div><div>+ CN->getZExtValue()+1 == (1ULL << LArgVT.getSizeInBits())</div>
<div>+ && (HasROTRWithLArg || HasROTLWithLArg)) {</div><div><br></div><div><br></div><div>I would factor it out and match the earlier comment better. Perhaps something like:</div><div><br></div><div><div>
+ if (Use->getOpcode() == ISD::AND &&</div><div>+ && (HasROTRWithLArg || HasROTLWithLArg)) {</div></div><div>+ ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Use->getOperand(1));</div>
<div>+ // More comments here</div><div>+ if (CN &&</div><div><div>+ CN->getZExtValue()+1 == (1ULL << LArgVT.getSizeInBits())</div></div><div><br></div><div>This is also faster since the code delay the dyn_cast until cheaper conditions are checked.</div>
<div><br></div><div>Your description mentions "truncate". However, this is a AND masking, which is not quite the same.</div><div><br></div><div>As for 3.4, perhaps the safest thing to do now is to revert your patch r191059.</div>
<div><br></div><div>Evan</div><div><br></div><div><div><div class="h5"><div>On Dec 4, 2013, at 2:27 AM, Kai Nacke <<a href="mailto:kai.nacke@redstar.de" target="_blank">kai.nacke@redstar.de</a>> wrote:</div><br></div>
</div><blockquote type="cite"><div style="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><div class="h5">Ping^2.<br><br>This is a regression from LLVM 3.3 and should IMHO fixed - either by reverting my commit or by applying the attached fix.<br><br>Regards,<br>Kai<br><br>On 02.12.2013 08:13, Kai Nacke wrote:<br>
<blockquote type="cite">Ping.<br><br>On 25.11.2013 08:12, Kai Nacke wrote:<br><blockquote type="cite">Hi all!<br><br>With my commit r191059 I introduced new patterns to match rotates. But I<br>forgot to check for the required TRUNCATE after the rotate. The missing<br>
check produces wrong code as documented in PR17975.<br><br>The attached patch fixes the problem by adding the missing check. It<br>also extends the test to include patterns which must not produce a<br>rotate. Please review.<br>
<br>@Owen Anderson, Bill Wendling<br>If approved then this patch needs to be committed to the 3.4 branch. If<br>this seems to be to risky then my commit r191059 must be reverted on the<br>3.4 branch in order to fix the wrong code generation.<br>
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