<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Ping?<div><br><div apple-content-edited="true">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">-Quentin</div>
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<br><div><div>On Jul 11, 2013, at 4:39 PM, Quentin Colombet <<a href="mailto:qcolombet@apple.com">qcolombet@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><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; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div>Hi,</div><div><br></div><div>Here is a patch that fixes a bug in IfConverter with nested predicates.</div><div><br></div><div>The problem seems so obvious that I am wondering if I am missing something.</div><div>So although the patch is straightforward (one line change), please review carefully.</div><div>Note: I have tested it with -O3 -arch armv7 (apple iOS) against both SingleSource and Multisource tests.</div><div><br></div><div>** Context **</div><div>Prior to this patch, IfConverter may widen the cases where a sequence of instructions were executed because of the way it uses nested predicates. This result in incorrect execution.</div><div><br></div><div><div style="margin: 0px;">For instance, Let A be a basic block that flows conditionally into B and B be a predicated block.</div><div style="margin: 0px;">B can be predicated with A.BrToBPredicate into A iff B.Predicate is less "permissive" than A.BrToBPredicate, i.e., iff A.BrToBPredicate subsumes B.Predicate.</div><div style="margin: 0px;"><br></div><div style="margin: 0px;">The IfConverter was checking the opposite: B.Predicate subsumes A.BrToBPredicate.</div><div style="margin: 0px;"><br></div><div style="margin: 0px;"><<a href="rdar://problem/14379453">rdar://problem/14379453</a>></div></div><div style="margin: 0px;"><br></div><div style="margin: 0px;">** Solution **</div><div style="margin: 0px;">Check the ‘subsumes’ property correctly.</div><div><br></div><div>Thanks for your review.</div><div><br></div><div>Cheers,</div><div><br></div><div apple-content-edited="true"><div style="font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">-Quentin</div></div><span><IfConverter.svndiff></span><span class="Apple-converted-space"> </span>_______________________________________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a></div></blockquote></div><br></div></body></html>