<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Jun 8, 2012, at 2:55 PM, John Criswell wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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On 6/8/12 12:47 PM, Peter Cooper wrote:
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<div class="PlainText">Hi all<br>
<br>
Attached is a pass to make the SimplifyCFGPass preserve
the dominator tree. Currently we see lots of
recalculations of the dom tree right after simplify cfg
runs, regardless of whether simplify cfg actually did
anything.<br>
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Does SimplifyCFGPass return false from its run method when it
doesn't change anything? If so, does the PassManager just
invalidate DomTree anyway because SimplifyCFGPass does not claim to
preserve it?<br></div></blockquote>It does return false in this case, yeah, but the pass manager actually invalidates it anyway. I don't think it trusts the return value because some passes (like simplify lib calls) actually return false even if they did something.</div><div><br></div><div>Pete<br><blockquote type="cite"><div bgcolor="#FFFFFF" text="#000000">
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-- John T.<br>
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<br>
Thanks,<br>
Pete<br>
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