<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Jan 10, 2012, at 8:46 AM, David Blaikie wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; 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-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">I haven't done any perf analysis yet - I was asking if there was any<br>recommended approach I should be using to make such measurements.<br><br>I'll take this answer as implying that there probably isn't much &<br>I'll have a first blush at making my own ad-hoc measurements. I'll<br>repost here once I have any numbers I think might be useful.</span></blockquote></div><br><div>That's not quite the message I was trying to convey. :)</div><div><br></div><div>As a first pass, I was wondering if you had observed anything noticeable before digging deeper.</div><div><br></div><div>I'd approach this as follows:</div><div><br></div><div>(1) Try running turning the warning on by default and run it through all of our benchmark tests, e.g. the GCC testsuite, clang tests, etc. See if there is a performance regression there. We regularly do this when measuring compile time regressions.</div><div><br></div><div>(2) Try building a few real world C++ codebases that are known to use templates (or otherwise make heavy use of C++) with this warning, e.g. Clang, Boost, Blender, Qt and see if there is a noticeable compile-time regression.</div><div><br></div><div>(3) While doing (2), see if the results of the warning (if any) are acceptable.</div><div><br></div><div>This is a fair amount of work, but it's the kind of thing we need to do to make this warning production quality.</div><div><br></div><div>Cheers,</div><div>Ted</div></body></html>