<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I've just had to do the same as I'm also looking at the optimisations that Clang/LLVM is performing on C code.</div><div class=""><br class=""></div><div class="">Given some of the names of latter passes seemed to include my target name (x86), even at -O0, I wondered if some of these optimisations were target specific.</div><div class=""><br class=""></div><div class="">Thus, I ran `clang -mllvm -debug-pass=Structure -S -emit-llvm -xc /dev/null --target='le64-unknown-unknown-unknown' -O$OPT_LEVEL` which seemed to give me a shorter list with fewer to no target/machine-specific optimisations. </div><div class=""><br class=""></div><div class="">This gives ~21 passes at -O0, ~202 at -O1, ~225 for -Os and -Oz, and ~230 for -O2, -O3, -Ofast (counting lines of output)</div><div class=""><br class=""></div><div class="">Assuming a "Pass Arguments" line specifies a new pass hierarchy inside LLVM, I'm still unsure as to why there are 4 hierarchies in for example the output of dumping the optimisations at -O1 (gist here: <a href="https://gist.github.com/anonymous/e71193ad5200bcc87b226374b7924365" class="">https://gist.github.com/anonymous/e71193ad5200bcc87b226374b7924365</a> )</div><div class=""><br class=""></div><div class="">Sam</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 4 Jul 2017, at 3:49 am, Martin J. O'Riordan via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">Thanks Sean,<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">My apologies for previously writing “Thanks Sean and Silva”, I intended “Thanks Sean and Ryan” - duh! - sleep deprived having just flown to the USA.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">The dump is very enlightening for me, and very large - I hadn’t realised that there were quite so many passes. At ‘</span><span style="font-family: 'Courier New';" class="">-O0</span><span style="font-family: 'Book Antiqua', serif;" class="">’ there are ~70 passes, but at ‘</span><span style="font-family: 'Courier New';" class="">-O1</span><span style="font-family: 'Book Antiqua', serif;" class="">’ it jumps to ~310 passes, and then ~340 passes at ‘</span><span style="font-family: 'Courier New';" class="">-O2</span><span style="font-family: 'Book Antiqua', serif;" class="">’ and ‘</span><span style="font-family: 'Courier New';" class="">-O3</span><span style="font-family: 'Book Antiqua', serif;" class="">’. I will have to carefully study these passes to see what optimisations they perform (if any), though there are the obvious ones too.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">One thing I observed, is that there are some passes that report:<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Courier New';" class="">Unnamed pass: implement Pass::getPassName()<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">This always appears after the final Target ‘</span><span style="font-family: 'Courier New';" class="">AsmPrinter</span><span style="font-family: 'Book Antiqua', serif;" class="">’ pass (“SHAVE Assembly Printer” in our case) and appears to be from the ‘</span><span style="font-family: 'Courier New';" class="">FPPassManager</span><span style="font-family: 'Book Antiqua', serif;" class="">’, while the other happens after ‘Global Variable Optimizer’ for optimisation levels of ‘</span><span style="font-family: 'Courier New';" class="">-O1</span><span style="font-family: 'Book Antiqua', serif;" class="">’ and higher and this seems to be the from the ‘</span><span style="font-family: 'Courier New';" class="">MPPassManager</span><span style="font-family: 'Book Antiqua', serif;" class="">’. I am using the release LLVM v4.0 sources, not the head revision. I guess these are noise and can be ignored.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">All the best,<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> MartinO<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class=""><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">From:</span></b><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span class="Apple-converted-space"> </span>Sean Silva [<a href="mailto:chisophugis@gmail.com" class="">mailto:chisophugis@gmail.com</a>]<span class="Apple-converted-space"> </span><br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>29 June 2017 04:15<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>ORiordan, Martin <<a href="mailto:martin.oriordan@intel.com" class="">martin.oriordan@intel.com</a>><br class=""><b class="">Cc:</b><span class="Apple-converted-space"> </span>Ryan Taylor <<a href="mailto:ryta1203@gmail.com" class="">ryta1203@gmail.com</a>>; Martin J. O'Riordan <<a href="mailto:martin.oriordan@movidius.com" class="">martin.oriordan@movidius.com</a>>; llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>><br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [llvm-dev] Definitive list of optimisations at each optimisation level<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On Mon, Jun 26, 2017 at 5:04 AM, ORiordan, Martin <<a href="mailto:martin.oriordan@intel.com" target="_blank" style="color: purple; text-decoration: underline;" class="">martin.oriordan@intel.com</a>> wrote:<o:p class=""></o:p></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin-left: 4.8pt; margin-right: 0cm;" class="" type="cite"><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">Thanks Sean and Silva.</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">I guess what I was seeking was a URL that I could point (non-compiler) people at, but I guess no such reference exists. What I can do if reference bot the source manager and use ‘-</span>mllvm -debug-pass=Structure’ for each optimisation level, and document that. The downside is that this will continuously go out of data with each release.<o:p class=""></o:p></div></div></div></blockquote><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Yeah, the nasty thing is that as each user of LLVM is running potentially different pass pipelines, we don't really have a good way to write a user-facing (or at least non-compiler-dev-facing) page describing the optimizations that they should expect the compiler to do, as the compiler developers using LLVM may have changed it. In theory, we could provide such a page for the open-source clang. Such a page of course couldn't go into massive detail about each pass and as such will likely be mostly describing the basics.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Most of the information that users would care about is likely to not get out of date very easily (e.g. we might switch GVN implementations, but the way in which they differ isn't going to be relevant to such a document; we might switch EarlyCSE to MemorySSA, but that isn't relevant to such a document).<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">-- Sean Silva<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin-left: 4.8pt; margin-right: 0cm;" class="" type="cite"><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">All the best,<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> MartinO<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">PS: Movidius is now part of Intel, so I will be gradually switching to my Intel email address.<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class=""><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">From:</span></b><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span class="Apple-converted-space"> </span>Ryan Taylor [mailto:<a href="mailto:ryta1203@gmail.com" target="_blank" style="color: purple; text-decoration: underline;" class="">ryta1203@gmail.com</a>]<span class="Apple-converted-space"> </span><br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>Sunday, June 25, 2017 2:59 AM<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>Sean Silva <<a href="mailto:chisophugis@gmail.com" target="_blank" style="color: purple; text-decoration: underline;" class="">chisophugis@gmail.com</a>><br class=""><b class="">Cc:</b><span class="Apple-converted-space"> </span>Martin J. O'Riordan <<a href="mailto:martin.oriordan@movidius.com" target="_blank" style="color: purple; text-decoration: underline;" class="">martin.oriordan@movidius.com</a>>; llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank" style="color: purple; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a>><br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [llvm-dev] Definitive list of optimisations at each optimisation level</span><o:p class=""></o:p></div><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">I agree, it's much clearer, it just takes runs at multiple opt levels and therefore I don't find it to be a "one stop shop". <o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On Jun 24, 2017 8:44 PM, "Sean Silva" <<a href="mailto:chisophugis@gmail.com" target="_blank" style="color: purple; text-decoration: underline;" class="">chisophugis@gmail.com</a>> wrote:<o:p class=""></o:p></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin: 5pt 0cm 5pt 4.8pt;" class="" type="cite"><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Looking at PassManagerBuilder can be useful because there are sometimes comments giving some idea of the intent of the particular choice of passes, but it can be difficult to see the big picture of all the passes that are run because it is very parameterized and split across multiple subroutines.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Running clang at O0 through O3 with -mllvm -debug-pass=Structure is generally more enlightening because then you see everything in one place for each optimization level.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">-- Sean Silva<o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On Jun 24, 2017 12:54 PM, "Ryan Taylor" <<a href="mailto:ryta1203@gmail.com" target="_blank" style="color: purple; text-decoration: underline;" class="">ryta1203@gmail.com</a>> wrote:<o:p class=""></o:p></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin: 5pt 0cm 5pt 4.8pt;" class="" type="cite"><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Right but then you'll have to call each opt level. Have u looked in the pass manager? <o:p class=""></o:p></div></div><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On Jun 24, 2017 3:52 PM, "Sean Silva via llvm-dev" <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank" style="color: purple; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a>> wrote:<o:p class=""></o:p></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin: 5pt 0cm 5pt 4.8pt;" class="" type="cite"><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">The most definitive list you can probably hope to get will be obtained by passing -mllvm -debug-pass=Structure to a clang invocation.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">-- Sean Silva<o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On Jun 24, 2017 7:10 AM, "Martin J. O'Riordan via llvm-dev" <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank" style="color: purple; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a>> wrote:<o:p class=""></o:p></div><blockquote style="border-style: none none none solid; border-left-width: 1pt; border-left-color: rgb(204, 204, 204); padding: 0cm 0cm 0cm 6pt; margin: 5pt 0cm 5pt 4.8pt;" class="" type="cite"><div class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">I am often asked what optimisations “our” compiler performs at each level. But “our” compiler is actually CLang/LLVM which we have retargeted to our proprietary target.</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">Most of the work we do is in maintaining our target specific backend. Certainly there are optimisations that we do to take best advantage of our instruction set during lowering and instruction selection, and we have also added a couple of additional passes which manipulate the IR in advance of lowering to better shape it for our target.</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">But in practice the vast majority of optimisations are contributed by the continuously evolving and excellent LLVM target independent passes, and have little or nothing to do with the work we do in our backend - though it is obviously directed/tuned by the various target call-backs and the target cost models.</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">Is there a “one stop shop” list of the optimisation passes that LLVM performs, and identification of which are enabled by default for each of the 4 standard optimisation levels ‘-O0’ thru ‘-O3’?</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">The reason that I ask, is that I really don’t have an honest or informed answer that I can provide to people when they ask, and I haven’t found a definitive statement of this in the LLVM documentation that I could refer them to.</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class="">Thanks,</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> MartinO</span><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-family: 'Book Antiqua', serif;" class=""> </span><o:p class=""></o:p></div></div></div><p class="MsoNormal" style="margin: 0cm 0cm 12pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><br class="">_______________________________________________<br class="">LLVM Developers mailing list<br class=""><a href="mailto:llvm-dev@lists.llvm.org" target="_blank" style="color: purple; text-decoration: underline;" class="">llvm-dev@lists.llvm.org</a><br class=""><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank" style="color: purple; text-decoration: underline;" class="">http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p class=""></o:p></p></blockquote></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""> <o:p class=""></o:p></div></div></div></div><p class="MsoNormal" style="margin: 0cm 0cm 12pt; font-size: 12pt; font-family: 'Times New Roman', serif;"><br class="">_______________________________________________<br class="">LLVM Developers mailing list<br class=""><a href="mailto:llvm-dev@lists.llvm.org" target="_blank" style="color: purple; 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<div style="color: rgb(0, 0, 0); letter-spacing: 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;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: 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;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: 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;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: 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;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: 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;" class=""><div class="">--</div><div class="">Archibald Sam Elliott</div><div class=""><a href="mailto:ashe2@cs.washington.edu" class="">ashe2@cs.washington.edu</a></div><div class="">PhD Student, PLSE Group</div></div></div></div></div></div>
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