<div dir="ltr">+jakub<div><br></div><div>I don't think preservation should be controlled by a flag. That seems like not a great path forward.</div><div>Either we should make it fast enough, or we should give up :)</div><div><br></div><div>Do you have any profiles on this?</div><div><br><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 30, 2017 at 12:19 PM, Michael Zolotukhin via llvm-commits <span dir="ltr"><<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</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">For the record, we also detected significant compile-time increases caused by this patch. It caused up to 10% slow downs on sqlite3 and some other tests from CTMark/LLVM testsuite (on O3/LTO and other optsets).<div><br></div><div>Reproducer:</div><div><br></div><div>time clang-r314435/bin/clang -DNDEBUG -O3 -arch arm64 -isysroot $SYSROOT -DSTDC_HEADERS=1 -DSQLITE_OMIT_LOAD_EXTENSION=<wbr>1 -DSQLITE_THREADSAFE=0 -w -o sqlite3.c.o -c $TESTSUITE/CTMark/sqlite3/<wbr>sqlite3.c</div><div><div>real 0m20.235s</div><div>user 0m20.130s</div><div>sys 0m0.091s</div></div><div><br></div><div><div>time clang-r314432/bin/clang -DNDEBUG -O3 -arch arm64 -isysroot $SYSROOT -DSTDC_HEADERS=1 -DSQLITE_OMIT_LOAD_EXTENSION=<wbr>1 -DSQLITE_THREADSAFE=0 -w -o sqlite3.c.o -c $TESTSUITE/CTMark/sqlite3/<wbr>sqlite3.c</div><div><div>real 0m19.254s</div><div>user 0m19.154s</div><div>sys 0m0.094s</div></div><div><br></div><div>JumpThreading started to consume much longer time trying to preserve DT, but DT was still being recomputed couple of passes later. In general, I agree that we should preserve DT and in the end it should be beneficial for compile time too, but can we put it under a flag for now until we can actually benefit from it?</div><div><br></div><div>Thanks,</div><div>Michael</div><div></div></div><div><div class="h5"><div><br></div><div><br></div><div><div><blockquote type="cite"><div>On Sep 30, 2017, at 5:02 AM, Daniel Jasper via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>> wrote:</div><br class="m_5149017397612556239Apple-interchange-newline"><div><div dir="ltr">I found other places where this Clang was running into this segfault. Reverted for now in r314589.</div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 29, 2017 at 10:19 PM, Friedman, Eli via llvm-commits <span dir="ltr"><<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"><span>
<div class="m_5149017397612556239m_-3717849707277701947moz-cite-prefix">On 9/28/2017 10:24 AM, Evandro Menezes
via llvm-commits wrote:<br>
</div>
<blockquote type="cite">
<pre>Author: evandro
Date: Thu Sep 28 10:24:40 2017
New Revision: 314435
URL: <a class="m_5149017397612556239m_-3717849707277701947moz-txt-link-freetext" href="http://llvm.org/viewvc/llvm-project?rev=314435&view=rev" target="_blank">http://llvm.org/viewvc/llvm-pr<wbr>oject?rev=314435&view=rev</a>
Log:
[JumpThreading] Preserve DT and LVI across the pass
JumpThreading now preserves dominance and lazy value information across the
entire pass. The pass manager is also informed of this preservation with
the goal of DT and LVI being recalculated fewer times overall during
compilation.
This change prepares JumpThreading for enhanced opportunities; particularly
those across loop boundaries.
Patch by: Brian Rzycki <a class="m_5149017397612556239m_-3717849707277701947moz-txt-link-rfc2396E" href="mailto:b.rzycki@samsung.com" target="_blank"><b.rzycki@samsung.com></a>,
Sebastian Pop <a class="m_5149017397612556239m_-3717849707277701947moz-txt-link-rfc2396E" href="mailto:s.pop@samsung.com" target="_blank"><s.pop@samsung.com></a>
Differential revision: <a class="m_5149017397612556239m_-3717849707277701947moz-txt-link-freetext" href="https://reviews.llvm.org/D37528" target="_blank">https://reviews.llvm.org/D3752<wbr>8</a>
</pre>
</blockquote>
<br></span>
It looks like this is causing an assertion failure on the polly aosp
buildbot
(<a class="m_5149017397612556239m_-3717849707277701947moz-txt-link-freetext" href="http://lab.llvm.org:8011/builders/aosp-O3-polly-before-vectorizer-unprofitable/builds/266/steps/build-aosp/logs/stdio" target="_blank">http://lab.llvm.org:8011/buil<wbr>ders/aosp-O3-polly-before-vect<wbr>orizer-unprofitable/builds/<wbr>266/steps/build-aosp/logs/<wbr>stdio</a>):<br>
<pre style="font-family:'Courier New',courier,monotype,monospace;font-size:inherit;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px"><span class="m_5149017397612556239m_-3717849707277701947stdout" style="font-family:'Courier New',courier,monotype,monospace">clang: /var/lib/buildbot/slaves/hexag<wbr>on-build-03/aosp/llvm.src/<wbr>include/llvm/Support/GenericDo<wbr>mTreeConstruction.h:906: static void llvm::DomTreeBuilder::SemiNCAI<wbr>nfo<llvm::DominatorTreeBase<<wbr>llvm::BasicBlock, false> >::DeleteEdge(DomTreeT &, const BatchUpdatePtr, const NodePtr, const NodePtr) [DomTreeT = llvm::DominatorTreeBase<llvm::<wbr>BasicBlock, false>]: Assertion `!IsSuccessor(To, From) && "Deleted edge still exists in the CFG!"' failed.
#0 0x00000000014f6fc4 PrintStackTraceSignalHandler(v<wbr>oid*) (llvm.inst/bin/clang+0x14f6fc4<wbr>)
#1 0x00000000014f72d6 SignalHandler(int) (llvm.inst/bin/clang+0x14f72d6<wbr>)
#2 0x00007f694afddd10 __restore_rt (/lib/x86_64-linux-gnu/libpthr<wbr>ead.so.0+0x10d10)
#3 0x00007f6949bbb267 gsignal /build/buildd/glibc-2.21/signa<wbr>l/../sysdeps/unix/sysv/linux/<wbr>raise.c:55:0
#4 0x00007f6949bbceca abort /build/buildd/glibc-2.21/stdli<wbr>b/abort.c:91:0
#5 0x00007f6949bb403d __assert_fail_base /build/buildd/glibc-2.21/asser<wbr>t/assert.c:92:0
#6 0x00007f6949bb40f2 (/lib/x86_64-linux-gnu/libc.so<wbr>.6+0x2e0f2)
#7 0x000000000104a1dc (llvm.inst/bin/clang+0x104a1dc<wbr>)
#8 0x0000000001357fd9 llvm::JumpThreadingPass::Proce<wbr>ssBlock(llvm::BasicBlock*) (llvm.inst/bin/clang+0x1357fd9<wbr>)
#9 0x0000000001356e6e llvm::JumpThreadingPass::runIm<wbr>pl(llvm::Function&, llvm::TargetLibraryInfo*, llvm::LazyValueInfo*, llvm::AAResults*, llvm::DominatorTree*, bool, std::unique_ptr<llvm::BlockFre<wbr>quencyInfo, std::default_delete<llvm::Bloc<wbr>kFrequencyInfo> >, std::unique_ptr<llvm::BranchPr<wbr>obabilityInfo, std::default_delete<llvm::Bran<wbr>chProbabilityInfo> >) (llvm.inst/bin/clang+0x1356e6e<wbr>)
#10 0x0000000001363c49 (anonymous namespace)::JumpThreading::run<wbr>OnFunction(llvm::Function&) (llvm.inst/bin/clang+0x1363c49<wbr>)
#11 0x00000000010a53c4 llvm::FPPassManager::runOnFunc<wbr>tion(llvm::Function&) (llvm.inst/bin/clang+0x10a53c4<wbr>)
#12 0x00000000031f7376 (anonymous namespace)::CGPassManager::run<wbr>OnModule(llvm::Module&) (llvm.inst/bin/clang+0x31f7376<wbr>)
#13 0x00000000010a5b05 llvm::legacy::PassManagerImpl:<wbr>:run(llvm::Module&) (llvm.inst/bin/clang+0x10a5b05<wbr>)
#14 0x0000000001688beb clang::EmitBackendOutput(clang<wbr>::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwri<wbr>te_stream, std::default_delete<llvm::raw_<wbr>pwrite_stream> >) (llvm.inst/bin/clang+0x1688beb<wbr>)
#15 0x0000000001ed7672 clang::BackendConsumer::Handle<wbr>TranslationUnit(clang::ASTCont<wbr>ext&) (llvm.inst/bin/clang+0x1ed7672<wbr>)
#16 0x0000000002195235 clang::ParseAST(clang::Sema&, bool, bool) (llvm.inst/bin/clang+0x2195235<wbr>)
#17 0x0000000001a75628 clang::FrontendAction::Execute<wbr>() (llvm.inst/bin/clang+0x1a75628<wbr>)
#18 0x0000000001a37181 clang::CompilerInstance::Execu<wbr>teAction(clang::FrontendAction<wbr>&) (llvm.inst/bin/clang+0x1a37181<wbr>)
#19 0x0000000001b06501 clang::ExecuteCompilerInvocati<wbr>on(clang::CompilerInstance*) (llvm.inst/bin/clang+0x1b06501<wbr>)
#20 0x000000000080e433 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (llvm.inst/bin/clang+0x80e433)
#21 0x000000000080c997 main (llvm.inst/bin/clang+0x80c997)
#22 0x00007f6949ba6a40 __libc_start_main /build/buildd/glibc-2.21/csu/l<wbr>ibc-start.c:323:0
#23 0x0000000000809479 _start (llvm.inst/bin/clang+0x809479)
</span></pre>
I'll try to come up with a reduced testcase this afternoon.<br class="m_5149017397612556239m_-3717849707277701947Apple-interchange-newline">
<br>
-Eli<span class="m_5149017397612556239HOEnZb"><font color="#888888"><br>
<pre class="m_5149017397612556239m_-3717849707277701947moz-signature" cols="72">--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project</pre>
</font></span></div>
<br>______________________________<wbr>_________________<br>
llvm-commits mailing list<br>
<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits" rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-commits</a><br>
<br></blockquote></div><br></div>
______________________________<wbr>_________________<br>llvm-commits mailing list<br><a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a><br><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits" target="_blank">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-commits</a><br></div></blockquote></div><br></div></div></div></div><br>______________________________<wbr>_________________<br>
llvm-commits mailing list<br>
<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits" rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-commits</a><br>
<br></blockquote></div><br></div>