<div dir="ltr"><div>That's an interesting bug. Can you post the pre-processed source code somewhere? I can't optimize the O0.ll file because it only contains the function, and none of the struct types.</div><div><br></div><div>Usually pre-processed source is large, so I wouldn't recommend mailing it to the list. I'd suggest our bugzilla, but you can't create new accounts right now without mailing llvm-admin.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 10, 2016 at 11:30 PM, Johan Wehrli via llvm-dev <span dir="ltr"><<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@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">HI,<div><br></div><div>When compiling the open-source software cryptopp (<a href="https://www.cryptopp.com/#download" target="_blank">https://www.cryptopp.com/#<wbr>download</a>) version 5.6.4 I found a strange issue with the IR generated.</div><div><br></div><div>The issue only appears when compiling with -O2 optimisation in the integer.cpp file (the function is _ZN8CryptoPPrsERNSt3__<wbr>113basic_istreamIcNS0_11char_<wbr>traitsIcEEEERNS_7IntegerE -> CryptoPP::operator>>(std::__1:<wbr>:basic_istream<char, std::__1::char_traits<char> >&, CryptoPP::Integer&)).</div><div><br></div><div>The verifier give me these errors:</div><div><br></div><div><div><i>EH pad cannot be in entry block. %4 = landingpad</i></div><div><i>{ i8*, i32 } cleanupLandingPadInst not the first non-PHI instruction in the block. %4 = landingpad { i8*, i32 } cleanup</i></div><div><br></div><div>If I remove the verifier, I am able to compile the whole library and run the test suite without any issue.</div><div><br></div><div>When you look at the whole IR code for the function:</div><div><br></div><div>----------------------</div><div><br></div><div><div>; Function Attrs: ssp uwtable</div><div>define nonnull dereferenceable(168) %"class.std::__1::basic_<wbr>istream"* @_ZN8CryptoPPrsERNSt3__<wbr>113basic_istreamIcNS0_11char_<wbr>traitsIcEEEERNS_7IntegerE(%"<wbr>class.std::__1::basic_istream"<wbr>* dereferenceable(168), %"class.CryptoPP::Integer"* dereferenceable(40)) local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {</div><div> %3 = tail call i8* @_<wbr>ZN8CryptoPP17UnalignedAllocate<wbr>Em(i64 16)</div><div> %4 = landingpad { i8*, i32 }</div><div> cleanup</div><div> %5 = icmp eq i8* %3, null</div><div> br i1 %5, label %6, label %8, !prof !22</div><div><br></div><div>; <label>:6: ; preds = %2</div><div> invoke void @__assert_rtn(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @__func__._<wbr>ZN8CryptoPP20AllocatorWithClea<wbr>nupIhLb0EE10deallocateEPvm, i64 0, i64 0), i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.64, i64 0, i64 0), i32 197, i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str.75, i64 0, i64 0)) #58</div><div> to label %7 unwind label %10</div><div><br></div><div>; <label>:7: ; preds = %6</div><div> unreachable</div><div><br></div><div>; <label>:8: ; preds = %2</div><div> %9 = tail call { i64, i8* } asm sideeffect "rep stosb", "={cx},={di},{ax},0,1,~{<wbr>memory},~{dirflag},~{fpsr},~{<wbr>flags}"(i32 0, i64 16, i8* nonnull %3) #53, !srcloc !1070</div><div> invoke void @_<wbr>ZN8CryptoPP19UnalignedDealloca<wbr>teEPv(i8* nonnull %3)</div><div> to label %13 unwind label %10</div><div><br></div><div>; <label>:10: ; preds = %8, %6</div><div> %11 = landingpad { i8*, i32 }</div><div> catch i8* null</div><div> %12 = extractvalue { i8*, i32 } %11, 0</div><div> tail call void @__clang_call_terminate(i8* %12) #59</div><div> unreachable</div><div><br></div><div>; <label>:13: ; preds = %8</div><div> resume { i8*, i32 } %4</div><div>}</div></div><div><br></div><div><div>----------------------</div></div><div><br></div><div>I was not able to understand which optimisation transforms the code like this.</div><div><br></div><div>I have attached the IR code from the function in O0 and O2.</div><div><br></div><div>Greetings,</div><div><br></div><div>Johan</div><div><br></div><div><br></div><div></div></div></div><br><div style="word-wrap:break-word"><div><div></div></div></div><br><div style="word-wrap:break-word"><div><div></div>
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