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<p class="MsoNormal"><span lang="EN-GB">Hello Clang-Devs,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I run into a strange error with Clang-Cl - I hope I can explain it. We use Clang-Cl via the LLVM extension in Visual Studio and use it to compile our source code. One of the flags we set for the compiler is "/FA" which
gives us assembly output. Everything fine so far, no problems.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I then add a simple copy loop to our code, that is copying int32 values from one address to another one. When compiling this construct Clang-Cl suddenly exited with: "error: invalid instruction mnemonic 'movsdi'".<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However, when I remove the "/FA" flag everything compiles fine and runs fine in the end... Strangely, I couldn't figure out what the "movsdi" mnemonic is...<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The Assembly code looks like this:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">.LBB15_31: # in Loop: Header=BB15_17 Depth=1<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov ecx, 32<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov edx, 4<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> call calloc<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov qword ptr [r12 + rbp + 96], rax<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov qword ptr [r12 + rbp + 88], rax<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov ecx, 32<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> mov rdi, rax<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> rep movsdi es:[rdi], [rsi]<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> jmp .LBB15_33<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">My Clang-Cl version is:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">clang version 11.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a> 176249bd6732a8044d457092ed932768724a6f06)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Target: x86_64-pc-windows-msvc<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Thread model: posix<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The target is the same as in the version (x86_64-pc-windows-msvc).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Does anyone know what is going on? <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind greetings<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn<o:p></o:p></span></p>
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