Hi, thanks for the information, but LLVM still does <i>not</i> provide ABI compatibility.  If you reduce the struct to 3 i32, it is passed in edi, esi, and edx on my machine. However according to the ABI it should be packed in rdi and rsi.<p>Checkout the QBE transcription and what it will compile to <a href="http:&#x2F;&#x2F;c9x.me&#x2F;paste&#x2F;mGOO" rel="nofollow">http:&#x2F;&#x2F;c9x.me&#x2F;paste&#x2F;mGOO</a> (there is a bit of register shuffling because hinting in regalloc is not very mature yet, but note that SSA form for the input is not required!).