https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68274
--- Comment #2 from Matt Godbolt <matt at godbolt dot org> --- Thanks for updating the bug. As a corollary, moving the unreachability above the returns yields the same code as the non-unreachable: https://goo.gl/MdULOs -- int test_with_unreach_First(Side side, const Foo &foo) { if (side != Ask && side != Bid) __builtin_unreachable(); if (side == Bid) return foo.a; return foo.b; } -- test_with_unreach_First(Side, Foo const&): mov eax, DWORD PTR [rsi+4] test edi, edi cmove eax, DWORD PTR [rsi] ret -- For what it's worth I've been unable to coax either clang or icc (13.0.1 anyway) into the code I'd ideally like (the rsi+eax*4 case).
