RE: https://hachyderm.io/@pinskia/117254595282566244 GCC patches posted: https://gcc.gnu.org/pipermail/gcc-patches/2026-September/731050.html https://gcc.gnu.org/pipermail/gcc-patches/2026-September/731051.html The first one is exactly what the LLVM patch does. But the second one is needed for GCC code generation; I have not looked into why LLVM does not need a similar patch (a reduced testcase for LLVM fails in the same way as GCC did). I looked into libc++ code generation with push_back and I see the slow path is NOT inlined which might be causing performance issues too. libstdc++'s push_back inlined for both GCC and LLVM. GCC was also to shrink wrap the code but the LLVM bug there is https://github.com/llvm/llvm-project/issues/123120 .