mold broken with musl llvm lto

[shortcircuitv]

Configuration:

Current /etc/portage/make.profile symlink:
  default/linux/amd64/23.0/musl/llvm

CHOST="x86_64-pc-linux-musl"
MAKEOPTS="-j16"
WARNING_FLAGS="-Werror=odr -Werror=strict-aliasing"
COMMON_FLAGS="-march=native -O3 -flto=thin -pipe ${WARNING_FLAGS}"
CFLAGS="${COMMON_FLAGS}"
CXXFLAGS="${COMMON_FLAGS}"
RUSTFLAGS="-C target-cpu=native -C linker-plugin-lto"
FCFLAGS="${COMMON_FLAGS}"
FFLAGS="${COMMON_FLAGS}"
LLVM_SLOT="19"
LDFLAGS="-Wl,-O1,--as-needed,-z,pack-relative-relocs -fuse-ld=mold"
USE="caps lto screencast zstd dist-kernel pipewire pulseaudio vaapi \
     -X -accessibility -gtk -vala -qt5 -tiff -gui -elogind"
ACCEPT_LICENSE="*"
ACCEPT_KEYWORDS="~amd64"
PORTAGE_COMPRESS="zstd"

[ebuild   R    ] sys-libs/musl-1.2.5-r3::gentoo  USE="-crypt -headers-only (-split-usr) -verify-sig" 0 KiB
[ebuild   R    ] sys-devel/mold-2.36.0::gentoo  USE="-debug -test" 0 KiB
[ebuild   R    ] llvm-core/llvm-19.1.7:19/19.1::gentoo  USE="binutils-plugin libffi xml* zstd -debug (-debuginfod) -doc -exegesis -libedit -test -verify-sig -z3" LLVM_TARGETS="(AArch64) (AMDGPU) (ARM) (AVR) (BPF) (Hexagon) (Lanai) (LoongArch) (MSP430) (Mips) (NVPTX) (PowerPC) (RISCV) (Sparc) (SystemZ) (VE) (WebAssembly) (X86) (XCore) -ARC -CSKY -DirectX -M68k -SPIRV -Xtensa" 0 KiB
[ebuild   R    ] llvm-core/clang-19.1.7:19/19.1::gentoo  USE="extra (pie) static-analyzer xml* -debug -doc (-ieee-long-double) -test -verify-sig" LLVM_TARGETS="(AArch64) (AMDGPU) (ARM) (AVR) (BPF) (Hexagon) (Lanai) (LoongArch) (MSP430) (Mips) (NVPTX) (PowerPC) (RISCV) (Sparc) (SystemZ) (VE) (WebAssembly) (X86) (XCore) -ARC -CSKY -DirectX -M68k -SPIRV -Xtensa" PYTHON_SINGLE_TARGET="python3_12 -python3_10 -python3_11 -python3_13" 0 KiB

example of package which fails only with lto enabled:

[ebuild   R    ] dev-libs/mpdecimal-4.0.0:4::gentoo  USE="-cxx -test" 0 KiB

log of failed package:
https://gist.github.com/shortcircuitv/22a76969fe3c0490e8250598b5a064a7