After chrooting in stage3-i686 sync and do world upgrade rust package not emerging with error.
!!! The ebuild selected to satisfy "~dev-lang/rust-bin-1.46.0[-mgorny(-)]" has unmet requirements.
- dev-lang/rust-bin-1.46.0::lang-kit USE="-abi_riscv_lp64 -abi_riscv_lp64d -clippy -doc -rls -rustfmt" CPU_FLAGS_X86="-sse2"
The following REQUIRED_USE flag constraints are unsatisfied:
x86? ( cpu_flags_x86_sse2 )
(dependency required by "virtual/rust-1.46.0::lang-kit" [ebuild])
(dependency required by "gnome-base/librsvg-2.48.8::gnome-kit" [ebuild])
(dependency required by "x11-themes/adwaita-icon-theme-3.36.1::gnome-kit" [ebuild])
(dependency required by "x11-libs/gtk+-3.24.23-r1::gnome-kit" [ebuild])
(dependency required by "app-crypt/gcr-3.36.0::gnome-kit[gtk]" [ebuild])
(dependency required by "gnome-base/gnome-keyring-3.36.0::gnome-kit" [ebuild])
(dependency required by "app-crypt/libsecret-0.20.4::gnome-kit" [ebuild])
(dependency required by "app-crypt/pinentry-1.1.1::core-kit[gnome-keyring]" [ebuild])
(dependency required by "app-crypt/gnupg-2.2.27::core-kit" [installed])
(dependency required by "dev-vcs/git-2.31.1::core-kit[gpg]" [installed])
(dependency required by "@system" [set])
(dependency required by "@world" [argument])
Solved using epro subarch, wich support sse2 starting with p4