c:\msys64\home\ipc\rust>rustup toolchain link latest-stage2 build\x86_64-pc-windows-gnu\stage2

c:\msys64\home\ipc\rust>rustup default latest-stage2
info: default toolchain set to 'latest-stage2'

c:\msys64\home\ipc\rust>rustup which rustc
C:\Users\ipc\.rustup\toolchains\latest-stage2\bin\rustc.exe

c:\msys64\home\ipc\rust>rustc -vV
rustc 1.29.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-pc-windows-gnu
release: 1.29.0-dev
error: couldn't load codegen backend "C:\\msys64\\home\\ipc\\rust\\build\\x86_64-pc-windows-gnu\\stage2\\lib\\rustlib\\x86_64-pc-windows-gnu\\codegen-backends\\rustc_codegen_llvm-llvm.dll": "The specified module could not be found. (os error 126)"

c:\msys64\home\ipc\rust>C:\msys64\usr\local\bin\rustc -Vv
rustc 1.29.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-pc-windows-gnu
release: 1.29.0-dev
LLVM version: 7.0