Forcing the compiler to use a certain register for a certain variable
c, clang, gcc, linux, x86-64
Solution
gcc can do it.
The already cited gcc docs answers your question of how to force a variable into a certain register.
To stop the compiler from generating code using this register for other purposes, use the gcc switch `-ffixed-reg` (see gcc doc for details).
Problem
Is it possible to force a compiler (`gcc` or `clang` in my case) to use a certain register, lets say `R15` on `x86_64` for a certain variable and also prohibit it from using `R15` for any other purpose besides that variable.