[Tinycc-devel] avoid needless register save when storing structures

[Jörg Mische]

Hi all,

I found a small bug when storing structures in vstore(): the store is done by a 
call to memcpy() and the arguments are pushed on vstack. But there remains an 
unused entry on the stack that is popped after the
code generation for the call (in gfunc_call()).

This should not be a problem, but gfunc_call() calls save_regs() which searches 
the vstack for registers that must be preserved during a function call. If the 
unused entry refers to a register, it is saved to memory, although it will 
never be used again.

By avoiding the unused entry, the needless code generation can be avoided, too. 
I pushed a patch on the "mob" branch.

Regards,
Jörg

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