On Tuesday, 14 April 2015 at 07:34:28 UTC, Ola Fosheim Grøstad
wrote:
VLAs can save stackspace compared to fixed max sized arrays,
but add recursion and try to figure out the right threshold
between small and large? You can't? So you need whole program
analysis...
To be clear: you get many of the same problems with fixed sized
arrays (but not all) if you cannot prevent recursion.
Maybe the better option is to have a pragmas for "max stack frame
size in bytes" and "max size for this VLA". Then you can estimate
the stack use by worst case recursive depth and let the backend
choose where to allocate if the max size for the VLA can exceed
the headroom left in a max-sized stack frame.
