Faster compilation speed

[David Edelsohn]

>>>>> Richard Henderson writes:

Richard> You havn't shown (or even provided guesstemates) how much temporal
Richard> or spacial locallity could be had by moving away from GC.  Exactly
Richard> how much garbage is created during compilation of a function, Dave?

Richard> Suppose we did do manual memory allocation and never created any
Richard> garbage whatsoever.  Suppose perfect temporal locality.  How much
Richard> spacial locality do we have, considering the pointer-chasing structure
Richard> of our IL?  My guess is not much.

	Places where GCC could benefit from spacial locality is by
allocating the instruction list and pseudo registers from a large, static
virtual memory array instead of allocating individual objects dynamically.
I am *not* suggesting removing the linked list pointers or the pointers to
the actual RTL.  GCC often scans or walks through the instructions
linearly.  Pseudo registers are allocated consecutively.  Allocating those
linearly-accessed objects in contiguous memory would improve cache
locality.

David