alpha.c (alpha_cpu_name): New variable.

* alpha.c (alpha_cpu_name): New variable.
(alpha_mlat_string): Likewise.
(alpha_memory_latency): Likewise.
(override_options): Handle -mmemory-latency.
(alpha_adjust_cost): Adjust load cost for latency.
* alpha.h (TARGET_OPTIONS): Add meory-latency.
(REGISTER_MOVE_COST): Define in terms of memory_latency.  Take
TARGET_CIX into account.
(MEMORY_MOVE_COST): Define in terms of memory_latency.
* invoke.texi (DEC Alpha Options): Document -mmemory-latency.
* alpha.h (ASM_COMMENT_START): New macro.

From-SVN: r17106