* config.gcc: Revamp target_cpu_default2 to strings;
support new x86 variants.
* i386.c (override_options): Default x86_cpu_string and x86_arch_string
properly; set prefetch_sse.
* i386.h (x86_prefetch_sse): Declare.
(TARGET_PREFETCH_SSE): New.
(CPP_CPU_DEFAULT_SPEC): Define according to the new macros.
(TARGET_CPU_DEFAULT_*): New.
* config/i386/i386.h (struct processor_costs): Add new members
prefetch_block and simultaneous_prefetches.
(PREFETCH_BLOCK, SIMULTANEOUS_PREFETCHES): New.
* config/i386/i386.c (processor_costs structs): Add values for
prefetch_block and simultaneous_prefetches.
* config/i386/i386.md (unspec values): Remove values for prefetch
operations, which now use the PREFETCH rtx code.
(prefetch_sse, prefetch_3dnow, prefetchw): Combine to use new
unified prefetch support.
From-SVN: r48006
