Promoting i386 version over x86_64?

[Andrew Haley]

Mike A. Harris wrote:
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> King InuYasha wrote:
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>> Except, that could be false advertising. In most cases, where CPU
>> computation is not used heavily, 64-bit is actually SLOWER than the
>> 32-bit counterpart. Optimizations are narrowing the gap, but it still
>> remains true. 
> 
> On ppc versus PPC64, sparc vs. sparc64, and possibly other architectures
> that may be true, however on x86 vs. x86_64 arch as a whole it is not
> generally the case, in particular because the x86_64 arch has double the
> number of available registers for gcc to play with.

Also, x86_64 has a much better ABI: args get passed in registers, not on
the stack.

> What applications are you aware of which run slower on x86_64 than on
> x86 on the same system?

There used to be Java slowdowns, but this was fixed with the "compressed
OOPs" option.

Andrew.