Messages in this thread | | | Date | Thu, 17 Apr 2003 12:54:30 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [BK+PATCH] remove __constant_memcpy |
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On Thu, 17 Apr 2003, Jeff Garzik wrote: > > __constant_memcpy was used for small, constant-sized cases AFTER > the kernel made the decision not to hand the copy duties over to the > kernel's MMX/SSE code. Take a look at the bottom of the patch below, > and also this snip from a non-hacked string.h, for illustration...
This is the part I don't like
#define memcpy(t, f, n) \ (__builtin_constant_p(n) ? \ - __constant_memcpy((t),(f),(n)) : \ + __builtin_memcpy((t),(f),(n)) : \ __memcpy((t),(f),(n)))
Notice? Our old __constant_memcpy() would do the rigth thing for large copies. In conrast, I don't know that gcc will do so.
Linus
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