On Mon, 28 Feb 2000, Jeff Garzik wrote:
> So... you are choosing to lose extremely valuable optimizations because
> of a few prototype warnings? This logic seems bogus to me... it also
OK, the problem is that gcc expects size_t to be an unsigned int. We use
unsigned long for size_t in the kernel because we want it to be 64 bits on
64-bit PPCs (like it is on the other 64-bit platforms). Gcc doesn't like a
prototype for memcpy which has an unsigned long for the 3rd argument
(unless you use -fno-builtin).
The only optimization we lose with -fno-builtin (that I can see) is that
the compiler won't turn explicit calls to memcpy with a small constant 3rd
argument (<= 32) into a sequence of inline loads and stores. (It still
does small struct copies with inline loads and stores even with
-fno-builtin.)
-- Paul Mackerras, Senior Open Source Researcher, Linuxcare, Inc. +61 2 6262 8990 tel, +61 2 6262 8991 fax paulus@linuxcare.com.au, http://www.linuxcare.com.au/ Linuxcare. Support for the revolution.- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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