memcpy embedded in gcc?

[Long Li <long21st@yahoo.com>]

Hi,

I am using a gcc 3.0.4 MIPS crosscompiler on Redhat. I
found something interesting: when I use specifly -O1
for compilation, and I can use memcpy function even I
did not tell the compiler where I declard it or define
it. However, when I specify -O0, then the compiler
tells me undefined reference to this memcpy function.
So my questions are:

1. Is memcpy a built-in function for gcc? But why not
for optimization level 0?

2. Besides memcpy, is there any other functions built
in too?


Thanks a lot!


Long


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