Re: Undefined references to 'memcpy' when compiling Linux Kernel

From: Andi Kleen (ak@suse.de)
Date: Mon Jun 19 2000 - 04:27:14 EST


On Mon, Jun 19, 2000 at 10:14:42AM +0200, John Hughes wrote:
> I don't want to sound dumb; but does anyone know *why* it's not inlining
> the memcpy? It used to.

Inlined memcpy can be very big in some cases, e.g. when gcc cannot
figure out the alignment of the target and destination pointers
at runtime and has to add misalignment handling code. In this case
it is faster to outline to save some L1 cache. gcc 2.96 got new
heuristics for that now.

-Andi

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