[LLVMdev] Memset/memcpy: user control of loop-idiom recognizer

Bruce Hoult bruce at hoult.org
Sat Dec 6 14:13:51 PST 2014


On Sun, Dec 7, 2014 at 10:48 AM, Joerg Sonnenberger <joerg at britannica.bec.de
> wrote:

> On Sat, Dec 06, 2014 at 07:06:31AM -0600, Hal Finkel wrote:
> >  - Direction (should the memory be traversed forward or backward)
>
> I don't think that this makes sense for memset and memcpy. It does
> matter for memmove.
>

This "memcpy" is being generated by pattern-matching an explicit loop in
the code. Direction is certainly something that needs to be kept the same
as the original loop, if there is overlap.
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