Bit twiddling builtins
Richard Henderson
rth@redhat.com
Mon Feb 3 23:48:00 GMT 2003
On Mon, Feb 03, 2003 at 02:58:10PM -0800, Geoff Keating wrote:
> I don't really care about the user program; I'm much more interested
> in communicating with the middle-end of the compiler so it can apply
> the above transformation itself and the user program doesn't have to know.
Ah. Well in that case, I guess we could come up with something.
I guess I agree that when we do constant folding we should wind
up with something that matches what the target instruction would do.
I have no idea what you have in mind wrt ffs. Since (x == 0) can
be computed in parallel with ctz(x), I'm not sure why (ctz >> 5)
is interesting at all.
r~
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