[LLVMdev] variant generation question
sabre at nondot.org
Fri Feb 9 19:42:52 PST 2007
On Fri, 9 Feb 2007, Scott Michel wrote:
> I would have expected four additional patterns, each with the (and $rC, $rA)
> variant in it. But I only get the above four.
> Is this a bug or a feature? :-)
This is a feature. They would match the same pattern, so it would just be
generating dead code. For the same reason, if you write something like:
(set $rd, (and $rs, 123))
you will only get matching code for that pattern, and not for:
(set $rd, (and 123, $rs))
which is always canonicalized to the former.
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