Re: SSA-form and cmove (Hannah Schroeter)
13 Sep 2000 21:10:39 -0400

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SSA-form and cmove (Tommy Hoffner) (2000-08-13)
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Re: SSA-form and cmove (2000-09-13)
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From: (Hannah Schroeter)
Newsgroups: comp.compilers
Date: 13 Sep 2000 21:10:39 -0400
Organization: Chaos
References: 00-08-066
Keywords: analysis


Tommy Hoffner <> wrote:
>[... conditional move vs. SSA ...]

Couldn't this be handled like just another operator, just like
plus or something like that?

i.e. (like v_new := v_old1 + v_old2)
v_new:= condition ? v_old1 : v_old2

(and cmove dest, src, condition is just
dest_new:= condition ? src : dest_old with a desire to
coalesce dest_new and dest_old).

In this view, I don't see the need for a phi-node there, however,
transformations should know that if they can prove condition is
true, that's equivalent to dest_new := src (and dest_old is dead),
and if condition is false, that's dest_new := dest_old (and src is dead).

Kind regards,


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