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From: "vries at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/105075] [nvptx] Generate sad insn (sum of absolute
 differences)
Date: Mon, 28 Mar 2022 08:13:26 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105075

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
AFAIU, at gimple level support is limited to vectors, so that doesn't help =
to
generate the insn for the simple, scalar case.

It would be nice if combine could generate it and we wouldn't have to use a
peephole, but AFAIU the pattern is too complex for that.

I wonder if reformulating using a conditional could help there (ptx isa
describes semantics using "c + ((a<b) ? b-a : a-b)".

Also, I wonder if defining a stepping-stone intermediate pattern could help
combine.=