[Patch] Fix SSE2 packing intrinsics return type

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#1

Hi all,

Please consider committing the attached patch. I believe the SSE2 packsswb, packssdw and packuswb intrinsics have an incorrect return type.

Thanks,

Nicolas

PackSSE2.patch (1.18 KB)

#2

If we really wanted to do this, an AutoUpgrade patch would be
necessary for backwards-compatibility. I'm not sure it's worth
bothering.

-Eli

#3

Did they work before with llvm-gcc? If not, then don't worry about backward compatibility.

-Chris

#4

They work just fine as-is due to the rough equivalence of all SSE2
types; it's just not quite clean to use an i16 vector for the return
when the result actually contains i8s.

-Eli

#5

Hi Eli,

What exactly do mean by an AutoUpgrade patch?

I don't see how this could cause any issues with backward compatibility.
People currently using these intrinsics need a bitcast of the result to
avoid an assert, and with the patch applied the bitcast is no longer
necessary.

Cheers,

Nicolas

#6

What exactly do mean by an AutoUpgrade patch?

See lib/VMCore/AutoUpgrade.cpp.

I don't see how this could cause any issues with backward compatibility.
People currently using these intrinsics need a bitcast of the result to
avoid an assert, and with the patch applied the bitcast is no longer
necessary.

The issue isn't source-code compatibility (which we don't care about
anyway), but rather bitcode compatibility.

-Eli