[Issue 23641] core.simd.int4 multiplication

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23641

Walter Bright <bugzilla at digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla at digitalmars.com
         Resolution|---                         |INVALID

--- Comment #3 from Walter Bright <bugzilla at digitalmars.com> ---
This behavior of DMD is as designed. (As mentioned here, it will work if the
-mcpu=avx switch is used.)

Workarounds can be much much slower than the native instructions. The user may
not realize that a slow workaround is happening. By notifying the user that the
native instruction for it does not exist, the user can then deliberately choose
the workaround that works best for his particular application. In particular,
the user may not actually need the full capability of the native instruction,
so using a full semantic workaround is a pessimization. Or a different
algorithm can be selected that does not require the missing native instruction.

This behavior comes at the request of Manu Evans, who spends a lot of time
coding high performance vector code.

GDC and LDC have a different philosophy about this, which is their prerogative.

Therefore, I'm going to mark this as INVALID, as the behavior is deliberate and
not a bug.

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