As a final step to compute the product of two complex numbers I perform a simd operation on double2:

x3 = [x3.array[1] - x2.array[1], x3.array[0] + x2.array[0]];

But ldc2 compiles that quite badly (I don't know who's to blame, if necessary I will open a LLVM bug report), so I have tried to use an instruction addsubpd.

To do it I have imported ldc.gccbuiltins_x86 and then I use:

x3 = __builtin_ia32_addsubpd(x3, x2);

but ldc2 gives me:

LLVM ERROR: Cannot select: intrinsic %llvm.x86.sse3.addsub.pd
Stack dump:
0.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@"\01__D12complex_mul217__T8compMul6Vk12Z8compMul6FNaNbNfKG12NhG2dKG12NhG2dKG12NhG2dZv"'

Can you help me?

Bye,
bearophile

Try adding flag -mattr=sse3.

jerro:

> Try adding flag -mattr=sse3.

Now it's accepted, thank you. So is LDC2 assuming a very old CPU? :-)

Bye,
bearophile

On Thursday, 18 July 2013 at 21:30:12 UTC, bearophile wrote:
> jerro:
>
>> Try adding flag -mattr=sse3.
>
> Now it's accepted, thank you. So is LDC2 assuming a very old CPU? :-)
>
> Bye,
> bearophile

Hi,

the behaviour was changed because you can't create a generic package if you optimize for your CPU.

But the change created other problems, see issue #414 (https://github.com/ldc-developers/ldc/issues/414).

With LLVM 3.3, the auto vectorizer is not enabled. You have to specify -vectorize on the command line. Maybe you want to try that with your original code.

Kai