On Fri, Dec 6, 2019 at 12:15 PM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Fri, Dec 06, 2019 at 11:48:03AM +0100, Richard Biener wrote:
> > So I used
> >
> > void sincos(double x, double *sin, double *cos);
> > _Complex double __attribute__((__simd__("notinbranch")))
> > __builtin_cexpi (double);
>
> While Intel-ABI-Vector-Function-2015-v0.9.8.pdf talks about complex numbers,
> the reason we punt:
> unsupported return type ‘complex double’ for simd
> etc. is that we really don't support VECTOR_TYPE with COMPLEX_TYPE element
> type, I guess the vectorizer doesn't do anything with that either unless
> some earlier optimization was able to scalarize the complex halves.
> In theory we could represent the vector counterparts of complex types
> as just vectors of double width with element type of COMPLEX_TYPE element
> type, have a look at what exactly ICC does to find out if the vector
> ordering is real0 complex0 real1 complex1 ... or
> real0 real1 real2 ... complex0 complex1 complex2 ...
> and tweak everything that needs to cope.
I hope real0 complex0, ...
Anyway, the first step is to support vectorizing code where parts of it are
already vectors:
typedef double v2df __attribute__((vector_size(16)));
#define N 1024
v2df a[N];
double b[N];
double c[N];
void foo()
{
for (int i = 0; i < N; ++i)
{
v2df tem = a[i];
b[i] = tem[0];
c[i] = tem[1];
}
}
that can be "re-vectorized" for AVX for example. If you substitute
_Complex double for the vector type we only handle it during
vectorization because forwprop combines the load and the
__real/imag which helps.
Richard.
> Jakub
>
