Re: [arm-gnu] NEON usage

[Daniel Jacobowitz <dan@xxxxxxxxxxxxxxxx>]

On Tue, May 11, 2010 at 01:20:10PM +1000, James wrote:
> $ arm-none-linux-gnueabi-gcc -O3 -march=armv7-a -mtune=cortex-a8
> -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp -ftree-vectorize
> -ftree-vectorizer-verbose=5 -ffast-math -fvect-cost-model  -o neon
> test.c
> 
> test.c:27: note: not vectorized: unsupported data-type int64_t
> test.c:21: note: vectorized 0 loops in function.
> 
> But the ARM NEON Intrinsics here:
> http://gcc.gnu.org/onlinedocs/gcc/ARM-NEON-Intrinsics.html
> 
> seems to suggest that 
> 
> int64x2_t vmlal_s32 (int64x2_t, int32x2_t, int32x2_t)
> 
> could be used?

Does it work any better with -mvectorize-with-neon-quad?

Currently released versions of GCC only support auto-vectorizing to a
single size; either double or quad, but not both.  A future version
will support automatic selection.  The infrastructure and some x86
support is expected in GCC 4.6, but I don't know when the equivalent
ARM pieces will be done.

-- 
Daniel Jacobowitz
CodeSourcery