> -----Original Message-----
> From: Richard Biener <richard.guent...@gmail.com>
> Sent: Tuesday, August 20, 2024 1:54 PM
> To: Tamar Christina <tamar.christ...@arm.com>
> Cc: Victor Do Nascimento <victor.donascime...@arm.com>; gcc-
> patc...@gcc.gnu.org; claz...@gmail.com; hongtao....@intel.com;
> s...@gcc.gnu.org; bernds_...@t-online.de; al...@redhat.com; Victor Do
> Nascimento <vicdo...@e125768.arm.com>
> Subject: Re: [PATCH V3 10/10] autovectorizer: Test autovectorization of
> different
> dot-prod modes.
>
> On Tue, Aug 20, 2024 at 12:04 PM Tamar Christina
> <tamar.christ...@arm.com> wrote:
> >
> > > -----Original Message-----
> > > From: Richard Biener <richard.guent...@gmail.com>
> > > Sent: Tuesday, August 20, 2024 10:37 AM
> > > To: Victor Do Nascimento <victor.donascime...@arm.com>
> > > Cc: gcc-patches@gcc.gnu.org; Tamar Christina <tamar.christ...@arm.com>;
> > > claz...@gmail.com; hongtao....@intel.com; s...@gcc.gnu.org; bernds_cb1@t-
> > > online.de; al...@redhat.com; Victor Do Nascimento
> > > <vicdo...@e125768.arm.com>
> > > Subject: Re: [PATCH V3 10/10] autovectorizer: Test autovectorization of
> different
> > > dot-prod modes.
> > >
> > > On Thu, Aug 15, 2024 at 10:46 AM Victor Do Nascimento
> > > <victor.donascime...@arm.com> wrote:
> > > >
> > > > From: Victor Do Nascimento <vicdo...@e125768.arm.com>
> > > >
> > > > Given the novel treatment of the dot product optab as a conversion, we
> > > > are now able to targe different relationships between output modes and
> > > > input modes.
> > > >
> > > > This is made clearer by way of example. Previously, on AArch64, the
> > > > following loop was vectorizable:
> > > >
> > > > uint32_t udot4(int n, uint8_t* data) {
> > > > uint32_t sum = 0;
> > > > for (int i=0; i<n; i+=1)
> > > > sum += data[i] * data[i];
> > > > return sum;
> > > > }
> > > >
> > > > while the following was not:
> > > >
> > > > uint32_t udot2(int n, uint16_t* data) {
> > > > uint32_t sum = 0;
> > > > for (int i=0; i<n; i+=1)
> > > > sum += data[i] * data[i];
> > > > return sum;
> > > > }
> > > >
> > > > Under the new treatment of the dot product optab, they are both now
> > > > vectorizable.
> > > >
> > > > This adds the relevant target-agnostic check to ensure this behaviour
> > > > in the autovectorizer, gated behind the new check_effective_target
> > > > `vect_dotprod_twoway' as well a runtime check targetting aarch64.
> > >
> > > I think vect_dotprod_twoway is not clear - does aarch64 now support
> > > all of qi->hi, hi->si, si->di variants while formerly only "fourway"
> > > qi->si and hi->di?
> > >
> > > If it's just hi->si that's now supported please use vect_dotprod_hisi
> > > to be specific as to what is required/supported.
> >
> > At the moment we support only H->S, but other variants are being considered.
> > So perhaps vect_dotprod_single_step or something to make it clearer what it
> > does but still be general?
>
> But to be useful in the testsuite it has to be specific, not general.
Oh I see, you were talking specifically about the testsuite function and not the
optab itself. Yes, agreed. Sorry misunderstood!
Tamar
>
> > Thanks,
> > Tamar
> >
> > >
> > > Richard.
> > >
> > > > gcc/testsuite/ChangeLog:
> > > >
> > > > * lib/target-supports.exp
> (check_effective_target_vect_dotprod_twoway):
> > > > New.
> > > > * gcc.dg/vect/vect-dotprod-twoway.c: Likewise.
> > > > * gcc.target/aarch64/vect-dotprod-twoway.c: Likewise.
> > > > ---
> > > > .../gcc.dg/vect/vect-dotprod-twoway.c | 39 +++++++++++
> > > > .../gcc.target/aarch64/vect-dotprod-twoway.c | 65
> +++++++++++++++++++
> > > > gcc/testsuite/lib/target-supports.exp | 8 +++
> > > > 3 files changed, 112 insertions(+)
> > > > create mode 100644 gcc/testsuite/gcc.dg/vect/vect-dotprod-twoway.c
> > > > create mode 100644 gcc/testsuite/gcc.target/aarch64/vect-dotprod-
> twoway.c
> > > >
> > > > diff --git a/gcc/testsuite/gcc.dg/vect/vect-dotprod-twoway.c
> > > b/gcc/testsuite/gcc.dg/vect/vect-dotprod-twoway.c
> > > > new file mode 100644
> > > > index 00000000000..ff6a2559dee
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.dg/vect/vect-dotprod-twoway.c
> > > > @@ -0,0 +1,39 @@
> > > > +/* { dg-do compile } */
> > > > +/* { dg-require-effective-target vect_dotprod_twoway } */
> > > > +/* Ensure both the two-way and four-way dot products are
> > > > autovectorized.
> */
> > > > +#include <stdint.h>
> > > > +
> > > > +uint32_t udot4(int n, uint8_t* data) {
> > > > + uint32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +int32_t sdot4(int n, int8_t* data) {
> > > > + int32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +uint32_t udot2(int n, uint16_t* data) {
> > > > + uint32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +int32_t sdot2(int n, int16_t* data) {
> > > > + int32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 4 "vect" } }
> > > > */
> > > > +/* { dg-final { scan-tree-dump-times "vect_recog_dot_prod_pattern:
> detected"
> > > 4 "vect" } } */
> > > > diff --git a/gcc/testsuite/gcc.target/aarch64/vect-dotprod-twoway.c
> > > b/gcc/testsuite/gcc.target/aarch64/vect-dotprod-twoway.c
> > > > new file mode 100644
> > > > index 00000000000..bac1e1846da
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/aarch64/vect-dotprod-twoway.c
> > > > @@ -0,0 +1,65 @@
> > > > +/* { dg-do run } */
> > > > +/* { dg-require-effective-target vect_dotprod_twoway } */
> > > > +/* { dg-options "-march=armv8-a+sme2 -static -O3 -ftree-vectorize
> > > > -fdump-
> > > tree-vect-details -save-temps" } */
> > > > +/* Ensure runtime correctness in the autovectorized two-way dot product
> > > operations. */
> > > > +
> > > > +#include <stdint.h>
> > > > +#include <stdlib.h>
> > > > +
> > > > +uint32_t
> > > > +udot2 (int n, uint16_t* data) __arm_streaming
> > > > +{
> > > > + uint32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +int32_t
> > > > +sdot2 (int n, int16_t* data) __arm_streaming
> > > > +{
> > > > + int32_t sum = 0;
> > > > + for (int i=0; i<n; i+=1) {
> > > > + sum += data[i] * data[i];
> > > > + }
> > > > + return sum;
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > +
> > > > + uint16_t u_input_nil[] = { [0 ... 3] = 0 };
> > > > + uint16_t u_input_min[] = { [0 ... 3] = 1 };
> > > > + uint16_t u_input_max[] = { [0 ... 3] = 32767};
> > > > +
> > > > + uint32_t u_nil_dotprod = udot2 (4, u_input_nil);
> > > > + uint32_t u_min_dotprod = udot2 (4, u_input_min);
> > > > + uint32_t u_max_dotprod = udot2 (4, u_input_max);
> > > > +
> > > > + if (u_nil_dotprod != 0
> > > > + || u_min_dotprod != 4
> > > > + || u_max_dotprod != 4294705156)
> > > > + abort ();
> > > > +
> > > > + int16_t s_input_nil[] = { [0 ... 3] = 0 };
> > > > + int16_t s_input_min[] = { [0 ... 3] = -23170 };
> > > > + int16_t s_input_max[] = { [0 ... 3] = 23170 };
> > > > +
> > > > + int32_t s_nil_dotprod = sdot2 (4, s_input_nil);
> > > > + int32_t s_min_dotprod = sdot2 (4, s_input_min);
> > > > + int32_t s_max_dotprod = sdot2 (4, s_input_max);
> > > > +
> > > > + if (s_nil_dotprod != 0
> > > > + || s_min_dotprod != 2147395600
> > > > + || s_max_dotprod != 2147395600)
> > > > + abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" } }
> > > > */
> > > > +/* { dg-final { scan-tree-dump-times "vect_recog_dot_prod_pattern:
> detected"
> > > 46 "vect" } } */
> > > > +/* { dg-final { scan-assembler "\[ \t\]udot\tz\[0-9\]+.s, z\[0-9\]+.h,
> > > > z\[0-
> > > 9\]+.h" } } */
> > > > +/* { dg-final { scan-assembler "\[ \t\]sdot\tz\[0-9\]+.s, z\[0-9\]+.h,
> > > > z\[0-
> 9\]+.h"
> > > } } */
> > > > diff --git a/gcc/testsuite/lib/target-supports.exp
> > > > b/gcc/testsuite/lib/target-
> > > supports.exp
> > > > index 11ba77ca404..41618d399a3 100644
> > > > --- a/gcc/testsuite/lib/target-supports.exp
> > > > +++ b/gcc/testsuite/lib/target-supports.exp
> > > > @@ -4258,6 +4258,14 @@ proc check_effective_target_vect_int { } {
> > > > }}]
> > > > }
> > > >
> > > > +# Return 1 if the target supports two-way dot products, or 0 otherwise.
> > > > +
> > > > +proc check_effective_target_vect_dotprod_twoway { } {
> > > > + return [check_cached_effective_target_indexed aarch64_sme2 {
> > > > + expr { [check_effective_target_aarch64_sme2]
> > > > + }}]
> > > > +}
> > > > +
> > > > # Return 1 if the target supports vectorization of early breaks,
> > > > # 0 otherwise.
> > > > #
> > > > --
> > > > 2.34.1
> > > >
