| Message ID | mptwnp2ab5j.fsf@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | vect: Tweak comparisons with existing epilogue loops | expand |
On Tue, Aug 3, 2021 at 3:52 PM Richard Sandiford via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > This patch uses a more accurate scalar iteration estimate when > comparing the epilogue of a constant-iteration loop with a candidate > replacement epilogue. > > In the testcase, the patch prevents a 1-to-3-element SVE epilogue > from seeming better than a 64-bit Advanced SIMD epilogue. > > Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install? OK. Richard. > Richard > > > gcc/ > * tree-vect-loop.c (vect_better_loop_vinfo_p): Detect cases in > which old_loop_vinfo is an epilogue loop that handles a constant > number of iterations. > > gcc/testsuite/ > * gcc.target/aarch64/sve/cost_model_12.c: New test. > --- > .../gcc.target/aarch64/sve/cost_model_12.c | 19 +++++++++++++++++++ > gcc/tree-vect-loop.c | 10 +++++++++- > 2 files changed, 28 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c > > diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c > index 0009d0964af..0a5b65adb04 100644 > --- a/gcc/tree-vect-loop.c > +++ b/gcc/tree-vect-loop.c > @@ -2778,7 +2778,15 @@ vect_better_loop_vinfo_p (loop_vec_info new_loop_vinfo, > > /* Limit the VFs to what is likely to be the maximum number of iterations, > to handle cases in which at least one loop_vinfo is fully-masked. */ > - HOST_WIDE_INT estimated_max_niter = likely_max_stmt_executions_int (loop); > + HOST_WIDE_INT estimated_max_niter; > + loop_vec_info main_loop = LOOP_VINFO_ORIG_LOOP_INFO (old_loop_vinfo); > + unsigned HOST_WIDE_INT main_vf; > + if (main_loop > + && LOOP_VINFO_NITERS_KNOWN_P (main_loop) > + && LOOP_VINFO_VECT_FACTOR (main_loop).is_constant (&main_vf)) > + estimated_max_niter = LOOP_VINFO_INT_NITERS (main_loop) % main_vf; > + else > + estimated_max_niter = likely_max_stmt_executions_int (loop); > if (estimated_max_niter != -1) > { > if (known_le (estimated_max_niter, new_vf)) > diff --git a/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c b/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c > new file mode 100644 > index 00000000000..4c5226e05de > --- /dev/null > +++ b/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c > @@ -0,0 +1,19 @@ > +/* { dg-options "-O3 -mtune=neoverse-512tvb" } */ > + > +void > +f (float x[restrict 10][1024], > + float y[restrict 10][1024], float z) > +{ > + for (int i = 0; i < 10; ++i) > + { > +#pragma GCC unroll 10 > + for (int j = 0; j < 10; ++j) > + x[j][i] = y[j][i] * z; > + } > +} > + > +/* We should unroll the outer loop, with 2x 16-byte vectors and 1x > + 8-byte vectors. */ > +/* { dg-final { scan-assembler-not {\tptrue\t} } } */ > +/* { dg-final { scan-assembler {\tv[0-9]+\.4s,} } } */ > +/* { dg-final { scan-assembler {\tv[0-9]+\.2s,} } } */
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 0009d0964af..0a5b65adb04 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -2778,7 +2778,15 @@ vect_better_loop_vinfo_p (loop_vec_info new_loop_vinfo, /* Limit the VFs to what is likely to be the maximum number of iterations, to handle cases in which at least one loop_vinfo is fully-masked. */ - HOST_WIDE_INT estimated_max_niter = likely_max_stmt_executions_int (loop); + HOST_WIDE_INT estimated_max_niter; + loop_vec_info main_loop = LOOP_VINFO_ORIG_LOOP_INFO (old_loop_vinfo); + unsigned HOST_WIDE_INT main_vf; + if (main_loop + && LOOP_VINFO_NITERS_KNOWN_P (main_loop) + && LOOP_VINFO_VECT_FACTOR (main_loop).is_constant (&main_vf)) + estimated_max_niter = LOOP_VINFO_INT_NITERS (main_loop) % main_vf; + else + estimated_max_niter = likely_max_stmt_executions_int (loop); if (estimated_max_niter != -1) { if (known_le (estimated_max_niter, new_vf)) diff --git a/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c b/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c new file mode 100644 index 00000000000..4c5226e05de --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/sve/cost_model_12.c @@ -0,0 +1,19 @@ +/* { dg-options "-O3 -mtune=neoverse-512tvb" } */ + +void +f (float x[restrict 10][1024], + float y[restrict 10][1024], float z) +{ + for (int i = 0; i < 10; ++i) + { +#pragma GCC unroll 10 + for (int j = 0; j < 10; ++j) + x[j][i] = y[j][i] * z; + } +} + +/* We should unroll the outer loop, with 2x 16-byte vectors and 1x + 8-byte vectors. */ +/* { dg-final { scan-assembler-not {\tptrue\t} } } */ +/* { dg-final { scan-assembler {\tv[0-9]+\.4s,} } } */ +/* { dg-final { scan-assembler {\tv[0-9]+\.2s,} } } */