Richard Biener <rguent...@suse.de> writes:
> On Fri, 25 Oct 2019, Jiufu Guo wrote:
>
>> Hi,
>>
>> In PR88760, there are a few disscussion about improve or tune unroller for
>> targets. And we would agree to enable unroller for small loops at O2 first.
>> And we could see performance improvement(~10%) for below code:
>> ```
>> subroutine foo (i, i1, block)
>> integer :: i, i1
>> integer :: block(9, 9, 9)
>> block(i:9,1,i1) = block(i:9,1,i1) - 10
>> end subroutine foo
>>
>> ```
>> This kind of code occurs a few times in exchange2 benchmark.
>>
>> Similar C code:
>> ```
>> for (i = 0; i < n; i++)
>> arr[i] = arr[i] - 10;
>> ```
>>
>> On powerpc64le, for O2 , enable -funroll-loops and limit
>> PARAM_MAX_UNROLL_TIMES=2 and PARAM_MAX_UNROLLED_INSNS=20, we can see >2%
>> overall improvement for SPEC2017.
>
> Note the behavior with LTO will be surprising (and generally when
> functions are compiled with different -O level via the optimize
> attribute). It's a bad idea to base --param values on the value
> of a global optimization option that can be set per function
> (see PR92046).
Thanks Richard,
--param values are not save per function. If using different method to
compile and link (e.g. compiling with -O2 -flto, linking with -flto -O2
-funroll-loops --param xxx), compiling and linking would use different
--param value.
>
> A better patch would have been to adjust via the target hooks for
> unroll adjust.
Yeap. And in unroll adjust target hook, we can do fine tunning with more
heuristic thougths. I'm going to refine this way.
Thanks again.
Jiufu Guo
BR.
>
> Thanks,
> Richard.
>
>> This patch is only for rs6000 in which we see visible performance
>> improvement.
>>
>> Bootstrapped on powerpc64le, and cases are updated. Is this ok for trunk?
>>
>> Jiufu Guo
>> BR
>>
>>
>> gcc/
>> 2019-10-25 Jiufu Guo <guoji...@linux.ibm.com>
>>
>> PR tree-optimization/88760
>> * config/rs6000/rs6000-common.c (rs6000_option_optimization_table): for
>> O2, enable funroll-loops.
>> * config/rs6000/rs6000.c (rs6000_option_override_internal): if unroller
>> is enabled throught O2, set constrains to PARAM_MAX_UNROLL_TIMES=2 and
>> PARAM_MAX_UNROLLED_INSNS=20 for small loops.
>>
>> gcc.testsuite/
>> 2019-10-25 Jiufu Guo <guoji...@linux.ibm.com>
>>
>> PR tree-optimization/88760
>> * gcc.target/powerpc/small-loop-unroll.c: New test.
>> * c-c++-common/tsan/thread_leak2.c: Update test.
>> * gcc.dg/pr59643.c: Update test.
>> * gcc.target/powerpc/loop_align.c: Update test.
>> * gcc.target/powerpc/ppc-fma-1.c: Update test.
>> * gcc.target/powerpc/ppc-fma-2.c: Update test.
>> * gcc.target/powerpc/ppc-fma-3.c: Update test.
>> * gcc.target/powerpc/ppc-fma-4.c: Update test.
>> * gcc.target/powerpc/pr78604.c: Update test.
>>
>> ---
>> gcc/common/config/rs6000/rs6000-common.c | 1 +
>> gcc/config/rs6000/rs6000.c | 20
>> ++++++++++++++++++++
>> gcc/testsuite/c-c++-common/tsan/thread_leak2.c | 1 +
>> gcc/testsuite/gcc.dg/pr59643.c | 1 +
>> gcc/testsuite/gcc.target/powerpc/loop_align.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/pr78604.c | 2 +-
>> gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c | 13 +++++++++++++
>> 11 files changed, 42 insertions(+), 6 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
>>
>> diff --git a/gcc/common/config/rs6000/rs6000-common.c
>> b/gcc/common/config/rs6000/rs6000-common.c
>> index 4b0c205..b947196 100644
>> --- a/gcc/common/config/rs6000/rs6000-common.c
>> +++ b/gcc/common/config/rs6000/rs6000-common.c
>> @@ -35,6 +35,7 @@ static const struct default_options
>> rs6000_option_optimization_table[] =
>> { OPT_LEVELS_ALL, OPT_fsplit_wide_types_early, NULL, 1 },
>> /* Enable -fsched-pressure for first pass instruction scheduling. */
>> { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
>> + { OPT_LEVELS_2_PLUS, OPT_funroll_loops, NULL, 1 },
>> { OPT_LEVELS_NONE, 0, NULL, 0 }
>> };
>>
>> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
>> index a129137d..9a8ff9a 100644
>> --- a/gcc/config/rs6000/rs6000.c
>> +++ b/gcc/config/rs6000/rs6000.c
>> @@ -4540,6 +4540,26 @@ rs6000_option_override_internal (bool global_init_p)
>> global_options.x_param_values,
>> global_options_set.x_param_values);
>>
>> + /* unroll very small loops 2 time if no -funroll-loops. */
>> + if (!global_options_set.x_flag_unroll_loops
>> + && !global_options_set.x_flag_unroll_all_loops)
>> + {
>> + maybe_set_param_value (PARAM_MAX_UNROLL_TIMES, 2,
>> + global_options.x_param_values,
>> + global_options_set.x_param_values);
>> +
>> + maybe_set_param_value (PARAM_MAX_UNROLLED_INSNS, 20,
>> + global_options.x_param_values,
>> + global_options_set.x_param_values);
>> +
>> + /* If fweb or frename-registers are not specificed in command-line,
>> + do not turn them on implicitly. */
>> + if (!global_options_set.x_flag_web)
>> + global_options.x_flag_web = 0;
>> + if (!global_options_set.x_flag_rename_registers)
>> + global_options.x_flag_rename_registers = 0;
>> + }
>> +
>> /* If using typedef char *va_list, signal that
>> __builtin_va_start (&ap, 0) can be optimized to
>> ap = __builtin_next_arg (0). */
>> diff --git a/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
>> b/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
>> index c9b8046..17aa5c6 100644
>> --- a/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
>> +++ b/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
>> @@ -1,4 +1,5 @@
>> /* { dg-shouldfail "tsan" } */
>> +/* { dg-additional-options "-fno-unroll-loops" { target { powerpc-*-*
>> powerpc64-*-* powerpc64le-*-* } } } */
>>
>> #include <pthread.h>
>> #include <unistd.h>
>> diff --git a/gcc/testsuite/gcc.dg/pr59643.c b/gcc/testsuite/gcc.dg/pr59643.c
>> index de78d60..3aef439 100644
>> --- a/gcc/testsuite/gcc.dg/pr59643.c
>> +++ b/gcc/testsuite/gcc.dg/pr59643.c
>> @@ -1,6 +1,7 @@
>> /* PR tree-optimization/59643 */
>> /* { dg-do compile } */
>> /* { dg-options "-O3 -fdump-tree-pcom-details" } */
>> +/* { dg-additional-options "-fno-unroll-loops" { target { powerpc-*-*
>> powerpc64-*-* powerpc64le-*-* } } } */
>>
>> void
>> foo (double *a, double *b, double *c, double d, double e, int n)
>> diff --git a/gcc/testsuite/gcc.target/powerpc/loop_align.c
>> b/gcc/testsuite/gcc.target/powerpc/loop_align.c
>> index ebe3782..ef67f77 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/loop_align.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/loop_align.c
>> @@ -1,6 +1,6 @@
>> /* { dg-do compile { target { powerpc*-*-* } } } */
>> /* { dg-skip-if "" { powerpc*-*-darwin* powerpc-ibm-aix* } } */
>> -/* { dg-options "-O2 -mdejagnu-cpu=power7 -falign-functions=16" } */
>> +/* { dg-options "-O2 -mdejagnu-cpu=power7 -falign-functions=16
>> -fno-unroll-loops" } */
>> /* { dg-final { scan-assembler ".p2align 5" } } */
>>
>> void f(double *a, double *b, double *c, unsigned long n) {
>> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
>> b/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
>> index b4945e6..2a5b92c 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
>> @@ -1,7 +1,7 @@
>> /* { dg-do compile { target { powerpc*-*-* } } } */
>> /* { dg-skip-if "" { powerpc*-*-darwin* } } */
>> /* { dg-require-effective-target powerpc_vsx_ok } */
>> -/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math" } */
>> +/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math
>> -fno-unroll-loops" } */
>> /* { dg-final { scan-assembler-times "xvmadd" 4 } } */
>> /* { dg-final { scan-assembler-times "xsmadd\|fmadd\ " 2 } } */
>> /* { dg-final { scan-assembler-times "fmadds" 2 } } */
>> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
>> b/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
>> index 5ed630a..bf2c67f 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
>> @@ -1,7 +1,7 @@
>> /* { dg-do compile { target { powerpc*-*-* } } } */
>> /* { dg-skip-if "" { powerpc*-*-darwin* } } */
>> /* { dg-require-effective-target powerpc_vsx_ok } */
>> -/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math
>> -ffp-contract=off" } */
>> +/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math
>> -ffp-contract=off -fno-unroll-loops" } */
>> /* { dg-final { scan-assembler-times "xvmadd" 2 } } */
>> /* { dg-final { scan-assembler-times "xsmadd\|fmadd\ " 1 } } */
>> /* { dg-final { scan-assembler-times "fmadds" 1 } } */
>> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
>> b/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
>> index ef252b3..8608116 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
>> @@ -2,7 +2,7 @@
>> /* { dg-skip-if "" { powerpc*-*-darwin* } } */
>> /* { dg-require-effective-target powerpc_altivec_ok } */
>> /* { dg-require-effective-target powerpc_fprs } */
>> -/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec
>> -ffast-math" } */
>> +/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec
>> -ffast-math -fno-unroll-loops" } */
>> /* { dg-final { scan-assembler-times "vmaddfp" 2 } } */
>> /* { dg-final { scan-assembler-times "fmadd " 2 } } */
>> /* { dg-final { scan-assembler-times "fmadds" 2 } } */
>> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
>> b/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
>> index c2eaf1a..291c2ee 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
>> @@ -2,7 +2,7 @@
>> /* { dg-skip-if "" { powerpc*-*-darwin* } } */
>> /* { dg-require-effective-target powerpc_altivec_ok } */
>> /* { dg-require-effective-target powerpc_fprs } */
>> -/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec
>> -ffast-math -ffp-contract=off" } */
>> +/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec
>> -ffast-math -ffp-contract=off -fno-unroll-loops" } */
>> /* { dg-final { scan-assembler-times "vmaddfp" 1 } } */
>> /* { dg-final { scan-assembler-times "fmadd " 1 } } */
>> /* { dg-final { scan-assembler-times "fmadds" 1 } } */
>> diff --git a/gcc/testsuite/gcc.target/powerpc/pr78604.c
>> b/gcc/testsuite/gcc.target/powerpc/pr78604.c
>> index 76d8945..35bfdb3 100644
>> --- a/gcc/testsuite/gcc.target/powerpc/pr78604.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/pr78604.c
>> @@ -1,7 +1,7 @@
>> /* { dg-do compile { target { powerpc*-*-* } } } */
>> /* { dg-skip-if "" { powerpc*-*-darwin* } } */
>> /* { dg-require-effective-target powerpc_p8vector_ok } */
>> -/* { dg-options "-mdejagnu-cpu=power8 -O2 -ftree-vectorize
>> -fdump-tree-vect-details" } */
>> +/* { dg-options "-mdejagnu-cpu=power8 -O2 -ftree-vectorize
>> -fdump-tree-vect-details -fno-unroll-loops" } */
>>
>> #ifndef SIZE
>> #define SIZE 1024
>> diff --git a/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
>> b/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
>> new file mode 100644
>> index 0000000..888ea50b
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
>> @@ -0,0 +1,13 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-O2 -fdump-rtl-loop2_unroll" } */
>> +
>> +void __attribute__ ((noinline)) foo(int n, int *arr)
>> +{
>> + int i;
>> + for (i = 0; i < n; i++)
>> + arr[i] = arr[i] - 10;
>> +}
>> +/* { dg-final { scan-rtl-dump-times "Unrolled loop 1 times" 1
>> "loop2_unroll" } } */
>> +/* { dg-final { scan-assembler-times "lwz" 3 } } */
>> +/* { dg-final { scan-assembler-times "stw" 3 } } */
>> +
>>
