Ping ^ 2: [PATCH] rs6000: Expand fmod and remainder when built with fast-math [PR97142]

[Xionghu Luo <luoxhu@linux.ibm.com>]

Gentle ping ^2, thanks.

https://gcc.gnu.org/pipermail/gcc-patches/2021-April/568143.html


On 2021/5/14 15:13, Xionghu Luo via Gcc-patches wrote:
> Test SPEC2017 Ofast P8LE for this patch : 511.povray_r +1.14%,
> 526.blender_r +1.72%, no obvious changes to others.
> 
> 
> On 2021/5/6 10:36, Xionghu Luo via Gcc-patches wrote:
>> Gentle ping, thanks.
>>
>>
>> On 2021/4/16 15:10, Xiong Hu Luo wrote:
>>> fmod/fmodf and remainder/remainderf could be expanded instead of library
>>> call when fast-math build, which is much faster.
>>>
>>> fmodf:
>>>       fdivs   f0,f1,f2
>>>       friz    f0,f0
>>>       fnmsubs f1,f2,f0,f1
>>>
>>> remainderf:
>>>       fdivs   f0,f1,f2
>>>       frin    f0,f0
>>>       fnmsubs f1,f2,f0,f1
>>>
>>> gcc/ChangeLog:
>>>
>>> 2021-04-16  Xionghu Luo  <luoxhu@linux.ibm.com>
>>>
>>>     PR target/97142
>>>     * config/rs6000/rs6000.md (fmod<mode>3): New define_expand.
>>>     (remainder<mode>3): Likewise.
>>>
>>> gcc/testsuite/ChangeLog:
>>>
>>> 2021-04-16  Xionghu Luo  <luoxhu@linux.ibm.com>
>>>
>>>     PR target/97142
>>>     * gcc.target/powerpc/pr97142.c: New test.
>>> ---
>>>   gcc/config/rs6000/rs6000.md                | 36 ++++++++++++++++++++++
>>>   gcc/testsuite/gcc.target/powerpc/pr97142.c | 30 ++++++++++++++++++
>>>   2 files changed, 66 insertions(+)
>>>   create mode 100644 gcc/testsuite/gcc.target/powerpc/pr97142.c
>>>
>>> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
>>> index a1315523fec..7e0e94e6ba4 100644
>>> --- a/gcc/config/rs6000/rs6000.md
>>> +++ b/gcc/config/rs6000/rs6000.md
>>> @@ -4902,6 +4902,42 @@ (define_insn "fre<sd>"
>>>     [(set_attr "type" "fp")
>>>      (set_attr "isa" "*,<Fisa>")])
>>> +(define_expand "fmod<mode>3"
>>> +  [(use (match_operand:SFDF 0 "gpc_reg_operand"))
>>> +    (use (match_operand:SFDF 1 "gpc_reg_operand"))
>>> +    (use (match_operand:SFDF 2 "gpc_reg_operand"))]
>>> +  "TARGET_HARD_FLOAT
>>> +  && TARGET_FPRND
>>> +  && flag_unsafe_math_optimizations"
>>> +{
>>> +  rtx div = gen_reg_rtx (<MODE>mode);
>>> +  emit_insn (gen_div<mode>3 (div, operands[1], operands[2]));
>>> +
>>> +  rtx friz = gen_reg_rtx (<MODE>mode);
>>> +  emit_insn (gen_btrunc<mode>2 (friz, div));
>>> +
>>> +  emit_insn (gen_nfms<mode>4 (operands[0], operands[2], friz, 
>>> operands[1]));
>>> +  DONE;
>>> + })
>>> +
>>> +(define_expand "remainder<mode>3"
>>> +  [(use (match_operand:SFDF 0 "gpc_reg_operand"))
>>> +    (use (match_operand:SFDF 1 "gpc_reg_operand"))
>>> +    (use (match_operand:SFDF 2 "gpc_reg_operand"))]
>>> +  "TARGET_HARD_FLOAT
>>> +  && TARGET_FPRND
>>> +  && flag_unsafe_math_optimizations"
>>> +{
>>> +  rtx div = gen_reg_rtx (<MODE>mode);
>>> +  emit_insn (gen_div<mode>3 (div, operands[1], operands[2]));
>>> +
>>> +  rtx frin = gen_reg_rtx (<MODE>mode);
>>> +  emit_insn (gen_round<mode>2 (frin, div));
>>> +
>>> +  emit_insn (gen_nfms<mode>4 (operands[0], operands[2], frin, 
>>> operands[1]));
>>> +  DONE;
>>> + })
>>> +
>>>   (define_insn "*rsqrt<mode>2"
>>>     [(set (match_operand:SFDF 0 "gpc_reg_operand" "=<Ff>,wa")
>>>       (unspec:SFDF [(match_operand:SFDF 1 "gpc_reg_operand" "<Ff>,wa")]
>>> diff --git a/gcc/testsuite/gcc.target/powerpc/pr97142.c 
>>> b/gcc/testsuite/gcc.target/powerpc/pr97142.c
>>> new file mode 100644
>>> index 00000000000..48f25ca5b5b
>>> --- /dev/null
>>> +++ b/gcc/testsuite/gcc.target/powerpc/pr97142.c
>>> @@ -0,0 +1,30 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-Ofast" } */
>>> +
>>> +#include <math.h>
>>> +
>>> +float test1 (float x, float y)
>>> +{
>>> +  return fmodf (x, y);
>>> +}
>>> +
>>> +double test2 (double x, double y)
>>> +{
>>> +  return fmod (x, y);
>>> +}
>>> +
>>> +float test3 (float x, float y)
>>> +{
>>> +  return remainderf (x, y);
>>> +}
>>> +
>>> +double test4 (double x, double y)
>>> +{
>>> +  return remainder (x, y);
>>> +}
>>> +
>>> +/* { dg-final { scan-assembler-not {\mbl fmod\M} } } */
>>> +/* { dg-final { scan-assembler-not {\mbl fmodf\M} } } */
>>> +/* { dg-final { scan-assembler-not {\mbl remainder\M} } } */
>>> +/* { dg-final { scan-assembler-not {\mbl remainderf\M} } } */
>>> +
>>>
>>
> 

-- 
Thanks,
Xionghu