On Thu, Jul 1, 2021 at 5:51 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Thu, Jul 1, 2021 at 9:20 AM liuhongt via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>
> How does this look on GIMPLE and why's it not better handled there?
Do you mean in match.pd, i'll try that.
C++ FE doesn't support _FLoat16, and the place float/double are
handled is in convert.c(which is GENERIC?), that's why I decided to do
it in the backend.
/* Disable until we figure out how to decide whether the functions are
present in runtime. */
/* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
if (optimize
&& (TYPE_MODE (type) == TYPE_MODE (double_type_node)
|| TYPE_MODE (type) == TYPE_MODE (float_type_node)))
>
> Richard.
>
> > gcc/ChangeLog:
> >
> > * config/i386/i386.md (*sqrthf2): New define_insn.
> > * config/i386/sse.md
> > (*avx512fp16_vmsqrthf2<mask_scalar_name><round_scalar_name>):
> > Ditto.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.target/i386/avx512fp16-builtin-sqrt-2.c: New test.
> > ---
> > gcc/config/i386/i386.md | 18 ++++++++++++++++++
> > gcc/config/i386/sse.md | 18 ++++++++++++++++++
> > .../i386/avx512fp16-builtin-sqrt-2.c | 18 ++++++++++++++++++
> > 3 files changed, 54 insertions(+)
> > create mode 100644
> > gcc/testsuite/gcc.target/i386/avx512fp16-builtin-sqrt-2.c
> >
> > diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> > index 5f45c4ff583..684b2080a93 100644
> > --- a/gcc/config/i386/i386.md
> > +++ b/gcc/config/i386/i386.md
> > @@ -16583,6 +16583,24 @@ (define_insn "*sqrt<mode>2_sse"
> > ]
> > (symbol_ref "true")))])
> >
> > +/* Optimize for code like (_Float16) __builtin_sqrtf ((float) f16)
> > + since it's not handled in frontend. */
> > +(define_insn "*sqrthf2"
> > + [(set (match_operand:HF 0 "register_operand" "=v,v")
> > + (float_truncate:HF
> > + (sqrt:MODEF
> > + (float_extend:MODEF
> > + (match_operand:HF 1 "nonimmediate_operand" "v,m")))))]
> > + "TARGET_AVX512FP16"
> > + "@
> > + vsqrtsh\t{%d1, %0|%0, %d1}
> > + vsqrtsh\t{%1, %d0|%d0, %1}"
> > + [(set_attr "type" "sse")
> > + (set_attr "atom_sse_attr" "sqrt")
> > + (set_attr "prefix" "evex")
> > + (set_attr "avx_partial_xmm_update" "false,true")
> > + (set_attr "mode" "HF")])
> > +
> > (define_expand "sqrthf2"
> > [(set (match_operand:HF 0 "register_operand")
> > (sqrt:HF
> > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> > index a76c30c75cb..f87f6893835 100644
> > --- a/gcc/config/i386/sse.md
> > +++ b/gcc/config/i386/sse.md
> > @@ -2407,6 +2407,24 @@ (define_insn
> > "*<sse>_vmsqrt<mode>2<mask_scalar_name><round_scalar_name>"
> > (set_attr "btver2_sse_attr" "sqrt")
> > (set_attr "mode" "<ssescalarmode>")])
> >
> > +(define_insn "*avx512fp16_vmsqrthf2<mask_scalar_name><round_scalar_name>"
> > + [(set (match_operand:V8HF 0 "register_operand" "=v")
> > + (vec_merge:V8HF
> > + (vec_duplicate:V8HF
> > + (float_truncate:HF
> > + (sqrt:MODEF
> > + (float_extend:MODEF
> > + (match_operand:HF 1 "nonimmediate_operand"
> > "<round_scalar_constraint>")))))
> > + (match_operand:VFH_128 2 "register_operand" "v")
> > + (const_int 1)))]
> > + "TARGET_AVX512FP16"
> > + "vsqrtsh\t{<round_scalar_mask_op3>%1, %2,
> > %0<mask_scalar_operand3>|%0<mask_scalar_operand3>, %2,
> > %1<round_scalar_mask_op3>}"
> > + [(set_attr "type" "sse")
> > + (set_attr "atom_sse_attr" "sqrt")
> > + (set_attr "prefix" "evex")
> > + (set_attr "mode" "HF")])
> > +
> > +
> > (define_expand "rsqrt<mode>2"
> > [(set (match_operand:VF1_AVX512ER_128_256 0 "register_operand")
> > (unspec:VF1_AVX512ER_128_256
> > diff --git a/gcc/testsuite/gcc.target/i386/avx512fp16-builtin-sqrt-2.c
> > b/gcc/testsuite/gcc.target/i386/avx512fp16-builtin-sqrt-2.c
> > new file mode 100644
> > index 00000000000..4fefee179af
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/avx512fp16-builtin-sqrt-2.c
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-Ofast -mavx512fp16" } */
> > +
> > +#include<math.h>
> > +_Float16
> > +foo (_Float16 f16)
> > +{
> > + return sqrtf (f16);
> > +}
> > +
> > +_Float16
> > +foo1 (_Float16 f16)
> > +{
> > + return sqrt (f16);
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "vcvtsh2s\[sd\]" } } */
> > +/* { dg-final { scan-assembler-times "vsqrtsh\[^\n\r\]*xmm\[0-9\]" 2 } } */
> > --
> > 2.18.1
> >
--
BR,
Hongtao
