Re: [PATCH] [x86] Refine maskstore patterns with UNSPEC_MASKMOV.

[Hongtao Liu <crazylht@gmail.com>]

On Tue, Jun 27, 2023 at 3:20 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Tue, Jun 27, 2023 at 7:38 AM liuhongt <hongtao.liu@intel.com> wrote:
> >
> > At the rtl level, we cannot guarantee that the maskstore is not optimized
> > to other full-memory accesses, as the current implementations are equivalent
> > in terms of pattern, to solve this potential problem, this patch refines
> > the pattern of the maskstore and the intrinsics with unspec.
> >
> > One thing I'm not sure is VCOND_EXPR, should VCOND_EXPR also expect
> > fault suppression for masked-out elements?
>
> You mean the vcond and vcond_eq optabs?  No, those do not expect
> fault suppression.
Yes, vcond/vcond_eq, thanks for clarifying.
>
> >
> > Currently we're still using vec_merge for both AVX2 and AVX512 target.
> >
> > ------------------------
> > Similar like r14-2070-gc79476da46728e
> >
> > If mem_addr points to a memory region with less than whole vector size
> > bytes of accessible memory and k is a mask that would prevent reading
> > the inaccessible bytes from mem_addr, add UNSPEC_MASKMOV to prevent
> > it to be transformed to any other whole memory access instructions.
> >
> > Bootstrapped and regtested on x86_64-pc-linu-gnu{-m32,}.
> > Ready to push to trunk.
> >
> > gcc/ChangeLog:
> >
> >         PR rtl-optimization/110237
> >         * config/i386/sse.md (<avx512>_store<mode>_mask): Refine with
> >         UNSPEC_MASKMOV.
> >         (maskstore<mode><avx512fmaskmodelower): Ditto.
> >         (*<avx512>_store<mode>_mask): New define_insn, it's renamed
> >         from original <avx512>_store<mode>_mask.
> > ---
> >  gcc/config/i386/sse.md | 69 ++++++++++++++++++++++++++++++++++--------
> >  1 file changed, 57 insertions(+), 12 deletions(-)
> >
> > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> > index 3b50c7117f8..812cfca4b92 100644
> > --- a/gcc/config/i386/sse.md
> > +++ b/gcc/config/i386/sse.md
> > @@ -1608,7 +1608,7 @@ (define_insn "<avx512>_blendm<mode>"
> >     (set_attr "prefix" "evex")
> >     (set_attr "mode" "<sseinsnmode>")])
> >
> > -(define_insn "<avx512>_store<mode>_mask"
> > +(define_insn "*<avx512>_store<mode>_mask"
> >    [(set (match_operand:V48_AVX512VL 0 "memory_operand" "=m")
> >         (vec_merge:V48_AVX512VL
> >           (match_operand:V48_AVX512VL 1 "register_operand" "v")
> > @@ -1636,7 +1636,7 @@ (define_insn "<avx512>_store<mode>_mask"
> >     (set_attr "memory" "store")
> >     (set_attr "mode" "<sseinsnmode>")])
> >
> > -(define_insn "<avx512>_store<mode>_mask"
> > +(define_insn "*<avx512>_store<mode>_mask"
> >    [(set (match_operand:VI12HFBF_AVX512VL 0 "memory_operand" "=m")
> >         (vec_merge:VI12HFBF_AVX512VL
> >           (match_operand:VI12HFBF_AVX512VL 1 "register_operand" "v")
> > @@ -27008,21 +27008,66 @@ (define_expand "maskstore<mode><sseintvecmodelower>"
> >    "TARGET_AVX")
> >
> >  (define_expand "maskstore<mode><avx512fmaskmodelower>"
> > -  [(set (match_operand:V48H_AVX512VL 0 "memory_operand")
> > -       (vec_merge:V48H_AVX512VL
> > -         (match_operand:V48H_AVX512VL 1 "register_operand")
> > -         (match_dup 0)
> > -         (match_operand:<avx512fmaskmode> 2 "register_operand")))]
> > +  [(set (match_operand:V48_AVX512VL 0 "memory_operand")
> > +       (unspec:V48_AVX512VL
> > +         [(match_operand:V48_AVX512VL 1 "register_operand")
> > +          (match_dup 0)
> > +          (match_operand:<avx512fmaskmode> 2 "register_operand")]
> > +         UNSPEC_MASKMOV))]
> >    "TARGET_AVX512F")
> >
> >  (define_expand "maskstore<mode><avx512fmaskmodelower>"
> > -  [(set (match_operand:VI12_AVX512VL 0 "memory_operand")
> > -       (vec_merge:VI12_AVX512VL
> > -         (match_operand:VI12_AVX512VL 1 "register_operand")
> > -         (match_dup 0)
> > -         (match_operand:<avx512fmaskmode> 2 "register_operand")))]
> > +  [(set (match_operand:VI12HFBF_AVX512VL 0 "memory_operand")
> > +       (unspec:VI12HFBF_AVX512VL
> > +         [(match_operand:VI12HFBF_AVX512VL 1 "register_operand")
> > +          (match_dup 0)
> > +          (match_operand:<avx512fmaskmode> 2 "register_operand")]
> > +         UNSPEC_MASKMOV))]
> >    "TARGET_AVX512BW")
> >
> > +(define_insn "<avx512>_store<mode>_mask"
> > +  [(set (match_operand:V48_AVX512VL 0 "memory_operand" "=m")
> > +       (unspec:V48_AVX512VL
> > +         [(match_operand:V48_AVX512VL 1 "register_operand" "v")
> > +          (match_dup 0)
> > +          (match_operand:<avx512fmaskmode> 2 "register_operand" "Yk")]
> > +         UNSPEC_MASKMOV))]
> > +  "TARGET_AVX512F"
> > +{
> > +  if (FLOAT_MODE_P (GET_MODE_INNER (<MODE>mode)))
> > +    {
> > +      if (misaligned_operand (operands[0], <MODE>mode))
> > +       return "vmovu<ssemodesuffix>\t{%1, %0%{%2%}|%0%{%2%}, %1}";
> > +      else
> > +       return "vmova<ssemodesuffix>\t{%1, %0%{%2%}|%0%{%2%}, %1}";
> > +    }
> > +  else
> > +    {
> > +      if (misaligned_operand (operands[0], <MODE>mode))
> > +       return "vmovdqu<ssescalarsize>\t{%1, %0%{%2%}|%0%{%2%}, %1}";
> > +      else
> > +       return "vmovdqa<ssescalarsize>\t{%1, %0%{%2%}|%0%{%2%}, %1}";
> > +    }
> > +}
> > +  [(set_attr "type" "ssemov")
> > +   (set_attr "prefix" "evex")
> > +   (set_attr "memory" "store")
> > +   (set_attr "mode" "<sseinsnmode>")])
> > +
> > +(define_insn "<avx512>_store<mode>_mask"
> > +  [(set (match_operand:VI12HFBF_AVX512VL 0 "memory_operand" "=m")
> > +       (unspec:VI12HFBF_AVX512VL
> > +         [(match_operand:VI12HFBF_AVX512VL 1 "register_operand" "v")
> > +          (match_dup 0)
> > +          (match_operand:<avx512fmaskmode> 2 "register_operand" "Yk")]
> > +          UNSPEC_MASKMOV))]
> > +  "TARGET_AVX512BW"
> > +  "vmovdqu<ssescalarsize>\t{%1, %0%{%2%}|%0%{%2%}, %1}"
> > +  [(set_attr "type" "ssemov")
> > +   (set_attr "prefix" "evex")
> > +   (set_attr "memory" "store")
> > +   (set_attr "mode" "<sseinsnmode>")])
> > +
> >  (define_expand "cbranch<mode>4"
> >    [(set (reg:CC FLAGS_REG)
> >         (compare:CC (match_operand:VI48_AVX 1 "register_operand")
> > --
> > 2.39.1.388.g2fc9e9ca3c
> >



-- 
BR,
Hongtao