On Thu, Jun 30, 2022 at 10:45 AM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Thu, Jun 30, 2022 at 9:41 AM Uros Bizjak <ubiz...@gmail.com> wrote:
> >
> > On Thu, Jun 30, 2022 at 9:24 AM Jiang, Haochen <haochen.ji...@intel.com>
> > wrote:
> > >
> > > > -----Original Message-----
> > > > From: Uros Bizjak <ubiz...@gmail.com>
> > > > Sent: Thursday, June 30, 2022 2:20 PM
> > > > To: Jiang, Haochen <haochen.ji...@intel.com>
> > > > Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao....@intel.com>
> > > > Subject: Re: [PATCH] i386: Extend cvtps2pd to memory
> > > >
> > > > On Thu, Jun 30, 2022 at 7:59 AM Haochen Jiang <haochen.ji...@intel.com>
> > > > wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > > This patch aims to fix the cvtps2pd insn, which should also work on
> > > > > memory operand but currently does not. After this fix, when loop == 2,
> > > > > it will eliminate movq instruction.
> > > > >
> > > > > Regtested on x86_64-pc-linux-gnu. Ok for trunk?
> > > > >
> > > > > BRs,
> > > > > Haochen
> > > > >
> > > > > gcc/ChangeLog:
> > > > >
> > > > > PR target/43618
> > > > > * config/i386/sse.md (extendv2sfv2df2): New define_expand.
> > > > > (sse2_cvtps2pd_load<mask_name>): Rename extendvsdfv2df2.
>
> Rename FROM ...
>
> Please also mention change to sse2_cvtps2pd<mask_name>.
>
> > > > >
> > > > > gcc/testsuite/ChangeLog:
> > > > >
> > > > > PR target/43618
> > > > > * gcc.target/i386/pr43618-1.c: New test.
> > > >
> > > > This patch could be as simple as:
> > > >
> > > > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md index
> > > > 8cd0f617bf3..c331445cb2d 100644
> > > > --- a/gcc/config/i386/sse.md
> > > > +++ b/gcc/config/i386/sse.md
> > > > @@ -9195,7 +9195,7 @@
> > > > (define_insn "extendv2sfv2df2"
> > > > [(set (match_operand:V2DF 0 "register_operand" "=v")
> > > > (float_extend:V2DF
> > > > - (match_operand:V2SF 1 "register_operand" "v")))]
> > > > + (match_operand:V2SF 1 "nonimmediate_operand" "vm")))]
> > > > "TARGET_MMX_WITH_SSE"
> > > > "%vcvtps2pd\t{%1, %0|%0, %1}"
> > > > [(set_attr "type" "ssecvt")
> > >
> > > We also tested on this version, it is ok.
> > >
> > > The reason why the patch looks like this is because in the previous insn
> > > sse2_cvtps2pd<mask_name>, the constraint vm and vector_operand
> > > actually does not match the actual instruction. Memory operand is V2SF,
> > > not V4SF.
> > >
> > > Therefore, we changed the constraint in that insn. Then it caused another
> > > issue.
> > > For memory operand, it seems that we cannot generate those mask
> > > instructions.
> > > So I change the pattern to how extendv2hfv2df2 works.
> >
> > If you want to change the memory access in sse2_cvtps2pd<mask_name>,
> > then please see how e.g. <insn>v2hiv2di is handled in sse.md. In
> > addition to two instructions, you will need one define_insn_and_split
> > with a pre-reload splitter.
>
> Oh, nowadays combine does vec_select from a paradoxical subreg on its own.
>
> +(define_expand "extendv2sfv2df2"
> + [(set (match_operand:V2DF 0 "register_operand")
> + (float_extend:V2DF
> + (match_operand:V2SF 1 "nonimmediate_operand")))]
> + "TARGET_MMX_WITH_SSE"
> +{
> + if (!MEM_P (operands[1]))
> + {
>
> You will need force reg here:
>
> rtx op1 = force_reg (V2SFmode, operands[1]);
> + operands[1] = lowpart_subreg (V4SFmode, op1, V2SFmode);
> + emit_insn (gen_sse2_cvtps2pd (operands[0], operands[1]));
> + DONE;
> + }
> +})
>
>
> -(define_insn "extendv2sfv2df2"
> +(define_insn "sse2_cvtps2pd_load<mask_name>"
>
> Please name this insn "*sse2_cvtps2pd<mask_name>_1". Please note the
> star at the beginning, You don't have to make the name public.
>
> OK with the above changes.
Forgot to mention:
- (match_operand:V2SF 1 "register_operand" "v")))]
- "TARGET_MMX_WITH_SSE"
- "%vcvtps2pd\t{%1, %0|%0, %1}"
+ (match_operand:V2SF 1 "memory_operand" "m")))]
+ "TARGET_MMX_WITH_SSE && <mask_avx512vl_condition>"
+ "%vcvtps2pd\t{%1, %0<mask_operand2>|%0<mask_oper
and2>, %q1}"
[(set_attr "type" "ssecvt")
The new insn does not need to be limited to TARGET_MMX_WITH_SSE, so we
can use TARGET_SSE2 here.
Which opens the question if the expander could also be TARGET_SSE2
only. There are no MMX registers involved in any of the patterns
anymore.
Uros.
>
> Thanks,
> Uros,
