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From: Richard Sandiford <richard.sandiford@arm.com>
To: Tamar Christina <tamar.christina@arm.com>
Cc: gcc-patches@gcc.gnu.org,  nd@arm.com,  Richard.Earnshaw@arm.com,
	 Marcus.Shawcroft@arm.com,  Kyrylo.Tkachov@arm.com
Subject: Re: [PATCH 8/8]AArch64: Have reload not choose to do add on the scalar side if both values exist on the SIMD side.
Date: Tue, 01 Nov 2022 15:04:55 +0000	[thread overview]
Message-ID: <mpt7d0evhpk.fsf@arm.com> (raw)
In-Reply-To: <Y1+41nrRB4ZMXZZA@arm.com> (Tamar Christina's message of "Mon, 31 Oct 2022 12:00:22 +0000")

Tamar Christina <tamar.christina@arm.com> writes:
> Hi All,
>
> Currently we often times generate an r -> r add even if it means we need two
> reloads to perform it, i.e. in the case that the values are on the SIMD side.
>
> The pairwise operations expose these more now and so we get suboptimal codegen.
>
> Normally I would have liked to use ^ or $ here, but while this works for the
> simple examples, reload inexplicably falls apart on examples that should have
> been trivial. It forces a move to r -> w to use the w ADD, which is counter to
> what ^ and $ should do.
>
> However ! seems to fix all the regression and still maintains the good codegen.
>
> I have tried looking into whether it's our costings that are off, but I can't
> seem anything logical here.  So I'd like to push this change instead along with
> test that augment the other testcases that guard the r -> r variants.

This feels like a hack though.  r<-r+r is one of the simplest thing
the processor can do, so I don't think it makes logical sense to mark
it with !, which means "prohibitively expensive".  It's likely to
push operations that require reloads onto the SIMD side.

Thanks,
Richard

> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
>
> Ok for master?
>
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> 	* config/aarch64/aarch64.md (*add<mode>3_aarch64): Add ! to the r -> r
> 	alternative.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/aarch64/simd/scalar_addp.c: New test.
> 	* gcc.target/aarch64/simd/scalar_faddp.c: New test.
> 	* gcc.target/aarch64/simd/scalar_faddp2.c: New test.
> 	* gcc.target/aarch64/simd/scalar_fmaxp.c: New test.
> 	* gcc.target/aarch64/simd/scalar_fminp.c: New test.
> 	* gcc.target/aarch64/simd/scalar_maxp.c: New test.
> 	* gcc.target/aarch64/simd/scalar_minp.c: New test.
>
> --- inline copy of patch -- 
> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> index 09ae1118371f82ca63146fceb953eb9e820d05a4..c333fb1f72725992bb304c560f1245a242d5192d 100644
> --- a/gcc/config/aarch64/aarch64.md
> +++ b/gcc/config/aarch64/aarch64.md
> @@ -2043,7 +2043,7 @@ (define_expand "add<mode>3"
>  
>  (define_insn "*add<mode>3_aarch64"
>    [(set
> -    (match_operand:GPI 0 "register_operand" "=rk,rk,w,rk,r,r,rk")
> +    (match_operand:GPI 0 "register_operand" "=rk,!rk,w,rk,r,r,rk")
>      (plus:GPI
>       (match_operand:GPI 1 "register_operand" "%rk,rk,w,rk,rk,0,rk")
>       (match_operand:GPI 2 "aarch64_pluslong_operand" "I,r,w,J,Uaa,Uai,Uav")))]
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_addp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_addp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..5b8d40f19884fc7b4e7decd80758bc36fa76d058
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_addp.c
> @@ -0,0 +1,70 @@
> +/* { dg-do assemble } */
> +/* { dg-additional-options "-save-temps -O1 -std=c99" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef long long v2di __attribute__((vector_size (16)));
> +typedef unsigned long long v2udi __attribute__((vector_size (16)));
> +typedef int v2si __attribute__((vector_size (16)));
> +typedef unsigned int v2usi __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	addp	d0, v0.2d
> +** 	fmov	x0, d0
> +** 	ret
> +*/
> +long long
> +foo (v2di x)
> +{
> +  return x[1] + x[0];
> +}
> +
> +/*
> +** foo1:
> +** 	saddlp	v0.1d, v0.2s
> +** 	fmov	x0, d0
> +** 	ret
> +*/
> +long long
> +foo1 (v2si x)
> +{
> +  return x[1] + x[0];
> +}
> +
> +/*
> +** foo2:
> +** 	uaddlp	v0.1d, v0.2s
> +** 	fmov	x0, d0
> +** 	ret
> +*/
> +unsigned long long
> +foo2 (v2usi x)
> +{
> +  return x[1] + x[0];
> +}
> +
> +/*
> +** foo3:
> +** 	uaddlp	v0.1d, v0.2s
> +** 	add	d0, d0, d1
> +** 	fmov	x0, d0
> +** 	ret
> +*/
> +unsigned long long
> +foo3 (v2usi x, v2udi y)
> +{
> +  return (x[1] + x[0]) + y[0];
> +}
> +
> +/*
> +** foo4:
> +** 	saddlp	v0.1d, v0.2s
> +** 	add	d0, d0, d1
> +** 	fmov	x0, d0
> +** 	ret
> +*/
> +long long
> +foo4 (v2si x, v2di y)
> +{
> +  return (x[1] + x[0]) + y[0];
> +}
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..ff455e060fc833b2f63e89c467b91a76fbe31aff
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp.c
> @@ -0,0 +1,66 @@
> +/* { dg-do assemble } */
> +/* { dg-require-effective-target arm_v8_2a_fp16_scalar_ok } */
> +/* { dg-add-options arm_v8_2a_fp16_scalar } */
> +/* { dg-additional-options "-save-temps -O1" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef double v2df __attribute__((vector_size (16)));
> +typedef float v4sf __attribute__((vector_size (16)));
> +typedef __fp16 v8hf __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	faddp	d0, v0.2d
> +** 	ret
> +*/
> +double
> +foo (v2df x)
> +{
> +  return x[1] + x[0];
> +}
> +
> +/*
> +** foo1:
> +** 	faddp	s0, v0.2s
> +** 	ret
> +*/
> +float
> +foo1 (v4sf x)
> +{
> +  return x[0] + x[1];
> +}
> +
> +/*
> +** foo2:
> +** 	faddp	h0, v0.2h
> +** 	ret
> +*/
> +__fp16
> +foo2 (v8hf x)
> +{
> +  return x[0] + x[1];
> +}
> +
> +/*
> +** foo3:
> +** 	ext	v0.16b, v0.16b, v0.16b, #4
> +** 	faddp	s0, v0.2s
> +** 	ret
> +*/
> +float
> +foo3 (v4sf x)
> +{
> +  return x[1] + x[2];
> +}
> +
> +/*
> +** foo4:
> +** 	dup	s0, v0.s\[3\]
> +** 	faddp	h0, v0.2h
> +** 	ret
> +*/
> +__fp16
> +foo4 (v8hf x)
> +{
> +  return x[6] + x[7];
> +}
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp2.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp2.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..04412c3b45c51648e46ff20f730b1213e940391a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_faddp2.c
> @@ -0,0 +1,14 @@
> +/* { dg-do assemble } */
> +/* { dg-additional-options "-save-temps -O1 -w" } */
> +
> +typedef __m128i __attribute__((__vector_size__(2 * sizeof(long))));
> +double a[];
> +*b;
> +fn1() {
> +  __m128i c;
> +  *(__m128i *)a = c;
> +  *b = a[0] + a[1];
> +}
> +
> +/* { dg-final { scan-assembler-times {faddp\td0, v0\.2d} 1 } } */
> +
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_fmaxp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_fmaxp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..aa1d2bf17cd707b74d8f7c574506610ab4fd7299
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_fmaxp.c
> @@ -0,0 +1,56 @@
> +/* { dg-do assemble } */
> +/* { dg-require-effective-target arm_v8_2a_fp16_scalar_ok } */
> +/* { dg-add-options arm_v8_2a_fp16_scalar } */
> +/* { dg-additional-options "-save-temps -O1" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef double v2df __attribute__((vector_size (16)));
> +typedef float v4sf __attribute__((vector_size (16)));
> +typedef __fp16 v8hf __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	fmaxnmp	d0, v0.2d
> +** 	ret
> +*/
> +double
> +foo (v2df x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo1:
> +** 	fmaxnmp	s0, v0.2s
> +** 	ret
> +*/
> +float
> +foo1 (v4sf x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/*
> +** foo2:
> +** 	fmaxnmp	h0, v0.2h
> +** 	ret
> +*/
> +__fp16
> +foo2 (v8hf x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo3:
> +** 	fmaxnmp	s0, v0.2s
> +** 	fcvt	d0, s0
> +** 	fadd	d0, d0, d1
> +** 	ret
> +*/
> +double
> +foo3 (v4sf x, v2df y)
> +{
> +  return (x[0] > x[1] ? x[0] : x[1]) + y[0];
> +}
> +
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_fminp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_fminp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..6136c5272069c4d86f09951cdff25f1494e839f0
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_fminp.c
> @@ -0,0 +1,55 @@
> +/* { dg-do assemble } */
> +/* { dg-require-effective-target arm_v8_2a_fp16_scalar_ok } */
> +/* { dg-add-options arm_v8_2a_fp16_scalar } */
> +/* { dg-additional-options "-save-temps -O1" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef double v2df __attribute__((vector_size (16)));
> +typedef float v4sf __attribute__((vector_size (16)));
> +typedef __fp16 v8hf __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	fminnmp	d0, v0.2d
> +** 	ret
> +*/
> +double
> +foo (v2df x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo1:
> +** 	fminnmp	s0, v0.2s
> +** 	ret
> +*/
> +float
> +foo1 (v4sf x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo2:
> +** 	fminnmp	h0, v0.2h
> +** 	ret
> +*/
> +__fp16
> +foo2 (v8hf x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo3:
> +** 	fminnmp	s0, v0.2s
> +** 	fcvt	d0, s0
> +** 	fadd	d0, d0, d1
> +** 	ret
> +*/
> +double
> +foo3 (v4sf x, v2df y)
> +{
> +  return (x[0] < x[1] ? x[0] : x[1]) + y[0];
> +}
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_maxp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_maxp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..e219a13abc745b83dca58633fd2d812e276d6b2d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_maxp.c
> @@ -0,0 +1,74 @@
> +/* { dg-do assemble } */
> +/* { dg-additional-options "-save-temps -O1 -std=c99" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef long long v2di __attribute__((vector_size (16)));
> +typedef unsigned long long v2udi __attribute__((vector_size (16)));
> +typedef int v2si __attribute__((vector_size (16)));
> +typedef unsigned int v2usi __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	umov	x0, v0.d\[1\]
> +** 	fmov	x1, d0
> +** 	cmp	x0, x1
> +** 	csel	x0, x0, x1, ge
> +** 	ret
> +*/
> +long long
> +foo (v2di x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo1:
> +** 	smaxp	v0.2s, v0.2s, v0.2s
> +** 	smov	x0, v0.s\[0\]
> +** 	ret
> +*/
> +long long
> +foo1 (v2si x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo2:
> +** 	umaxp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	ret
> +*/
> +unsigned long long
> +foo2 (v2usi x)
> +{
> +  return x[0] > x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo3:
> +** 	umaxp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	fmov	x1, d1
> +** 	add	x0, x1, w0, uxtw
> +** 	ret
> +*/
> +unsigned long long
> +foo3 (v2usi x, v2udi y)
> +{
> +  return (x[0] > x[1] ? x[0] : x[1]) + y[0];
> +}
> +
> +/* 
> +** foo4:
> +** 	smaxp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	fmov	x1, d1
> +** 	add	x0, x1, w0, sxtw
> +** 	ret
> +*/
> +long long
> +foo4 (v2si x, v2di y)
> +{
> +  return (x[0] > x[1] ? x[0] : x[1]) + y[0];
> +}
> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/scalar_minp.c b/gcc/testsuite/gcc.target/aarch64/simd/scalar_minp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..2a32fb4ea3edaa4c547a7a481c3ddca6b477430e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/simd/scalar_minp.c
> @@ -0,0 +1,74 @@
> +/* { dg-do assemble } */
> +/* { dg-additional-options "-save-temps -O1 -std=c99" } */
> +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } } */
> +
> +typedef long long v2di __attribute__((vector_size (16)));
> +typedef unsigned long long v2udi __attribute__((vector_size (16)));
> +typedef int v2si __attribute__((vector_size (16)));
> +typedef unsigned int v2usi __attribute__((vector_size (16)));
> +
> +/*
> +** foo:
> +** 	umov	x0, v0.d\[1\]
> +** 	fmov	x1, d0
> +** 	cmp	x0, x1
> +** 	csel	x0, x0, x1, le
> +** 	ret
> +*/
> +long long
> +foo (v2di x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo1:
> +** 	sminp	v0.2s, v0.2s, v0.2s
> +** 	smov	x0, v0.s\[0\]
> +** 	ret
> +*/
> +long long
> +foo1 (v2si x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo2:
> +** 	uminp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	ret
> +*/
> +unsigned long long
> +foo2 (v2usi x)
> +{
> +  return x[0] < x[1] ? x[0] : x[1];
> +}
> +
> +/* 
> +** foo3:
> +** 	uminp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	fmov	x1, d1
> +** 	add	x0, x1, w0, uxtw
> +** 	ret
> +*/
> +unsigned long long
> +foo3 (v2usi x, v2udi y)
> +{
> +  return (x[0] < x[1] ? x[0] : x[1]) + y[0];
> +}
> +
> +/* 
> +** foo4:
> +** 	sminp	v0.2s, v0.2s, v0.2s
> +** 	fmov	w0, s0
> +** 	fmov	x1, d1
> +** 	add	x0, x1, w0, sxtw
> +** 	ret
> +*/
> +long long
> +foo4 (v2si x, v2di y)
> +{
> +  return (x[0] < x[1] ? x[0] : x[1]) + y[0];
> +}

  reply	other threads:[~2022-11-01 15:04 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-31 11:56 [PATCH 1/8]middle-end: Recognize scalar reductions from bitfields and array_refs Tamar Christina
2022-10-31 11:57 ` [PATCH 2/8]middle-end: Recognize scalar widening reductions Tamar Christina
2022-10-31 21:42   ` Jeff Law
2022-11-07 13:21   ` Richard Biener
2022-10-31 11:57 ` [PATCH 3/8]middle-end: Support extractions of subvectors from arbitrary element position inside a vector Tamar Christina
2022-10-31 21:44   ` Jeff Law
2022-11-01 14:25   ` Richard Sandiford
2022-11-11 14:33     ` Tamar Christina
2022-11-15  8:35       ` Hongtao Liu
2022-11-15  8:51         ` Tamar Christina
2022-11-15  9:37           ` Hongtao Liu
2022-11-15 10:00             ` Tamar Christina
2022-11-15 17:39               ` Richard Sandiford
2022-11-17  8:04                 ` Hongtao Liu
2022-11-17  9:39                   ` Richard Sandiford
2022-11-17 10:20                     ` Hongtao Liu
2022-11-17 13:59                       ` Richard Sandiford
2022-11-18  2:31                         ` Hongtao Liu
2022-11-18  9:16                           ` Richard Sandiford
2022-10-31 11:58 ` [PATCH 4/8]AArch64 aarch64: Implement widening reduction patterns Tamar Christina
2022-11-01 14:41   ` Richard Sandiford
2022-10-31 11:58 ` [PATCH 5/8]AArch64 aarch64: Make existing V2HF be usable Tamar Christina
2022-11-01 14:58   ` Richard Sandiford
2022-11-01 15:11     ` Tamar Christina
2022-11-11 14:39     ` Tamar Christina
2022-11-22 16:01       ` Tamar Christina
2022-11-30  4:26         ` Tamar Christina
2022-12-06 10:28       ` Richard Sandiford
2022-12-06 10:58         ` Tamar Christina
2022-12-06 11:05           ` Richard Sandiford
2022-10-31 11:59 ` [PATCH 6/8]AArch64: Add peephole and scheduling logic for pairwise operations that appear late in RTL Tamar Christina
2022-10-31 11:59 ` [PATCH 7/8]AArch64: Consolidate zero and sign extension patterns and add missing ones Tamar Christina
2022-11-30  4:28   ` Tamar Christina
2022-12-06 15:59   ` Richard Sandiford
2022-10-31 12:00 ` [PATCH 8/8]AArch64: Have reload not choose to do add on the scalar side if both values exist on the SIMD side Tamar Christina
2022-11-01 15:04   ` Richard Sandiford [this message]
2022-11-01 15:20     ` Tamar Christina
2022-10-31 21:41 ` [PATCH 1/8]middle-end: Recognize scalar reductions from bitfields and array_refs Jeff Law
2022-11-05 11:32 ` Richard Biener
2022-11-07  7:16   ` Tamar Christina
2022-11-07 10:17     ` Richard Biener
2022-11-07 11:00       ` Tamar Christina
2022-11-07 11:22         ` Richard Biener
2022-11-07 11:56           ` Tamar Christina
2022-11-22 10:36             ` Richard Sandiford
2022-11-22 10:58               ` Richard Biener
2022-11-22 11:02                 ` Tamar Christina
2022-11-22 11:06                   ` Richard Sandiford
2022-11-22 11:08                     ` Richard Biener
2022-11-22 14:33                       ` Jeff Law

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