Re: [PATCH] [tree-optimization] Optimize max/min pattern with comparison
On Tue, 1 Dec 2020, Eugene Rozenfeld via Gcc-patches wrote: Thank you for the review Jeff. I don't need to look at the opcode to know the result. The pattern will be matched only in these 4 cases: X <= MAX(X, Y) -> true X > MAX(X, Y) -> false X >= MIN(X, Y) -> true X < MIN(X, Y) -> false So, the result will be true for GE_EXPR and LE_EXPR and false otherwise. Is that true even if X is NaN? It may be hard to hit a situation where this matters though, if we honor NaN, we don't build MAX_EXPR (which is unspecified). -- Marc Glisse
Re: [PATCH] [tree-optimization] Optimize max/min pattern with comparison
On 11/30/20 7:00 PM, Eugene Rozenfeld wrote: > Thank you for the review Jeff. > > I don't need to look at the opcode to know the result. The pattern will be > matched only in these 4 cases: > > X <= MAX(X, Y) -> true > X > MAX(X, Y) -> false > X >= MIN(X, Y) -> true > X < MIN(X, Y) -> false > > So, the result will be true for GE_EXPR and LE_EXPR and false otherwise. > > I added two test files: one for positive cases and one for negative cases. > The updated patch is attached. Thanks. Installed. jeff
Re: [PATCH] [tree-optimization] Optimize max/min pattern with comparison
On 11/30/20 7:00 PM, Eugene Rozenfeld wrote: > Thank you for the review Jeff. > > I don't need to look at the opcode to know the result. The pattern will be > matched only in these 4 cases: > > X <= MAX(X, Y) -> true > X > MAX(X, Y) -> false > X >= MIN(X, Y) -> true > X < MIN(X, Y) -> false > > So, the result will be true for GE_EXPR and LE_EXPR and false otherwise. > > I added two test files: one for positive cases and one for negative cases. > The updated patch is attached. Nuts, they weren't nested FORs, sorry for mis-reading. I'll take another close look tomorrow. jeff
Re: [PATCH] [tree-optimization] Optimize max/min pattern with comparison
Thank you for the review Jeff.
I don't need to look at the opcode to know the result. The pattern will be
matched only in these 4 cases:
X <= MAX(X, Y) -> true
X > MAX(X, Y) -> false
X >= MIN(X, Y) -> true
X < MIN(X, Y) -> false
So, the result will be true for GE_EXPR and LE_EXPR and false otherwise.
I added two test files: one for positive cases and one for negative cases. The
updated patch is attached.
Thanks,
Eugene
-Original Message-
From: Jeff Law
Sent: Monday, November 30, 2020 9:51 AM
To: Eugene Rozenfeld ; gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] [tree-optimization] Optimize max/min pattern with
comparison
On 11/25/20 3:04 PM, Eugene Rozenfeld via Gcc-patches wrote:
> Make the following simplifications:
> X <= MAX(X, Y) -> true
> X > MAX(X, Y) -> false
> X >= MIN(X, Y) -> true
> X < MIN(X, Y) -> false
>
> This fixes PR96708.
>
> Tested on x86_64-pc-linux-gnu.
>
> bool f(int a, int b)
> {
> int tmp = (a < b) ? b : a;
> return tmp >= a;
> }
>
> Code without the patch:
>
> vmovd xmm0,edi
> vmovd xmm1,esi
> vpmaxsd xmm0,xmm0,xmm1
> vmovd eax,xmm0
> cmpeax,edi
> setge al
> ret
>
> Code with the patch:
>
> moveax,0x1
> ret
>
> Eugene
>
> 0001-Optimize-max-pattern-with-comparison.patch
>
> From f6391c197b670b516238ac7707512c1358336520 Mon Sep 17 00:00:00 2001
> From: Eugene Rozenfeld
> Date: Sat, 21 Nov 2020 01:08:50 -0800
> Subject: [PATCH] Optimize max pattern with comparison
>
> Make the following simplifications:
> X <= MAX(X, Y) -> true
> X > MAX(X, Y) -> false
> X >= MIN(X, Y) -> true
> X < MIN(X, Y) -> false
>
> This fixes PR96708.
>
> gcc/
> * match.pd : New patterns.
> ---
> gcc/match.pd | 10 ++
> 1 file changed, 10 insertions(+)
>
> diff --git a/gcc/match.pd b/gcc/match.pd index
> cbb4bf0b32d..75237741946 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -2851,6 +2851,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>(cmp (minmax @0 INTEGER_CST@1) INTEGER_CST@2)
>(comb (cmp @0 @2) (cmp @1 @2
>
> +/* X <= MAX(X, Y) -> true
> + X > MAX(X, Y) -> false
> + X >= MIN(X, Y) -> true
> + X < MIN(X, Y) -> false */
> +(for minmax (min min max max )
> + cmp(ge lt le gt )
> + (simplify
> + (cmp @0 (minmax:c @0 @1))
> + { constant_boolean_node (cmp == GE_EXPR || cmp == LE_EXPR, type); }
> +))
Don't you need to look at the opcode (MIN vs MAX) vs CMP to know the result?Â
I'd really like to see some tests for the testsuite.   In particular I'd
like to see positive tests where we should apply the optimization and negative
tests when we should not apply the optimization.
I also wonder if there's value in handling this in Ranger and/or DOM. Though
I'd probably wait to see if fixing in match.pd is sufficient to cover the cases
I'm thinking of in Ranger & DOM.
Jeff
0001-Optimize-min-and-max-patterns-with-comparison.patch
Description: 0001-Optimize-min-and-max-patterns-with-comparison.patch
Re: [PATCH] [tree-optimization] Optimize max/min pattern with comparison
On 11/25/20 3:04 PM, Eugene Rozenfeld via Gcc-patches wrote:
> Make the following simplifications:
> X <= MAX(X, Y) -> true
> X > MAX(X, Y) -> false
> X >= MIN(X, Y) -> true
> X < MIN(X, Y) -> false
>
> This fixes PR96708.
>
> Tested on x86_64-pc-linux-gnu.
>
> bool f(int a, int b)
> {
> int tmp = (a < b) ? b : a;
> return tmp >= a;
> }
>
> Code without the patch:
>
> vmovd xmm0,edi
> vmovd xmm1,esi
> vpmaxsd xmm0,xmm0,xmm1
> vmovd eax,xmm0
> cmpeax,edi
> setge al
> ret
>
> Code with the patch:
>
> moveax,0x1
> ret
>
> Eugene
>
> 0001-Optimize-max-pattern-with-comparison.patch
>
> From f6391c197b670b516238ac7707512c1358336520 Mon Sep 17 00:00:00 2001
> From: Eugene Rozenfeld
> Date: Sat, 21 Nov 2020 01:08:50 -0800
> Subject: [PATCH] Optimize max pattern with comparison
>
> Make the following simplifications:
> X <= MAX(X, Y) -> true
> X > MAX(X, Y) -> false
> X >= MIN(X, Y) -> true
> X < MIN(X, Y) -> false
>
> This fixes PR96708.
>
> gcc/
> * match.pd : New patterns.
> ---
> gcc/match.pd | 10 ++
> 1 file changed, 10 insertions(+)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index cbb4bf0b32d..75237741946 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -2851,6 +2851,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>(cmp (minmax @0 INTEGER_CST@1) INTEGER_CST@2)
>(comb (cmp @0 @2) (cmp @1 @2
>
> +/* X <= MAX(X, Y) -> true
> + X > MAX(X, Y) -> false
> + X >= MIN(X, Y) -> true
> + X < MIN(X, Y) -> false */
> +(for minmax (min min max max )
> + cmp(ge lt le gt )
> + (simplify
> + (cmp @0 (minmax:c @0 @1))
> + { constant_boolean_node (cmp == GE_EXPR || cmp == LE_EXPR, type); } ))
Don't you need to look at the opcode (MIN vs MAX) vs CMP to know the
result? I'd really like to see some tests for the testsuite.   In
particular I'd like to see positive tests where we should apply the
optimization and negative tests when we should not apply the optimization.
I also wonder if there's value in handling this in Ranger and/or DOM.Â
Though I'd probably wait to see if fixing in match.pd is sufficient to
cover the cases I'm thinking of in Ranger & DOM.
Jeff
[PATCH] [tree-optimization] Optimize max/min pattern with comparison
Make the following simplifications:
X <= MAX(X, Y) -> true
X > MAX(X, Y) -> false
X >= MIN(X, Y) -> true
X < MIN(X, Y) -> false
This fixes PR96708.
Tested on x86_64-pc-linux-gnu.
bool f(int a, int b)
{
int tmp = (a < b) ? b : a;
return tmp >= a;
}
Code without the patch:
vmovd xmm0,edi
vmovd xmm1,esi
vpmaxsd xmm0,xmm0,xmm1
vmovd eax,xmm0
cmpeax,edi
setge al
ret
Code with the patch:
moveax,0x1
ret
Eugene
0001-Optimize-max-pattern-with-comparison.patch
Description: 0001-Optimize-max-pattern-with-comparison.patch
