Re: [PATCH] match.pd: Add new abs pattern [PR94290]

[Sam Feifer <sfeifer@redhat.com>]

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Here's an updated version of the patch.

Thanks
-Sam

On Thu, Jul 14, 2022 at 3:54 PM Andrew Pinski <pinskia@gmail.com> wrote:

> On Thu, Jul 14, 2022 at 12:38 PM Sam Feifer <sfeifer@redhat.com> wrote:
> >
> >
> >
> > On Thu, Jul 14, 2022 at 1:24 PM Andrew Pinski <pinskia@gmail.com> wrote:
> >>
> >> On Thu, Jul 14, 2022 at 7:09 AM Sam Feifer <sfeifer@redhat.com> wrote:
> >> >
> >> >
> >> > On Wed, Jul 13, 2022 at 3:36 PM Andrew Pinski <pinskia@gmail.com>
> wrote:
> >> >>
> >> >> On Wed, Jul 13, 2022 at 12:26 PM Sam Feifer via Gcc-patches
> >> >> <gcc-patches@gcc.gnu.org> wrote:
> >> >> >
> >> >> > This patch is intended to fix a missed optimization in match.pd.
> It optimizes (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) to just abs(x). I had to
> write a second simplification in match.pd to handle the commutative
> property as the match was not ocurring otherwise. Additionally, the pattern
> (x <= 0 ? -x : 0) now gets optimized to max(-x, 0), which helps with the
> other simplification rule.
> >> >>
> >> >> You could use :c for the commutative property instead and that should
> >> >> simplify things.
> >> >> That is:
> >> >>
> >> >> (simplify
> >> >>   (plus:c (max @0 integer_zerop) (max (negate @0) integer_zerop))
> >> >>   (abs @0))
> >> >>
> >> >> Also since integer_zerop works on vectors, it seems like you should
> >> >> add a testcase or two for the vector case.
> >> >> Also would be useful if you write a testcase that uses different
> >> >> statements rather than one big one so it gets exercised in the
> >> >> forwprop case.
> >> >> Note also if either of the max are used more than just in this
> >> >> simplification, it could increase the lifetime of @0, maybe you need
> >> >> to add :s to the max expressions.
> >> >>
> >> >
> >> > Thanks for the feedback. I'm not quite sure what a vector test case
> would look like for this. Could I get some guidance on that?
> >>
> >> Yes this should produce the pattern at forwprop1 time (with the C++
> >> front-end, the C front-end does not support vector selects):
> >> typedef int __attribute__((vector_size(4*sizeof(int)))) vint;
> >>
> >> vint foo(vint x) {
> >>     vint t = (x >= 0 ? x : 0) ;
> >>     vint xx = -x;
> >>     vint t1 =  (xx >= 0 ? xx : 0);
> >>     return t + t1;
> >> }
> >>
> >> int foo(int x) {
> >>     int t = (x >= 0 ? x : 0) ;
> >>     int xx = -x;
> >>     int t1 =  (xx >= 0 ? xx : 0);
> >>     return t + t1;
> >> }
> >>
> >> Thanks,
> >> Andrew Pinski
> >>
> >
> > Thanks for the help. I'm still having trouble with the vector test,
> though. When I try to compile, I get an error saying "used vector type
> where scalar is required", referring to the max expressions. How do I use
> the max expression with two vectors as the inputs?
>
> As I mentioned it only works with the C++ front-end :). The C
> front-end does not support ?: with vectors types.
>
> Thanks,
> Andrew Pinski
>
> >
> > Thanks
> > -Sam
> >>
> >>
> >> >
> >> > Thanks
> >> > -Sam
> >> >
> >> >>
> >> >> Thanks,
> >> >> Andrew
> >> >>
> >> >> >
> >> >> > Tests are also included to be added to the testsuite.
> >> >> >
> >> >> > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> >> >> >
> >> >> >         PR tree-optimization/94290
> >> >> >
> >> >> > gcc/ChangeLog:
> >> >> >
> >> >> >         * match.pd (x >= 0 ? x : 0) + (x <= 0 ? -x : 0): New
> simplification.
> >> >> >         * match.pd (x <= 0 ? -x : 0): New Simplification.
> >> >> >
> >> >> > gcc/testsuite/ChangeLog:
> >> >> >
> >> >> >         * gcc.c-torture/execute/pr94290-1.c: New test.
> >> >> >         * gcc.dg/pr94290-2.c: New test.
> >> >> >         * gcc.dg/pr94290.c: New test.
> >> >> > ---
> >> >> >  gcc/match.pd                                  | 15 ++++++
> >> >> >  .../gcc.c-torture/execute/pr94290-1.c         | 16 +++++++
> >> >> >  gcc/testsuite/gcc.dg/pr94290-2.c              | 15 ++++++
> >> >> >  gcc/testsuite/gcc.dg/pr94290.c                | 46
> +++++++++++++++++++
> >> >> >  4 files changed, 92 insertions(+)
> >> >> >  create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
> >> >> >  create mode 100644 gcc/testsuite/gcc.dg/pr94290-2.c
> >> >> >  create mode 100644 gcc/testsuite/gcc.dg/pr94290.c
> >> >> >
> >> >> > diff --git a/gcc/match.pd b/gcc/match.pd
> >> >> > index 45aefd96688..55ca79d7ac9 100644
> >> >> > --- a/gcc/match.pd
> >> >> > +++ b/gcc/match.pd
> >> >> > @@ -7848,3 +7848,18 @@ and,
> >> >> >        (if (TYPE_UNSIGNED (TREE_TYPE (@0)))
> >> >> >          (bit_and @0 @1)
> >> >> >        (cond (le @0 @1) @0 (bit_and @0 @1))))))
> >> >> > +
> >> >> > +/* (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) -> abs x.  */
> >> >> > +(simplify
> >> >> > +  (plus (max @0 integer_zerop) (max (negate @0) integer_zerop))
> >> >> > +  (abs @0))
> >> >> > +
> >> >> > +/* (x <= 0 ? -x : 0) + (x >= 0 ? x : 0) -> abs x.  */
> >> >> > +(simplify
> >> >> > +  (plus (max (negate @0) integer_zerop) (max @0 integer_zerop) )
> >> >> > +  (abs @0))
> >> >> > +
> >> >> > +/* (x <= 0 ? -x : 0) -> max(-x, 0).  */
> >> >> > +(simplify
> >> >> > + (cond (le @0 integer_zerop@1) (negate @0) integer_zerop@1)
> >> >> > + (max (negate @0) @1))
> >> >> > diff --git a/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
> b/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
> >> >> > new file mode 100644
> >> >> > index 00000000000..93b80d569aa
> >> >> > --- /dev/null
> >> >> > +++ b/gcc/testsuite/gcc.c-torture/execute/pr94290-1.c
> >> >> > @@ -0,0 +1,16 @@
> >> >> > +/* PR tree-optimization/94290 */
> >> >> > +
> >> >> > +#include "../../gcc.dg/pr94290.c"
> >> >> > +
> >> >> > +int main() {
> >> >> > +
> >> >> > +    if (foo(0) != 0
> >> >> > +        || foo(-42) != 42
> >> >> > +        || foo(42) != 42
> >> >> > +        || baz(-10) != 10
> >> >> > +        || baz(-10) != 10) {
> >> >> > +            __builtin_abort();
> >> >> > +        }
> >> >> > +
> >> >> > +    return 0;
> >> >> > +}
> >> >> > diff --git a/gcc/testsuite/gcc.dg/pr94290-2.c
> b/gcc/testsuite/gcc.dg/pr94290-2.c
> >> >> > new file mode 100644
> >> >> > index 00000000000..ea6e55755f5
> >> >> > --- /dev/null
> >> >> > +++ b/gcc/testsuite/gcc.dg/pr94290-2.c
> >> >> > @@ -0,0 +1,15 @@
> >> >> > +/* PR tree-optimization/94290 */
> >> >> > +/* { dg-do compile } */
> >> >> > +/* { dg-options "-O2 -fdump-tree-optimized" } */
> >> >> > +
> >> >> > +/* Form from PR.  */
> >> >> > +__attribute__((noipa)) unsigned int foo(int x) {
> >> >> > +    return x <= 0 ? -x : 0;
> >> >> > +}
> >> >> > +
> >> >> > +/* Changed order.  */
> >> >> > +__attribute__((noipa)) unsigned int bar(int x) {
> >> >> > +    return 0 >= x ? -x : 0;
> >> >> > +}
> >> >> > +
> >> >> > +/* { dg-final {scan-tree-dump-times " MAX_EXPR " 2 "optimized" }
> } */
> >> >> > diff --git a/gcc/testsuite/gcc.dg/pr94290.c
> b/gcc/testsuite/gcc.dg/pr94290.c
> >> >> > new file mode 100644
> >> >> > index 00000000000..47617c36c02
> >> >> > --- /dev/null
> >> >> > +++ b/gcc/testsuite/gcc.dg/pr94290.c
> >> >> > @@ -0,0 +1,46 @@
> >> >> > +/* PR tree-optimization/94290 */
> >> >> > +/* { dg-do compile } */
> >> >> > +/* { dg-options "-O2 -fdump-tree-optimized" } */
> >> >> > +
> >> >> > +
> >> >> > +/* Same form as PR.  */
> >> >> > +__attribute__((noipa)) unsigned int foo(int x) {
> >> >> > +    return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* Signed function.  */
> >> >> > +__attribute__((noipa)) int bar(int x) {
> >> >> > +    return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* Commutative property.  */
> >> >> > +__attribute__((noipa)) unsigned int baz(int x) {
> >> >> > +    return (x <= 0 ? -x : 0) + (x >= 0 ? x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* Flipped order for max expressions.  */
> >> >> > +__attribute__((noipa)) unsigned int quux(int x) {
> >> >> > +    return (0 <= x ? x : 0) + (0 >= x ? -x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* Not zero so should not optimize.  */
> >> >> > +__attribute__((noipa)) unsigned int waldo(int x) {
> >> >> > +    return (x >= 4 ? x : 4) + (x <= 4 ? -x : 4);
> >> >> > +}
> >> >> > +
> >> >> > +/* Not zero so should not optimize.  */
> >> >> > +__attribute__((noipa)) unsigned int fred(int x) {
> >> >> > +    return (x >= -4 ? x : -4) + (x <= -4 ? -x : -4);
> >> >> > +}
> >> >> > +
> >> >> > +/* Incorrect pattern.  */
> >> >> > +__attribute__((noipa)) unsigned int goo(int x) {
> >> >> > +    return (x <= 0 ? x : 0) + (x >= 0 ? -x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* Incorrect pattern.  */
> >> >> > +__attribute__((noipa)) int qux(int x) {
> >> >> > +    return (x >= 0 ? x : 0) + (x >= 0 ? x : 0);
> >> >> > +}
> >> >> > +
> >> >> > +/* { dg-final {scan-tree-dump-times " ABS_EXPR " 4 "optimized" }
> } */
> >> >> >
> >> >> > base-commit: 6af530f914801f5e561057da55c41480f28751f7
> >> >> > --
> >> >> > 2.31.1
> >> >> >
> >> >>
> >>
>
>

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From 894b10a6a9802eeee90524692dd6a00bf2c4261c Mon Sep 17 00:00:00 2001
From: Sam Feifer <sfeifer@redhat.com>
Date: Fri, 15 Jul 2022 13:39:23 -0400
Subject: [PATCH] match.pd: Add new abs pattern [PR94290]

This patch is intended to fix a missed optimization in match.pd. It optimizes (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) to just abs(x). Additionally, the pattern (x <= 0 ? -x : 0) now gets optimized to max(-x, 0), which helps with the other simplification rule.

Tests are also included to be added to the testsuite.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

	PR tree-optimization/94290

gcc/ChangeLog:

	* match.pd (x >= 0 ? x : 0) + (x <= 0 ? -x : 0): New simplification.
	* match.pd (x <= 0 ? -x : 0): New simplification.

gcc/testsuite/ChangeLog:

	* g++.dg/pr94290-1.C: New test.
	* g++.dg/pr94290.C: New test.
	* gcc.dg/pr94290-2.c: New test.
---
 gcc/match.pd                     | 10 +++++
 gcc/testsuite/g++.dg/pr94290-1.C | 17 +++++++++
 gcc/testsuite/g++.dg/pr94290.C   | 63 ++++++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/pr94290-2.c | 15 ++++++++
 4 files changed, 105 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/pr94290-1.C
 create mode 100644 gcc/testsuite/g++.dg/pr94290.C
 create mode 100644 gcc/testsuite/gcc.dg/pr94290-2.c

diff --git a/gcc/match.pd b/gcc/match.pd
index 45aefd96688..ed6609295db 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7848,3 +7848,13 @@ and,
       (if (TYPE_UNSIGNED (TREE_TYPE (@0)))
         (bit_and @0 @1)
       (cond (le @0 @1) @0 (bit_and @0 @1))))))
+
+/* (x >= 0 ? x : 0) + (x <= 0 ? -x : 0) -> abs x.  */
+(simplify
+  (plus:c (max @0 integer_zerop) (max (negate @0) integer_zerop))
+  (abs @0))
+
+/* (x <= 0 ? -x : 0) -> max(-x, 0).  */
+(simplify
+ (cond (le @0 integer_zerop@1) (negate @0) integer_zerop@1)
+ (max (negate @0) @1))
diff --git a/gcc/testsuite/g++.dg/pr94290-1.C b/gcc/testsuite/g++.dg/pr94290-1.C
new file mode 100644
index 00000000000..954408c069f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr94290-1.C
@@ -0,0 +1,17 @@
+/* PR tree-optimization/94290 */
+/* { dg-do run } */
+
+#include "pr94290.C"
+
+int main() {
+
+    if (foo(0) != 0
+        || foo(-42) != 42
+        || foo(42) != 42
+        || baz(-10) != 10
+        || baz(-10) != 10) {
+            __builtin_abort();
+        }
+    
+    return 0;
+}
diff --git a/gcc/testsuite/g++.dg/pr94290.C b/gcc/testsuite/g++.dg/pr94290.C
new file mode 100644
index 00000000000..072ff327977
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr94290.C
@@ -0,0 +1,63 @@
+/* PR tree-optimization/94290 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+typedef int __attribute__((vector_size(4*sizeof(int)))) vint;
+
+/* Same form as PR.  */
+__attribute__((noipa)) unsigned int foo(int x) {
+    return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
+}
+
+/* Test for forward propogation.  */
+__attribute__((noipa)) unsigned int corge(int x) {
+    int w = (x >= 0 ? x : 0);
+    int y = -x;
+    int z = (y >= 0 ? y : 0);
+    return w + z;
+}
+
+/* Vector case.  */
+__attribute__((noipa)) vint thud(vint x) {
+    vint t = (x >= 0 ? x : 0) ;
+    vint xx = -x;
+    vint t1 =  (xx >= 0 ? xx : 0);
+    return t + t1;
+}
+
+/* Signed function.  */
+__attribute__((noipa)) int bar(int x) {
+    return (x >= 0 ? x : 0) + (x <= 0 ? -x : 0);
+}
+
+/* Commutative property.  */
+__attribute__((noipa)) unsigned int baz(int x) {
+    return (x <= 0 ? -x : 0) + (x >= 0 ? x : 0);
+}
+
+/* Flipped order for max expressions.  */
+__attribute__((noipa)) unsigned int quux(int x) {
+    return (0 <= x ? x : 0) + (0 >= x ? -x : 0);
+}
+
+/* Not zero so should not optimize.  */
+__attribute__((noipa)) unsigned int waldo(int x) {
+    return (x >= 4 ? x : 4) + (x <= 4 ? -x : 4);
+}
+
+/* Not zero so should not optimize.  */
+__attribute__((noipa)) unsigned int fred(int x) {
+    return (x >= -4 ? x : -4) + (x <= -4 ? -x : -4);
+}
+
+/* Incorrect pattern.  */
+__attribute__((noipa)) unsigned int goo(int x) {
+    return (x <= 0 ? x : 0) + (x >= 0 ? -x : 0);
+}
+
+/* Incorrect pattern.  */
+__attribute__((noipa)) int qux(int x) {
+    return (x >= 0 ? x : 0) + (x >= 0 ? x : 0);
+}
+
+/* { dg-final {scan-tree-dump-times " ABS_EXPR " 6 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/pr94290-2.c b/gcc/testsuite/gcc.dg/pr94290-2.c
new file mode 100644
index 00000000000..ea6e55755f5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94290-2.c
@@ -0,0 +1,15 @@
+/* PR tree-optimization/94290 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* Form from PR.  */
+__attribute__((noipa)) unsigned int foo(int x) {
+    return x <= 0 ? -x : 0;
+}
+
+/* Changed order.  */
+__attribute__((noipa)) unsigned int bar(int x) {
+    return 0 >= x ? -x : 0;
+}
+
+/* { dg-final {scan-tree-dump-times " MAX_EXPR " 2 "optimized" } } */

base-commit: 6af530f914801f5e561057da55c41480f28751f7
-- 
2.31.1