> _Complex int are strange beasts, I'd simply avoid the transform for them.
>
>
I added to the match.pd rule to not simplify if the operands are complex.
There is now a test case for complex types to make sure they do not
simplify. I had to move the "dg-do run" test to g++.dg to accommodate the
complex type function that is included (even though there isn't a runtime
test for complex types).
Can you please move the pattern next to the existing div/mod patterns,
> like after the related
>
>
done :)
/* Simplify (A / B) * B + (A % B) -> A. */
> (for div (trunc_div ceil_div floor_div round_div)
> mod (trunc_mod ceil_mod floor_mod round_mod)
> (simplify
> (plus:c (mult:c (div @0 @1) @1) (mod @0 @1))
> @0))
>
> pattern?
>
> +/* x / y * y == x -> x % y == 0. */
> +(simplify
> + (eq (mult (trunc_div @0 @1) @1) @0)
> + (eq (trunc_mod @0 @1) { build_zero_cst TREE_TYPE(@0); }))
>
> there are parens missing around the TREE_TYPE (@0), how did you test
> the patch? You probably want :s on the trunc_div and as Andrew said
> :c on the eq and the mult.
>
I made those changes to the rule. The rule worked without the parentheses,
which is probably why I didn't notice they were missing. Attached is an
updated patch file.
Thanks
-Sam
> Richard.
>
> > Thanks
> > -Sam
> >
> >
> > > For vector try (which works for both the C and C++ front-end):
> > > #define vector __attribute__((vector_size(4*sizeof(int)) ))
> > > vector int f(vector int x, vector int y)
> > > {
> > > return x == x / y * y;
> > > }
> > >
> > > That is for the vector case, == still returns a vector type.
> > >
> > > Thanks,
> > > Andrew Pinski
> > >
> > > >
> > > > Thanks
> > > > -Sam
> > > >
> > > >> Thanks,
> > > >> Andrew Pinski
> > > >>
> > > >> > diff --git a/gcc/testsuite/gcc.dg/pr104992-1.c
> > > b/gcc/testsuite/gcc.dg/pr104992-1.c
> > > >> > new file mode 100644
> > > >> > index 00000000000..a80e5e180ce
> > > >> > --- /dev/null
> > > >> > +++ b/gcc/testsuite/gcc.dg/pr104992-1.c
> > > >> > @@ -0,0 +1,30 @@
> > > >> > +/* PR tree-optimization/104992 */
> > > >> > +/* { dg-do run } */
> > > >> > +/* { dg-options "-O2"} */
> > > >> > +
> > > >> > +#include "pr104992.c"
> > > >> > +
> > > >> > +int main () {
> > > >> > +
> > > >> > + /* Should be true. */
> > > >> > + if (!foo(6, 3)
> > > >> > + || !bar(12, 2)
> > > >> > + || !baz(34, 17)
> > > >> > + || !qux(50, 10)
> > > >> > + || !fred(16, 8)
> > > >> > + || !baz(-9, 3)
> > > >> > + || !baz(9, -3)
> > > >> > + || !baz(-9, -3)
> > > >> > + ) {
> > > >> > + __builtin_abort();
> > > >> > + }
> > > >> > +
> > > >> > + /* Should be false. */
> > > >> > + if (foo(5, 30)
> > > >> > + || bar(72, 27)
> > > >> > + || baz(42, 15)) {
> > > >> > + __builtin_abort();
> > > >> > + }
> > > >> > +
> > > >> > + return 0;
> > > >> > +}
> > > >> > diff --git a/gcc/testsuite/gcc.dg/pr104992.c
> > > b/gcc/testsuite/gcc.dg/pr104992.c
> > > >> > new file mode 100644
> > > >> > index 00000000000..b4b0ca53118
> > > >> > --- /dev/null
> > > >> > +++ b/gcc/testsuite/gcc.dg/pr104992.c
> > > >> > @@ -0,0 +1,35 @@
> > > >> > +/* PR tree-optimization/104992 */
> > > >> > +/* { dg-do compile } */
> > > >> > +/* { dg-options "-O2 -fdump-tree-optimized" } */
> > > >> > +
> > > >> > +/* Form from PR. */
> > > >> > +__attribute__((noipa)) unsigned foo(unsigned x, unsigned y)
> > > >> > +{
> > > >> > + return x / y * y == x;
> > > >> > +}
> > > >> > +
> > > >> > +__attribute__((noipa)) unsigned bar(unsigned x, unsigned y) {
> > > >> > + return x == x / y * y;
> > > >> > +}
> > > >> > +
> > > >> > +/* Signed test case. */
> > > >> > +__attribute__((noipa)) unsigned baz (int x, int y) {
> > > >> > + return x / y * y == x;
> > > >> > +}
> > > >> > +
> > > >> > +/* Changed order. */
> > > >> > +__attribute__((noipa)) unsigned qux (unsigned x, unsigned y) {
> > > >> > + return y * (x / y) == x;
> > > >> > +}
> > > >> > +
> > > >> > +/* Wrong order. */
> > > >> > +__attribute__((noipa)) unsigned fred (unsigned x, unsigned y) {
> > > >> > + return y * x / y == x;
> > > >> > +}
> > > >> > +
> > > >> > +/* Wrong pattern. */
> > > >> > +__attribute__((noipa)) unsigned waldo (unsigned x, unsigned y,
> > > unsigned z) {
> > > >> > + return x / y * z == x;
> > > >> > +}
> > > >> > +
> > > >> > +/* { dg-final {scan-tree-dump-times " % " 4 "optimized" } } */
> > > >> >
> > > >> > base-commit: 633e9920589ddfaf2d6da1c24ce99b18a2638db4
> > > >> > --
> > > >> > 2.31.1
> > > >> >
> > > >>
> > >
> > >
>
>
From bdcfd7b85e95ec9a649c8083c4fbc1bfb88cea88 Mon Sep 17 00:00:00 2001
From: Sam Feifer <sfei...@redhat.com>
Date: Wed, 27 Jul 2022 15:37:39 -0400
Subject: [PATCH] match.pd: Add new division pattern [PR104992]
This patch fixes a missed optimization in match.pd. It takes the pattern, x / y * y == x, and optimizes it to x % y == 0. This produces fewer instructions. This simplification does not happen for complex types.
There are also tests for the optimizations to be added to the test suite.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR tree-optimization/104992
gcc/ChangeLog:
* match.pd x / y * y == x: New simplification.
gcc/testsuite/ChangeLog:
* g++.dg/pr104992-1.C: New test.
* gcc.dg/pr104992.c: New test.
---
gcc/match.pd | 7 ++++
gcc/testsuite/g++.dg/pr104992-1.C | 30 ++++++++++++++++
gcc/testsuite/gcc.dg/pr104992.c | 57 +++++++++++++++++++++++++++++++
3 files changed, 94 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/pr104992-1.C
create mode 100644 gcc/testsuite/gcc.dg/pr104992.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 9736393061a..1442e4cf8dc 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3981,6 +3981,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(plus:c (mult:c (div @0 @1) @1) (mod @0 @1))
@0))
+/* x / y * y == x -> x % y == 0. */
+(simplify
+ (eq:c (mult:c (trunc_div:s @0 @1) @1) @0)
+ (if (TREE_CODE (TREE_TYPE (@0)) != COMPLEX_TYPE
+ && TREE_CODE (TREE_TYPE (@1)) != COMPLEX_TYPE)
+ (eq (trunc_mod @0 @1) { build_zero_cst (TREE_TYPE(@0)); })))
+
/* ((X /[ex] A) +- B) * A --> X +- A * B. */
(for op (plus minus)
(simplify
diff --git a/gcc/testsuite/g++.dg/pr104992-1.C b/gcc/testsuite/g++.dg/pr104992-1.C
new file mode 100644
index 00000000000..f5696b245ac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr104992-1.C
@@ -0,0 +1,30 @@
+/* PR tree-optimization/104992 */
+/* { dg-do run } */
+/* { dg-options "-O2"} */
+
+#include "../gcc.dg/pr104992.c"
+
+int main () {
+
+ /* Should be true. */
+ if (!foo(6, 3)
+ || !bar(12, 2)
+ || !baz(34, 17)
+ || !qux(50, 10)
+ || !fred(16, 8)
+ || !baz(-9, 3)
+ || !baz(9, -3)
+ || !baz(-9, -3)
+ ) {
+ __builtin_abort();
+ }
+
+ /* Should be false. */
+ if (foo(5, 30)
+ || bar(72, 27)
+ || baz(42, 15)) {
+ __builtin_abort();
+ }
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr104992.c b/gcc/testsuite/gcc.dg/pr104992.c
new file mode 100644
index 00000000000..b9d91a13ad8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr104992.c
@@ -0,0 +1,57 @@
+/* PR tree-optimization/104992 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define vector __attribute__((vector_size(4*sizeof(int))))
+
+/* Form from PR. */
+__attribute__((noipa)) unsigned foo(unsigned x, unsigned y)
+{
+ return x / y * y == x;
+}
+
+__attribute__((noipa)) unsigned bar(unsigned x, unsigned y) {
+ return x == x / y * y;
+}
+
+/* Signed test case. */
+__attribute__((noipa)) unsigned baz (int x, int y) {
+ return x / y * y == x;
+}
+
+/* Changed order. */
+__attribute__((noipa)) unsigned qux (unsigned x, unsigned y) {
+ return y * (x / y) == x;
+}
+
+/* Test for forward propogation. */
+__attribute__((noipa)) unsigned corge(unsigned x, unsigned y) {
+ int z = x / y;
+ int q = z * y;
+ return q == x;
+}
+
+/* Test vector case. */
+__attribute__((noipa)) vector int thud(vector int x, vector int y) {
+ return x / y * y == x;
+}
+
+/* Complex type should not simplify because mod is different. */
+__attribute__((noipa)) int goo(_Complex int x, _Complex int y)
+{
+ _Complex int z = x / y;
+ _Complex int q = z * y;
+ return q == x;
+}
+
+/* Wrong order. */
+__attribute__((noipa)) unsigned fred (unsigned x, unsigned y) {
+ return y * x / y == x;
+}
+
+/* Wrong pattern. */
+__attribute__((noipa)) unsigned waldo (unsigned x, unsigned y, unsigned z) {
+ return x / y * z == x;
+}
+
+/* { dg-final {scan-tree-dump-times " % " 9 "optimized" } } */
base-commit: 633e9920589ddfaf2d6da1c24ce99b18a2638db4
--
2.31.1
