https://gcc.gnu.org/g:dae2b6246c00f4389b617ffaa30459bd22d9fe13
commit r15-7114-gdae2b6246c00f4389b617ffaa30459bd22d9fe13
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Wed Jan 15 20:17:09 2025 -0800
match: Improve the `x ==/!= ~x` pattern [PR118483]
This improves this pattern by 2 ways:
* Allow for an optional convert, similar to how the few other
`a OP ~a` patterns also allow for an optional convert.
* Use bitwise_inverted_equal_p/maybe_bit_not instead of directly
matching bit_not. Just like the other patterns do too.
Note pr118483-2.c used to optimized for aarch64-linux-gnu with GCC 4.9.4
on the RTL level even though the gimple level was missing it.
PR tree-optimization/118483
gcc/ChangeLog:
* match.pd (`x ==/!= ~x`): Allow for an optional convert
and use itwise_inverted_equal_p/maybe_bit_not instead of
directly matching bit_not.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr118483-1.c: New test.
* gcc.dg/tree-ssa/pr118483-2.c: New test.
* gcc.dg/tree-ssa/pr118483-3.c: New test.
* gcc.dg/tree-ssa/pr118483-4.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Diff:
---
gcc/match.pd | 7 +++++--
gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c | 18 ++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c | 18 ++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c | 14 ++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c | 11 +++++++++++
5 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/gcc/match.pd b/gcc/match.pd
index f4359d3a005a..1cdc7e94f1fe 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6959,8 +6959,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* x != ~x -> true */
(for cmp (eq ne)
(simplify
- (cmp:c @0 (bit_not @0))
- { constant_boolean_node (cmp == NE_EXPR, type); }))
+ (cmp:c (convert? @0) (convert? (maybe_bit_not @1)))
+ (with { bool wascmp; }
+ (if (types_match (TREE_TYPE (@0), TREE_TYPE (@1))
+ && bitwise_inverted_equal_p (@0, @1, wascmp))
+ { constant_boolean_node (cmp == NE_EXPR, type); }))))
/* Fold ~X op ~Y as Y op X. */
(for cmp (simple_comparison)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
new file mode 100644
index 000000000000..e31876c940a2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* PR tree-optimization/118483 */
+/* { dg-final { scan-tree-dump-not "abort " "optimized" } } */
+
+
+/* The value of `l == e` is always false as it is
+ `(b == 0) == (b != 0)`. */
+
+int d;
+int f(int b)
+{
+ int e = b == 0;
+ d = e;
+ int l = b != 0;
+ if (l == e)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
new file mode 100644
index 000000000000..84867719867d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-2.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* PR tree-optimization/118483 */
+/* { dg-final { scan-tree-dump-not "abort " "optimized" } } */
+
+
+/* The value of `l == e` is always false as it is
+ `(b == 0) == (b != 0)`. */
+
+int d;
+int f(int b)
+{
+ int e = b == 0;
+ d = e;
+ int l = !e;
+ if (l == e)
+ __builtin_abort ();
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
new file mode 100644
index 000000000000..65efaf5c30fd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-3.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* PR tree-optimization/118483 */
+/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
+
+/* This should optimize down to just `return 0;` */
+/* as `(short)a == ~(short)a` is always false. */
+int f(int a)
+{
+ short b = a;
+ int e = ~a;
+ short c = e;
+ return b == c;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
new file mode 100644
index 000000000000..c6e389c46743
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr118483-4.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* PR tree-optimization/118483 */
+/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
+
+/* This should optimize down to just `return 0;` */
+/* as `a == 0` and `a != 0` are opposites. */
+int f(int a)
+{
+ return (a == 0) == (a != 0);
+}
