[PATCH] MATCH: Add `(x | c) & ~(y | c)` and `x & ~(y | x)` patterns [PR98710]

Andrew Pinski apinski@marvell.com
Mon Sep 4 01:25:36 GMT 2023


Adding some more simple bit_and/bit_ior patterns.
How often these show up, I have no idea.

This was tested on top of
https://gcc.gnu.org/pipermail/gcc-patches/2023-September/629174.html .

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	PR tree-optimization/98710
	* match.pd (`(x | c) & ~(y | c)`, `(x & c) | ~(y & c)`): New pattern.
	(`x & ~(y | x)`, `x | ~(y & x)`): New patterns.

gcc/testsuite/ChangeLog:

	PR tree-optimization/98710
	* gcc.dg/tree-ssa/andor-7.c: New test.
	* gcc.dg/tree-ssa/andor-8.c: New test.
---
 gcc/match.pd                            | 14 +++++++++++++-
 gcc/testsuite/gcc.dg/tree-ssa/andor-7.c | 16 ++++++++++++++++
 gcc/testsuite/gcc.dg/tree-ssa/andor-8.c | 19 +++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/andor-7.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/andor-8.c

diff --git a/gcc/match.pd b/gcc/match.pd
index 3495f9451d1..a3f507a1e2e 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1995,7 +1995,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   /* (x & y) | (x | z) -> (x | z) */
  (simplify
   (bitop:c (rbitop:c @0 @1) (bitop:c@3 @0 @2))
-  @3))
+  @3)
+ /* (x | c) & ~(y | c) -> x & ~(y | c) */
+ /* (x & c) | ~(y & c) -> x | ~(y & c) */
+ (simplify
+  (bitop:c (rbitop:c @0 @1) (bit_not@3 (rbitop:c @1 @2)))
+  (bitop @0 @3))
+ /* x & ~(y | x) -> 0 */
+ /* x | ~(y & x) -> -1 */
+ (simplify
+  (bitop:c @0 (bit_not (rbitop:c @0 @1)))
+  (if (bitop == BIT_AND_EXPR)
+   { build_zero_cst (type); }
+   { build_minus_one_cst (type); })))
 
 /* ((x | y) & z) | x -> (z & y) | x
    ((x ^ y) & z) | x -> (z & y) | x  */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/andor-7.c b/gcc/testsuite/gcc.dg/tree-ssa/andor-7.c
new file mode 100644
index 00000000000..63b70fa7888
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/andor-7.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+/* PR tree-optimization/98710 */
+
+signed foo(signed x, signed y, signed z)
+{
+    return (x | z) & ~(y | z); // x & ~(y | z);
+}
+// Note . here is `(` or `)`
+/* { dg-final { scan-tree-dump "return x \& ~.y \\| z.;|return ~.y \\| z. \& x;" "original" } } */
+
+signed foo_or(signed a, signed b, signed c)
+{
+    return (a & c) | ~(b & c); // a | ~(b & c);
+}
+/* { dg-final { scan-tree-dump "return a \\| ~.b \& c.;|return ~.b \& c. \\| a;" "original" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/andor-8.c b/gcc/testsuite/gcc.dg/tree-ssa/andor-8.c
new file mode 100644
index 00000000000..0c2eb4c1a00
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/andor-8.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+/* PR tree-optimization/98710 */
+
+signed foo2(signed a, signed b, signed c)
+{
+    return (a & ~(b | a)) & c; // 0
+}
+/* { dg-final { scan-tree-dump "return 0;" "original" } } */
+signed foo2_or(signed x, signed y, signed z)
+{
+    return (x | ~(y & x)) & z; // -1 & z -> z
+}
+
+/* { dg-final { scan-tree-dump "return z;" "original" } } */
+/* All | and & should have been removed. */
+/* { dg-final { scan-tree-dump-not "~" "original" } } */
+/* { dg-final { scan-tree-dump-not " \& " "original" } } */
+/* { dg-final { scan-tree-dump-not " \\| " "original" } } */
-- 
2.31.1



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