From: Aldy Hernandez <aldyh@redhat.com>
To: GCC patches <gcc-patches@gcc.gnu.org>
Cc: Andrew MacLeod <amacleod@redhat.com>, Aldy Hernandez <aldyh@redhat.com>
Subject: [COMMITTED] [range-op] Take known mask into account for bitwise ands [PR107043]
Date: Wed, 12 Jul 2023 23:15:29 +0200 [thread overview]
Message-ID: <20230712211528.65888-2-aldyh@redhat.com> (raw)
In-Reply-To: <20230712211528.65888-1-aldyh@redhat.com>
PR tree-optimization/107043
gcc/ChangeLog:
* range-op.cc (operator_bitwise_and::op1_range): Update bitmask.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr107043.c: New test.
---
gcc/range-op.cc | 8 ++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr107043.c | 22 ++++++++++++++++++++++
2 files changed, 30 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr107043.c
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 56e80c9f3ae..6b5d4f2accd 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -3463,6 +3463,14 @@ operator_bitwise_and::op1_range (irange &r, tree type,
if (r.undefined_p ())
set_nonzero_range_from_mask (r, type, lhs);
+ // For MASK == op1 & MASK, all the bits in MASK must be set in op1.
+ wide_int mask;
+ if (lhs == op2 && lhs.singleton_p (mask))
+ {
+ r.update_bitmask (irange_bitmask (mask, ~mask));
+ return true;
+ }
+
// For 0 = op1 & MASK, op1 is ~MASK.
if (lhs.zero_p () && op2.singleton_p ())
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr107043.c b/gcc/testsuite/gcc.dg/tree-ssa/pr107043.c
new file mode 100644
index 00000000000..af5df225746
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr107043.c
@@ -0,0 +1,22 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-evrp" }
+
+int g0(int n)
+{
+ int n1 = n & 0x8000;
+ if (n1 == 0)
+ return 1;
+ // n1 will be 0x8000 here.
+ return (n1 >> 15) & 0x1;
+}
+
+int g1(int n)
+{
+ int n1 = n & 0x8000;
+ if (n1 == 0)
+ return 1;
+ // n>>15 will be xxxxxx1 here.
+ return (n >> 15) & 0x1;
+}
+
+// { dg-final { scan-tree-dump-times "return 1;" 2 "evrp" } }
--
2.40.1
next prev parent reply other threads:[~2023-07-12 21:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-12 21:15 [COMMITTED] [range-op] Take known set bits into account in popcount [PR107053] Aldy Hernandez
2023-07-12 21:15 ` Aldy Hernandez [this message]
2023-07-12 21:50 ` Jeff Law
2023-07-14 11:21 ` Aldy Hernandez
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