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 set bits into account in popcount [PR107053]
Date: Wed, 12 Jul 2023 23:15:27 +0200 [thread overview]
Message-ID: <20230712211528.65888-1-aldyh@redhat.com> (raw)
This patch teaches popcount about known set bits which are now
available in the irange.
PR tree-optimization/107053
gcc/ChangeLog:
* gimple-range-op.cc (cfn_popcount): Use known set bits.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr107053.c: New test.
---
gcc/gimple-range-op.cc | 11 +++++++----
gcc/testsuite/gcc.dg/tree-ssa/pr107053.c | 13 +++++++++++++
2 files changed, 20 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr107053.c
diff --git a/gcc/gimple-range-op.cc b/gcc/gimple-range-op.cc
index 72c7b866f90..67b3c3d015e 100644
--- a/gcc/gimple-range-op.cc
+++ b/gcc/gimple-range-op.cc
@@ -880,17 +880,20 @@ public:
if (lh.undefined_p ())
return false;
unsigned prec = TYPE_PRECISION (type);
- wide_int nz = lh.get_nonzero_bits ();
- wide_int pop = wi::shwi (wi::popcount (nz), prec);
+ irange_bitmask bm = lh.get_bitmask ();
+ wide_int nz = bm.get_nonzero_bits ();
+ wide_int high = wi::shwi (wi::popcount (nz), prec);
// Calculating the popcount of a singleton is trivial.
if (lh.singleton_p ())
{
- r.set (type, pop, pop);
+ r.set (type, high, high);
return true;
}
if (cfn_ffs::fold_range (r, type, lh, rh, rel))
{
- int_range<2> tmp (type, wi::zero (prec), pop);
+ wide_int known_ones = ~bm.mask () & bm.value ();
+ wide_int low = wi::shwi (wi::popcount (known_ones), prec);
+ int_range<2> tmp (type, low, high);
r.intersect (tmp);
return true;
}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr107053.c b/gcc/testsuite/gcc.dg/tree-ssa/pr107053.c
new file mode 100644
index 00000000000..8195d0f57b4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr107053.c
@@ -0,0 +1,13 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-evrp" }
+
+void link_failure();
+void f(int a)
+{
+ a |= 0x300;
+ int b = __builtin_popcount(a);
+ if (b < 2)
+ link_failure();
+}
+
+// { dg-final { scan-tree-dump-not "link_failure" "evrp" } }
--
2.40.1
next 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 Aldy Hernandez [this message]
2023-07-12 21:15 ` [COMMITTED] [range-op] Take known mask into account for bitwise ands [PR107043] Aldy Hernandez
2023-07-12 21:50 ` [COMMITTED] [range-op] Take known set bits into account in popcount [PR107053] Jeff Law
2023-07-14 11:21 ` Aldy Hernandez
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