There's a typo in the check against unknown offset when processing
an aggregate copy during VN, leading to wrong lookup.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/123310
* tree-ssa-sccvn.cc (vn_reference_lookup_3): Properly
test against unknown offset.
* gcc.dg/torture/pr123310.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr123310.c | 21 +++++++++++++++++++++
gcc/tree-ssa-sccvn.cc | 2 +-
2 files changed, 22 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr123310.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr123310.c
b/gcc/testsuite/gcc.dg/torture/pr123310.c
new file mode 100644
index 00000000000..1c2dee65c8d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr123310.c
@@ -0,0 +1,21 @@
+/* { dg-do run } */
+
+struct a {
+ short b;
+} c[7], e;
+int d;
+static struct a f[3][2] = {{}, {}, 5, 5};
+void __attribute__((noipa)) g()
+{
+ for (; e.b >= 0; e.b--)
+ {
+ c[e.b + 6] = f[2][1];
+ d = c[6].b;
+ }
+}
+int main()
+{
+ g();
+ if (d != 5)
+ __builtin_abort ();
+}
diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 6fda0ef6044..16343d2a407 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -3694,7 +3694,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void
*data_,
via extra_off. Note this is an attempt to fixup secondary
copies after we hit the !found && j == 0 case above. */
while (j != -1
- && known_ne (lhs_ops[j].off, -1U))
+ && known_ne (lhs_ops[j].off, -1))
{
extra_off += -lhs_ops[j].off;
j--;
--
2.51.0
