On Wed, Feb 24, 2021 at 01:32:02PM +0100, Richard Biener wrote:
> Small comment about the patch below, which otherwise is OK:
>
> I think that !INTEGRAL_TYPE_P (TREE_TYPE (innerop)) is a sufficient
> condition here.
Unfortunately as shown during the bootstrap, that patch contained a fatal
thinko,
> > + default:
> > + break;
for default: we need return;
Here is a version of the patch that passed bootstrap/regtest on x86_64-linux
and i686-linux, ok for trunk?
2021-02-24 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/80635
* tree-vrp.c (vrp_simplify_cond_using_ranges): Also handle
VIEW_CONVERT_EXPR if modes are the same, innerop is integral and
has mode precision.
* g++.dg/warn/pr80635-1.C: New test.
* g++.dg/warn/pr80635-2.C: New test.
--- gcc/tree-vrp.c.jj 2021-02-24 12:56:58.573939572 +0100
+++ gcc/tree-vrp.c 2021-02-24 13:05:22.675326780 +0100
@@ -4390,11 +4390,22 @@ vrp_simplify_cond_using_ranges (vr_value
gimple *def_stmt = SSA_NAME_DEF_STMT (op0);
tree innerop;
- if (!is_gimple_assign (def_stmt)
- || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
+ if (!is_gimple_assign (def_stmt))
return;
- innerop = gimple_assign_rhs1 (def_stmt);
+ switch (gimple_assign_rhs_code (def_stmt))
+ {
+ CASE_CONVERT:
+ innerop = gimple_assign_rhs1 (def_stmt);
+ break;
+ case VIEW_CONVERT_EXPR:
+ innerop = TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0);
+ if (!INTEGRAL_TYPE_P (TREE_TYPE (innerop)))
+ return;
+ break;
+ default:
+ return;
+ }
if (TREE_CODE (innerop) == SSA_NAME
&& !POINTER_TYPE_P (TREE_TYPE (innerop))
--- gcc/testsuite/g++.dg/warn/pr80635-1.C.jj 2021-02-24 12:24:15.176834532
+0100
+++ gcc/testsuite/g++.dg/warn/pr80635-1.C 2021-02-24 12:24:15.176834532
+0100
@@ -0,0 +1,46 @@
+// PR tree-optimization/80635
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -Wmaybe-uninitialized" }
+
+using size_t = decltype (sizeof (1));
+inline void *operator new (size_t, void *p) { return p; }
+template<typename T>
+struct optional
+{
+ optional () : m_dummy (), live (false) {}
+ void emplace () { new (&m_item) T (); live = true; }
+ ~optional () { if (live) m_item.~T (); }
+
+ union
+ {
+ struct {} m_dummy;
+ T m_item;
+ };
+ bool live;
+};
+
+extern int get ();
+extern void set (int);
+
+struct A
+{
+ A () : m (get ()) {}
+ ~A () { set (m); } // { dg-bogus "may be used uninitialized in this
function" }
+
+ int m;
+};
+
+struct B
+{
+ B ();
+ ~B ();
+};
+
+void func ()
+{
+ optional<A> maybe_a;
+ optional<B> maybe_b;
+
+ maybe_a.emplace ();
+ maybe_b.emplace ();
+}
--- gcc/testsuite/g++.dg/warn/pr80635-2.C.jj 2021-02-24 12:24:15.176834532
+0100
+++ gcc/testsuite/g++.dg/warn/pr80635-2.C 2021-02-24 12:24:15.176834532
+0100
@@ -0,0 +1,31 @@
+// PR tree-optimization/80635
+// { dg-do compile { target c++17 } }
+// { dg-options "-O2 -Wmaybe-uninitialized" }
+
+#include <optional>
+
+extern int get ();
+extern void set (int);
+
+struct A
+{
+ A () : m (get ()) {}
+ ~A () { set (m); } // { dg-bogus "may be used uninitialized in this
function" }
+
+ int m;
+};
+
+struct B
+{
+ B ();
+ ~B ();
+};
+
+void func ()
+{
+ std::optional<A> maybe_a;
+ std::optional<B> maybe_b;
+
+ maybe_a.emplace ();
+ maybe_b.emplace ();
+}
Jakub
