This adds handling of uninitialized uses of members in constructors
to the uninit warning machinery.
Bootstrap and regtest on x86_64-unknown-linux-gnu in progress together
with a bootstrap fix to the pass_manager.
Richard.
2017-04-21 Richard Biener <rguent...@suse.de>
PR c++/2972
* tree-ssa-uninit.c (warn_uninitialized_vars): Handle some
pointer-based references.
* g++.dg/warn/Wuninitialized-10.C: New testcase.
Index: gcc/tree-ssa-uninit.c
===================================================================
--- gcc/tree-ssa-uninit.c (revision 247049)
+++ gcc/tree-ssa-uninit.c (working copy)
@@ -279,20 +279,22 @@ warn_uninitialized_vars (bool warn_possi
ao_ref ref;
ao_ref_init (&ref, rhs);
- /* Do not warn if it can be initialized outside this function. */
+ /* Do not warn if the base was marked so or this is a
+ hard register var. */
tree base = ao_ref_base (&ref);
- if (!VAR_P (base)
- || DECL_HARD_REGISTER (base)
- || is_global_var (base)
+ if ((VAR_P (base)
+ && DECL_HARD_REGISTER (base))
|| TREE_NO_WARNING (base))
continue;
/* Do not warn if the access is fully outside of the
variable. */
- if (ref.size != -1
+ if (DECL_P (base)
+ && ref.size != -1
&& ref.max_size == ref.size
&& (ref.offset + ref.size <= 0
|| (ref.offset >= 0
+ && DECL_SIZE (base)
&& TREE_CODE (DECL_SIZE (base)) == INTEGER_CST
&& compare_tree_int (DECL_SIZE (base),
ref.offset) <= 0)))
@@ -305,11 +307,12 @@ warn_uninitialized_vars (bool warn_possi
&& oracle_cnt > vdef_cnt * 2)
limit = 32;
check_defs_data data;
+ bool fentry_reached = false;
data.found_may_defs = false;
use = gimple_vuse (stmt);
int res = walk_aliased_vdefs (&ref, use,
check_defs, &data, NULL,
- NULL, limit);
+ &fentry_reached, limit);
if (res == -1)
{
oracle_cnt += limit;
@@ -318,6 +321,16 @@ warn_uninitialized_vars (bool warn_possi
oracle_cnt += res;
if (data.found_may_defs)
continue;
+ /* Do not warn if it can be initialized outside this function.
+ If we did not reach function entry then we found killing
+ clobbers on all paths to entry. */
+ if (fentry_reached
+ /* ??? We'd like to use ref_may_alias_global_p but that
+ excludes global readonly memory and thus we get bougs
+ warnings from p = cond ? "a" : "b" for example. */
+ && (!VAR_P (base)
+ || is_global_var (base)))
+ continue;
/* We didn't find any may-defs so on all paths either
reached function entry or a killing clobber. */
Index: gcc/testsuite/g++.dg/warn/Wuninitialized-10.C
===================================================================
--- gcc/testsuite/g++.dg/warn/Wuninitialized-10.C (nonexistent)
+++ gcc/testsuite/g++.dg/warn/Wuninitialized-10.C (working copy)
@@ -0,0 +1,14 @@
+// { dg-do compile }
+// { dg-options "-Wuninitialized" }
+
+struct A
+{
+ int f,g;
+
+ A()
+ {
+ f = g; // { dg-warning "g. is used uninitialized" }
+ }
+};
+
+A a;
