> See PR97840.
Thanks,
this is a false positive where we fail to discover that pointed-to type
is empty on non-x86_64 targets. This is triggered by better alias
analysis caused by non-escape discovery.
While this is not a full fix (I hope someone with more experience on
C++ types and warnings will set up) I think it may be useful to avoid
warning on unused parameter.
Bootstrapped/regtested x86_64-linux, OK?
PR middle-end/97840
* tree-ssa-uninit.c (maybe_warn_pass_by_reference): Update prototype;
silence warning on EAF_UNUSED parameters.
(warn_uninitialized_vars): Update.
diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c
index f23514395e0..1e074793b02 100644
--- a/gcc/tree-ssa-uninit.c
+++ b/gcc/tree-ssa-uninit.c
@@ -443,7 +443,7 @@ maybe_warn_operand (ao_ref &ref, gimple *stmt, tree lhs,
tree rhs,
access implying read access to those objects. */
static void
-maybe_warn_pass_by_reference (gimple *stmt, wlimits &wlims)
+maybe_warn_pass_by_reference (gcall *stmt, wlimits &wlims)
{
if (!wlims.wmaybe_uninit)
return;
@@ -501,6 +501,10 @@ maybe_warn_pass_by_reference (gimple *stmt, wlimits &wlims)
&& !TYPE_READONLY (TREE_TYPE (argtype)))
continue;
+ /* Ignore args we are not going to read from. */
+ if (gimple_call_arg_flags (stmt, argno - 1) & EAF_UNUSED)
+ continue;
+
if (save_always_executed && access->mode == access_read_only)
/* Attribute read_only arguments imply read access. */
wlims.always_executed = true;
@@ -639,8 +643,8 @@ warn_uninitialized_vars (bool wmaybe_uninit)
if (gimple_vdef (stmt))
wlims.vdef_cnt++;
- if (is_gimple_call (stmt))
- maybe_warn_pass_by_reference (stmt, wlims);
+ if (gcall *call = dyn_cast <gcall *> (stmt))
+ maybe_warn_pass_by_reference (call, wlims);
else if (gimple_assign_load_p (stmt)
&& gimple_has_location (stmt))
{
