https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92831
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Even better testcase that has nested COND_EXPRs:
template<typename T> using id = T;
struct S { S () { s++; } ~S () { s--; } S (int) { s++; } static int s; };
int S::s = 0;
void
bar (bool cond, bool cond2)
{
if (S::s != (cond ? cond2 ? 7 : 5 : cond2 ? 8 : 9))
__builtin_abort ();
}
void
foo (bool cond, bool cond2)
{
int i = 1;
// temporary array has same lifetime as a
S&& a = id<S[3]>{1, 2, 3}[i];
// temporary S has same lifetime as b
const S& b = static_cast<const S&>(0);
// exactly one of the four temporaries is lifetime-extended
S&& c = cond ? cond2 ? id<S[3]>{1, 2, 3}[i] : static_cast<S&&>(0)
: cond2 ? id<S[4]>{1, 2, 3, 4}[i] : id<S[5]>{1, 2, 3, 4, 5}[i];
bar (cond, cond2);
}
int
main ()
{
foo (true, true);
foo (true, false);
foo (false, true);
foo (false, false);
}
--- gcc/cp/call.c.jj 2019-12-05 10:03:04.110181312 +0100
+++ gcc/cp/call.c 2019-12-05 20:35:08.386092965 +0100
@@ -12153,12 +12153,19 @@ extend_ref_init_temps_1 (tree decl, tree
= extend_ref_init_temps_1 (decl, TREE_OPERAND (sub, 1), cleanups);
return init;
}
+ if (TREE_CODE (sub) == COND_EXPR)
+ {
+ TREE_OPERAND (sub, 1)
+ = extend_ref_init_temps_1 (decl, TREE_OPERAND (sub, 1), cleanups);
+ TREE_OPERAND (sub, 2)
+ = extend_ref_init_temps_1 (decl, TREE_OPERAND (sub, 2), cleanups);
+ return init;
+ }
if (TREE_CODE (sub) != ADDR_EXPR)
return init;
/* Deal with binding to a subobject. */
for (p = &TREE_OPERAND (sub, 0);
- (TREE_CODE (*p) == COMPONENT_REF
- || TREE_CODE (*p) == ARRAY_REF); )
+ TREE_CODE (*p) == COMPONENT_REF || TREE_CODE (*p) == ARRAY_REF; )
p = &TREE_OPERAND (*p, 0);
if (TREE_CODE (*p) == TARGET_EXPR)
{
isn't sufficient, because if there are any cleanups added by either of the
recursive calls, we need to conditionalize those cleanups on whether the
particular COND_EXPR's first operand evaluated to true or false. I think
cp_save_expr won't do it for the nested cases though, because the SAVE_EXPR
might end up not being initialized. So we need to arrange for a bool temporary
that will be initialized to say false early, before the first COND_EXPR is
encountered, set it to true at the start of corresponding init code and wrap
cleanups with that guard.
Any better ideas?
