Re: [PATCH] c++: zero_init_expr_p of dependent expression

[Jason Merrill via Gcc-patches]

On 6/16/20 9:06 AM, Patrick Palka wrote:

On Thu, Apr 23, 2020 at 5:17 PM Jason Merrill <ja...@redhat.com> wrote:

On 4/23/20 4:09 PM, Patrick Palka wrote:

This fixes a ICE coming from mangle.c:write_expression when compiling the
ranges-v3 testsuite; the added testcase is a reduced reproducer of the ICE.

Bootstrapped and regtested on x86_64-pc-linux-gnu, and also tested on the
cmcstl2, fmt and range-v3 libraries.  Does this look OK to commit?

OK.

Is it OK to backport the same patch to the 9 branch in order to resolve PR95678?

OK.

gcc/cp/ChangeLog:> >
       * tree.c (zero_init_expr_p): Use uses_template_parms instead of
       dependent_type_p.

gcc/testsuite/ChangeLog:

       * g++.dg/cpp0x/dependent3.C: New test.
---
   gcc/cp/tree.c                           |  2 +-
   gcc/testsuite/g++.dg/cpp0x/dependent3.C | 28 +++++++++++++++++++++++++
   2 files changed, 29 insertions(+), 1 deletion(-)
   create mode 100644 gcc/testsuite/g++.dg/cpp0x/dependent3.C

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 090c565c093..8840932dba2 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -4486,7 +4486,7 @@ bool
   zero_init_expr_p (tree t)
   {
     tree type = TREE_TYPE (t);
-  if (!type || dependent_type_p (type))
+  if (!type || uses_template_parms (type))
       return false;
     if (zero_init_p (type))
       return initializer_zerop (t);
diff --git a/gcc/testsuite/g++.dg/cpp0x/dependent3.C 
b/gcc/testsuite/g++.dg/cpp0x/dependent3.C
new file mode 100644
index 00000000000..caf7e1cd4a4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/dependent3.C
@@ -0,0 +1,28 @@
+// { dg-do compile { target c++11 } }
+
+template<typename c>
+struct d
+{
+  using e = c;
+};
+
+template<class f>
+struct g
+{
+  using h = typename d<f>::e;
+
+  template<class i, class j>
+  auto operator()(i, j k) -> decltype(h{k});
+};
+
+template<class l>
+void m()
+{
+  int a[1];
+  l{}(a, a);
+}
+
+int main()
+{
+  m<g<int *>>();
+}