c++: Fix ICE in tsubst_copy with parenthesized expression [PR93299]

Since e4511ca2e9ecdb51d41b64452398f8e2df575668 force_paren_expr can create
a VIEW_CONVERT_EXPR so that we have something to set REF_PARENTHESIZED_P
on, while not making the expression dependent.  But tsubst_copy can't cope
with such a VIEW_CONVERT_EXPR, because it's not location_wrapper_p, or
a TEMPLATE_PARM_INDEX wrapped in a VIEW_CONVERT_EXPR.

I think we need to teach tsubst_copy how to handle it.  Setting
EXPR_LOCATION_WRAPPER_P in force_paren_expr would make the ICE go away
too, but tsubst_copy would lose the REF_PARENTHESIZED_P flag.

2020-01-24  Marek Polacek  <polacek@redhat.com>

	PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
	* pt.c (tsubst_copy): Handle a REF_PARENTHESIZED_P VIEW_CONVERT_EXPR.

	* g++.dg/cpp1y/paren5.C: New test.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b1c9e2c632571523459341517077b24d547b8c44..0ed260b5da1f5cd23275e4d71fb08c3673f6a387 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+       * pt.c (tsubst_copy): Handle a REF_PARENTHESIZED_P VIEW_CONVERT_EXPR.
+
 2020-01-24  Jason Merrill  <jason@redhat.com>
 
        PR c++/92852 - ICE with generic lambda and reference var.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4520c9950287a08e4cd9401f4950cfd92721b8c1..95719927249bb81559dacdbe6f9b0652faaa02ca 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16423,6 +16423,14 @@ tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl)
                  return op;
                }
            }
+         /* force_paren_expr can also create a VIEW_CONVERT_EXPR.  */
+         else if (code == VIEW_CONVERT_EXPR && REF_PARENTHESIZED_P (t))
+           {
+             op = tsubst_copy (op, args, complain, in_decl);
+             op = build1 (code, TREE_TYPE (op), op);
+             REF_PARENTHESIZED_P (op) = true;
+             return op;
+           }
          /* We shouldn't see any other uses of these in templates.  */
          gcc_unreachable ();
        }

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7c6b4cdfa6c8021b39c1bbe502fd91a349c5dee2..d1213ccd44f3aa652a5bb5971dc5af12b005a522 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+       * g++.dg/cpp1y/paren5.C: New test.
+
 2020-01-24  Sandra Loosemore  <sandra@codesourcery.com>
 
        * g++.dg/cpp0x/constexpr-odr1.C: Add -fdelete-null-pointer-checks.

diff --git a/gcc/testsuite/g++.dg/cpp1y/paren5.C b/gcc/testsuite/g++.dg/cpp1y/paren5.C
new file mode 100644 (file)
index 0000000..86a5135
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/paren5.C
@@ -0,0 +1,12 @@
+// PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+// { dg-do compile { target c++14 } }
+
+template <typename> struct A {
+  enum { b = 8 };
+};
+
+template <int> struct __attribute__((aligned((A<int>::b)))) D { };
+struct S : D<0> { };
+
+template <int N> struct __attribute__((aligned((A<int>::b) + N))) D2 { };
+struct S2 : D2<0> { };