[gcc/devel/omp/gcc-9] c++: Fix ICE in tsubst_copy with parenthesized expression [PR93299]

[Tobias Burnus]

https://gcc.gnu.org/g:2b5d109ba3af320f65cb0707e8733eeea3c96262

commit 2b5d109ba3af320f65cb0707e8733eeea3c96262
Author: Marek Polacek <polacek@redhat.com>
Date:   Wed Mar 4 19:04:31 2020 -0500

    c++: Fix ICE in tsubst_copy with parenthesized expression [PR93299]
    
    	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:
---
 gcc/cp/ChangeLog                    |  8 ++++++++
 gcc/cp/pt.c                         |  8 ++++++++
 gcc/testsuite/g++.dg/cpp1y/paren5.C | 12 ++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 26d9a08..a923606 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,6 +1,14 @@
 2020-03-04  Marek Polacek  <polacek@redhat.com>
 
 	Backported from mainline
+	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.
+
+2020-03-04  Marek Polacek  <polacek@redhat.com>
+
+	Backported from mainline
 	2020-02-26  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/93676 - value-init crash in template.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 2de9036..43d9660 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -15834,6 +15834,14 @@ 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/g++.dg/cpp1y/paren5.C b/gcc/testsuite/g++.dg/cpp1y/paren5.C
new file mode 100644
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> { };