From 010d4a5047166037b316ed22331f3d99742f1f1d Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 11 May 2021 09:53:20 -0400
Subject: [PATCH] c++: ICE casting class to vector [PR100517]

My recent change to reject calling rvalue() with an argument of class type
crashes on this testcase, where we use rvalue() on what we expect to be an
argument of integer or vector type.  Fixed by checking first.

gcc/cp/ChangeLog:

	PR c++/100517
	* typeck.c (build_reinterpret_cast_1): Check intype on
	cast to vector.

gcc/testsuite/ChangeLog:

	PR c++/100517
	* g++.dg/ext/vector41.C: New test.
---
 gcc/cp/typeck.c                     |  2 +-
 gcc/testsuite/g++.dg/ext/vector41.C | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/vector41.C

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 9002dd14faec..703ddd3cc7a6 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -8114,7 +8114,7 @@ build_reinterpret_cast_1 (location_t loc, tree type, tree expr,
 		    "pointer-to-object is conditionally-supported");
       return build_nop_reinterpret (type, expr);
     }
-  else if (gnu_vector_type_p (type))
+  else if (gnu_vector_type_p (type) && scalarish_type_p (intype))
     return convert_to_vector (type, rvalue (expr));
   else if (gnu_vector_type_p (intype)
 	   && INTEGRAL_OR_ENUMERATION_TYPE_P (type))
diff --git a/gcc/testsuite/g++.dg/ext/vector41.C b/gcc/testsuite/g++.dg/ext/vector41.C
new file mode 100644
index 000000000000..bfc3bb6db4bd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vector41.C
@@ -0,0 +1,12 @@
+// PR c++/100517
+// { dg-options "" }
+
+typedef int __v2si __attribute__ ((__vector_size__ (8)));
+
+struct S { };
+
+void
+f (S s)
+{
+  (void) reinterpret_cast<__v2si> (s); // { dg-error "" }
+}
-- 
2.47.2