diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index c40bc9c15b96..d47c2f74f378 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2019-08-21  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR c++/91505
+	* decl.c (duplicate_decls): Call copy_attributes_to_builtin inside
+	the BUILT_IN_NORMAL block rather than afterward.
+
 2019-08-19  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/91264 - detect modifying const objects in constexpr.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 08b7baa40e00..88aa69ce5deb 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2565,9 +2565,9 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend)
 		    set_builtin_decl_declared_p (fncode, true);
 		  break;
 		}
-	    }
 
-	  copy_attributes_to_builtin (newdecl);
+	      copy_attributes_to_builtin (newdecl);
+	    }
 	}
       if (new_defines_function)
 	/* If defining a function declared with other language
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e8d22d1844df..27c5144436de 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-08-21  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR c++/91505
+	* g++.target/i386/crc32-4.C: New test.
+
 2019-08-21  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91482
diff --git a/gcc/testsuite/g++.target/i386/crc32-4.C b/gcc/testsuite/g++.target/i386/crc32-4.C
new file mode 100644
index 000000000000..542ded640885
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/crc32-4.C
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx2" } */
+
+#include "../../gcc.target/i386/crc32-4.c"