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From: Jakub Jelinek <jakub@redhat.com>
To: Jason Merrill <jason@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: [C++ PATCH] Constexpr fold even some TREE_CONSTANT ctors (PR c++/87934)
Date: Tue, 18 Dec 2018 20:45:00 -0000	[thread overview]
Message-ID: <20181218204517.GS23305@tucnak> (raw)

Hi!

The following testcase FAILs, because parsing creates a TREE_CONSTANT
CONSTRUCTOR that contains CONST_DECL elts.  cp_fold_r can handle that,
but constexpr evaluation doesn't touch those CONSTRUCTORs.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2018-12-18  Jakub Jelinek  <jakub@redhat.com>

	PR c++/87934
	* constexpr.c (cxx_eval_constant_expression) <case CONSTRUCTOR>: Do
	re-process TREE_CONSTANT CONSTRUCTORs if they aren't reduced constant
	expressions.

	* g++.dg/cpp0x/constexpr-87934.C: New test.

--- gcc/cp/constexpr.c.jj	2018-12-12 23:43:57.263128844 +0100
+++ gcc/cp/constexpr.c	2018-12-18 14:43:33.460553853 +0100
@@ -4681,7 +4681,7 @@ cxx_eval_constant_expression (const cons
       break;
 
     case CONSTRUCTOR:
-      if (TREE_CONSTANT (t))
+      if (TREE_CONSTANT (t) && reduced_constant_expression_p (t))
 	{
 	  /* Don't re-process a constant CONSTRUCTOR, but do fold it to
 	     VECTOR_CST if applicable.  */
--- gcc/testsuite/g++.dg/cpp0x/constexpr-87934.C.jj	2018-12-18 15:05:56.318886878 +0100
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-87934.C	2018-12-18 15:02:10.652524999 +0100
@@ -0,0 +1,9 @@
+// PR c++/87934
+// { dg-do compile { target c++11 } }
+
+struct Foo
+{
+  enum { BAR } bar = BAR;
+};
+
+constexpr Foo foo{};

	Jakub

             reply	other threads:[~2018-12-18 20:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-18 20:45 Jakub Jelinek [this message]
2018-12-18 22:40 ` Jason Merrill
2018-12-18 23:19   ` Jakub Jelinek
2018-12-19  3:28     ` Jason Merrill
2018-12-19 23:14       ` Jakub Jelinek
2018-12-20 16:01         ` Jason Merrill

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