From 87713c6a507659921278d32b66f2e344b7c4d124 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Mon, 18 Jul 2016 20:43:19 +0200
Subject: [PATCH] re PR c++/71828 (ICE on valid C++11 code with constexpr
 __Complex int variable declaration: in operand_equal_p, at fold-const.c:2790)

	PR c++/71828
	* constexpr.c (cxx_eval_constant_expression) <case REALPART_EXPR>:
	For lval don't use cxx_eval_unary_expression and instead recurse
	and if needed rebuild the reference.

	* g++.dg/cpp0x/constexpr-71828.C: New test.

From-SVN: r238442
---
 gcc/cp/ChangeLog                             |  5 +++++
 gcc/cp/constexpr.c                           | 13 +++++++++++++
 gcc/testsuite/ChangeLog                      |  3 +++
 gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C |  5 +++++
 4 files changed, 26 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 899b2ae..87d666e 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 2016-07-18  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/71828
+	* constexpr.c (cxx_eval_constant_expression) <case REALPART_EXPR>:
+	For lval don't use cxx_eval_unary_expression and instead recurse
+	and if needed rebuild the reference.
+
 	PR c++/71826
 	* pt.c (tsubst_baselink): Only set BASELINK_OPTYPE for BASELINK_P.
 
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index cb8ece0..91d14a5 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -3800,6 +3800,19 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 
     case REALPART_EXPR:
     case IMAGPART_EXPR:
+      if (lval)
+	{
+	  r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval,
+					    non_constant_p, overflow_p);
+	  if (r == error_mark_node)
+	    ;
+	  else if (r == TREE_OPERAND (t, 0))
+	    r = t;
+	  else
+	    r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r);
+	  break;
+	}
+      /* FALLTHRU */
     case CONJ_EXPR:
     case FIX_TRUNC_EXPR:
     case FLOAT_EXPR:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 060fceb..ff3e335 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2016-07-18  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/71828
+	* g++.dg/cpp0x/constexpr-71828.C: New test.
+
 	PR c++/71826
 	* g++.dg/template/pr71826.C: New test.
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C
new file mode 100644
index 0000000..b74cde9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C
@@ -0,0 +1,5 @@
+// PR c++/71828
+// { dg-do compile { target c++11 } }
+
+constexpr _Complex int a { 1, 2 };
+static_assert (& __imag a != &__real a, "");
-- 
2.7.4