re PR c++/71828 (ICE on valid C++11 code with constexpr __Complex int variable…

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

 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.
 

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:

gcc/testsuite/ChangeLog

 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.
 

gcc/testsuite/g++.dg/cpp0x/constexpr-71828.C

+// PR c++/71828
+// { dg-do compile { target c++11 } }
+
+constexpr _Complex int a { 1, 2 };
+static_assert (& __imag a != &__real a, "");