re PR c++/82541 (Wduplicated-branches triggers in template context)

	PR c++/82541
	* call.c (build_conditional_expr_1): Check complain before warning.
	* pt.c (tsubst_copy_and_build) <case COND_EXPR>: Suppress
	-Wduplicated-branches.

	* g++.dg/warn/Wduplicated-branches4.C: New test.

From-SVN: r256441

gcc/cp/ChangeLog

+2018-01-10  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/82541
+	* call.c (build_conditional_expr_1): Check complain before warning.
+	* pt.c (tsubst_copy_and_build) <case COND_EXPR>: Suppress
+	-Wduplicated-branches.
+
 2018-01-10  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/81327

gcc/cp/call.c

@@ -5345,6 +5345,7 @@ build_conditional_expr_1 (location_t loc, tree arg1, tree arg2, tree arg3,
   /* If the ARG2 and ARG3 are the same and don't have side-effects,
      warn here, because the COND_EXPR will be turned into ARG2.  */
   if (warn_duplicated_branches
+      && (complain & tf_warning)
       && (arg2 == arg3 || operand_equal_p (arg2, arg3, 0)))
     warning_at (EXPR_LOCATION (result), OPT_Wduplicated_branches,
 		"this condition has identical branches");

gcc/cp/pt.c

@@ -17846,6 +17846,7 @@ tsubst_copy_and_build (tree t,
 	    exp2 = RECUR (TREE_OPERAND (t, 2));
 	  }
 
+	warning_sentinel s(warn_duplicated_branches);
 	RETURN (build_x_conditional_expr (EXPR_LOCATION (t),
 					 cond, exp1, exp2, complain));
       }

gcc/testsuite/ChangeLog

+2018-01-10  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/82541
+	* g++.dg/warn/Wduplicated-branches4.C: New test.
+
 2018-01-10  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/81327

gcc/testsuite/g++.dg/warn/Wduplicated-branches4.C

+// PR c++/82541
+// { dg-do compile }
+// { dg-options "-Wduplicated-branches" }
+
+template<int N>
+struct AR
+{
+    char a1[N > 0 ? N : 1]; // { dg-bogus "this condition has identical branches" }
+    char a2[N > 0 ? 1 : 1]; // { dg-warning "this condition has identical branches" }
+};
+
+int
+main ()
+{
+    AR<1> w;
+}