re PR c++/79379 (ICE with #pragma GCC ivdep)

	PR c++/79379
	* constexpr.c (cxx_eval_constant_expression): Handle ANNOTATE_EXPR.
	(potential_constant_expression_1): Likewise.

	* g++.dg/cpp1y/constexpr-79379.C: New test.

From-SVN: r245220

gcc/cp/ChangeLog

 2017-02-06  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/79379
+	* constexpr.c (cxx_eval_constant_expression): Handle ANNOTATE_EXPR.
+	(potential_constant_expression_1): Likewise.
+
 	PR c++/79377
 	* tree.c (build_min_non_dep_op_overload): For POST{INC,DEC}REMENT_EXPR
 	allow one fewer than expected arguments if flag_permissive.

gcc/cp/constexpr.c

@@ -4518,6 +4518,14 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
         *non_constant_p = true;
       return t;
 
+    case ANNOTATE_EXPR:
+      gcc_assert (tree_to_uhwi (TREE_OPERAND (t, 1)) == annot_expr_ivdep_kind);
+      r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0),
+					lval,
+					non_constant_p, overflow_p,
+					jump_target);
+      break;
+
     default:
       if (STATEMENT_CODE_P (TREE_CODE (t)))
 	{
@@ -5689,6 +5697,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict,
 	return false;
       }
 
+    case ANNOTATE_EXPR:
+      gcc_assert (tree_to_uhwi (TREE_OPERAND (t, 1)) == annot_expr_ivdep_kind);
+      return RECUR (TREE_OPERAND (t, 0), rval);
+
     default:
       if (objc_is_property_ref (t))
 	return false;

gcc/testsuite/ChangeLog

 2017-02-06  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/79379
+	* g++.dg/cpp1y/constexpr-79379.C: New test.
+
 	PR c++/79377
 	* g++.dg/lookup/pr79377.C: New test.
 

gcc/testsuite/g++.dg/cpp1y/constexpr-79379.C

+// PR c++/79379
+// { dg-do compile { target c++14 } }
+// { dg-options "-O2" }
+
+template <int N>
+constexpr int
+foo (int x)
+{
+  int q[64] = { 0 }, r = 0;
+#pragma GCC ivdep
+  for (int i = 0; i < x; ++i)
+    q[i] += 2;
+  for (int i = 0; i < x; ++i)
+    r += q[i];
+  return r + N;
+}
+
+constexpr int a = foo<0> (17);
+static_assert (a == 34, "");