C++ PATCH to add test to cover case RANGE_FOR_STMT

Message ID 20181012012838.GL19003@redhat.com
State New
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Series
  • C++ PATCH to add test to cover case RANGE_FOR_STMT
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Commit Message

Marek Polacek Oct. 12, 2018, 1:28 a.m.
Recently it came up that no test in the testsuite triggers the RANGE_FOR_STMT
case in potential_constant_expression_1.  I came up with this valid test that
tickles that codepath.

I can't use ({ }) instead of a lambda because the constexpr machinery doesn't
handle statement expressions; see default: in cxx_eval_constant_expression.

Tested on x86_64-linux, ok for trunk?

2018-10-11  Marek Polacek  <polacek@redhat.com>

	* g++.dg/cpp1z/constexpr-lambda22.C: New test,

Patch

diff --git gcc/testsuite/g++.dg/cpp1z/constexpr-lambda22.C gcc/testsuite/g++.dg/cpp1z/constexpr-lambda22.C
index e69de29bb2d..8bb473431a5 100644
--- gcc/testsuite/g++.dg/cpp1z/constexpr-lambda22.C
+++ gcc/testsuite/g++.dg/cpp1z/constexpr-lambda22.C
@@ -0,0 +1,20 @@ 
+// { dg-do compile }
+// { dg-options -std=c++17 }
+
+#define SA(X) static_assert((X),#X)
+
+template<typename>
+constexpr int
+foo ()
+{
+  constexpr int a[] = { 1, 2, 3, 4, 5 };
+  int i = 0;
+  auto j = [&] {
+    for (auto x : a)
+      i++;
+    return i;
+  }();
+  return j;
+}
+
+SA (foo<int>() == 5);