backport: re PR c++/72868 (Constexpr expressions mistreat case ranges)

	Backported from mainline
	2016-08-11  Jakub Jelinek  <jakub@redhat.com>

	PR c++/72868
	* constexpr.c (label_matches): Handle case range expressions.

	* g++.dg/cpp1y/constexpr-switch4.C: New test.

From-SVN: r248595

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 8a89f21051b009afdb604659cc7c575e3a78c2b8..167d78e938b1565c9366dfc67ca18eef84fd7736 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2017-05-30  Jakub Jelinek  <jakub@redhat.com>
+
+       Backported from mainline
+       2016-08-11  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c++/72868
+       * constexpr.c (label_matches): Handle case range expressions.
+
 2017-01-12  Nathan Sidwell  <nathan@acm.org>
 
        PR c++/77812

diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index e558e69066ae1cbcc4f5dad77599280747805036..4b34b9c9653f46057afeff4b441398aad8d428bd 100644 (file)
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -3092,6 +3092,12 @@ label_matches (tree *jump_target, tree_stmt_iterator i,
        {
          if (!CASE_LOW (stmt))
            default_label = i;
+         else if (CASE_HIGH (stmt))
+           {
+             if (tree_int_cst_le (CASE_LOW (stmt), *jump_target)
+                 && tree_int_cst_le (*jump_target, CASE_HIGH (stmt)))
+               return true;
+           }
          else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt)))
            return true;
        }

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c416f40649923ebe355b3200b6e0f8df1ffa743e..eccc05634545919ded2202390a389fdc1aaf0ef5 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -3,6 +3,9 @@
        Backported from mainline
        2016-08-11  Jakub Jelinek  <jakub@redhat.com>
 
+       PR c++/72868
+       * g++.dg/cpp1y/constexpr-switch4.C: New test.
+
        PR c/72816
        * gcc.dg/pr72816.c: Remove dg-error.
 

diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-switch4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-switch4.C
new file mode 100644 (file)
index 0000000..383bde9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-switch4.C
@@ -0,0 +1,27 @@
+// PR c++/72868
+// { dg-do compile }
+// { dg-options "-std=gnu++14" }
+
+constexpr int
+foo (int i)
+{
+  switch (i)
+    {
+    case 11 ... 12:
+      return 4;
+    case 0 ... 9:
+      return 3;
+    default:
+      return 7;
+    }
+}
+
+#define SA(X) static_assert((X),#X)
+SA (foo (-1) == 7);
+SA (foo (0) == 3);
+SA (foo (3) == 3);
+SA (foo (9) == 3);
+SA (foo (10) == 7);
+SA (foo (11) == 4);
+SA (foo (12) == 4);
+SA (foo (13) == 7);