[PATCH v3]: testcases for "ICE for unknown parameter to constexpr'd switch-statement, PR113545"

[Hans-Peter Nilsson <hp@axis.com>]

Bah.  Linaro's CI didn't like that there were UNRESOLVEDs
due to this patch.  Running it "as usual" didn't show
anything suspicious.  Sure, there were "# of unresolved
testcases 3" in the summary (see v2), but no error or other
special message from dejagnu.  Perhaps there could be a way
to have dg-ice automatically downgrade a dg-do run that
failed due to the ICE to a dg-do compile (or just not emit
the UNRESOLVED note), but pragmatically, this is a rare
enough case to not bother.  It looks like these were the
only UNRESOLVEDs in that CI run, so I'm just going to make a
mental note and move on.

For more comments, please see v2 of this patch.

v3: Change dg-do run to dg-do compile to avoid an UNRESOLVED.
Tested as with v2.  Ok to commit?

-- >8 --

Test-cases, with constexpr-reinterpret3.C dg-ice:ing the PR c++/113545 bug.

Regarding the request in the comment, a dg-do run when there's an ICE
will cause some CI's to signal an error for the run being "UNRESOLVED"
(compilation failed to produce executable).  Note that dejagnu (1.6.3)
itself doesn't consider this an error.

gcc/testsuite:
	PR c++/113545
	* g++.dg/cpp1y/constexpr-reinterpret3.C,
	g++.dg/cpp1y/constexpr-reinterpret4.C: New tests.
---
 .../g++.dg/cpp1y/constexpr-reinterpret3.C     | 56 +++++++++++++++++++
 .../g++.dg/cpp1y/constexpr-reinterpret4.C     | 54 ++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret4.C

diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
new file mode 100644
index 000000000000..6c396bff72b6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
@@ -0,0 +1,56 @@
+// PR c++/113545
+// { dg-do run { target c++14 } }
+// Please change the above "dg-do compile" to "dg-do run" when the ICE is resolved.
+// { dg-ice "PR112545 - constexpr function with switch called for reinterpret_cast" }
+
+char foo;
+
+// This one caught a call to gcc_unreachable in
+// cp/constexpr.cc:label_matches, when passed a convert_expr from the
+// cast in the call.
+constexpr unsigned char swbar(__UINTPTR_TYPE__ baz)
+{
+  switch (baz)
+    {
+    case 13:
+      return 11;
+    case 14:
+      return 78;
+    case 2048:
+      return 13;
+    default:
+      return 42;
+    }
+}
+
+// For reference, the equivalent* if-statements.
+constexpr unsigned char ifbar(__UINTPTR_TYPE__ baz)
+{
+  if (baz == 13)
+    return 11;
+  else if (baz == 14)
+    return 78;
+  else if (baz == 2048)
+    return 13;
+  else
+    return 42;
+}
+
+__attribute__ ((__noipa__))
+void xyzzy(int x)
+{
+  if (x != 42)
+    __builtin_abort ();
+}
+
+int main()
+{
+  unsigned const char c = swbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
+  xyzzy(c);
+  unsigned const char d = ifbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
+  xyzzy(d);
+  unsigned const char e = swbar((__UINTPTR_TYPE__) &foo);
+  xyzzy(e);
+  unsigned const char f = ifbar((__UINTPTR_TYPE__) &foo);
+  xyzzy(f);
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret4.C
new file mode 100644
index 000000000000..9aaa6e463bc6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret4.C
@@ -0,0 +1,54 @@
+// PR c++/113545
+// { dg-do compile { target c++14 } }
+
+char foo;
+
+// This one caught a call to gcc_unreachable in
+// cp/constexpr.cc:label_matches, when passed a convert_expr from the
+// cast in the call.
+constexpr unsigned char swbar(__UINTPTR_TYPE__ baz)
+{
+  switch (baz)
+    {
+    case 13:
+      return 11;
+    case 14:
+      return 78;
+    case 2048:
+      return 13;
+    default:
+      return 42;
+    }
+}
+
+// For reference, the equivalent* if-statements.
+constexpr unsigned char ifbar(__UINTPTR_TYPE__ baz)
+{
+  if (baz == 13)
+    return 11;
+  else if (baz == 14)
+    return 78;
+  else if (baz == 2048)
+    return 13;
+  else
+    return 42;
+}
+
+__attribute__ ((__noipa__))
+void xyzzy(int x)
+{
+  if (x != 42)
+    __builtin_abort ();
+}
+
+int main()
+{
+  unsigned constexpr char c = swbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo)); // { dg-error "conversion from pointer type" }
+  xyzzy(c);
+  unsigned constexpr char d = ifbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo)); // { dg-error "conversion from pointer type" }
+  xyzzy(d);
+  unsigned constexpr char e = swbar((__UINTPTR_TYPE__) &foo); // { dg-error "conversion from pointer type" }
+  xyzzy(e);
+  unsigned constexpr char f = ifbar((__UINTPTR_TYPE__) &foo); // { dg-error "conversion from pointer type" }
+  xyzzy(f);
+}
-- 
2.30.2