[gcc r14-4747] libcpp: testsuite: Add test for fixed _Pragma bug [PR82335]

[Lewis Hyatt <lhyatt@gcc.gnu.org>]

https://gcc.gnu.org/g:202a214d6859d91af5a95aa989321c5d2173c40a

commit r14-4747-g202a214d6859d91af5a95aa989321c5d2173c40a
Author: Lewis Hyatt <lhyatt@gmail.com>
Date:   Mon Oct 2 14:56:58 2023 -0400

    libcpp: testsuite: Add test for fixed _Pragma bug [PR82335]
    
    This PR was fixed by r12-4797 and r12-5454. Add test coverage from the PR
    that is not represented elsewhere.
    
    gcc/testsuite/ChangeLog:
    
            PR preprocessor/82335
            * c-c++-common/cpp/diagnostic-pragma-3.c: New test.

Diff:
---
 .../c-c++-common/cpp/diagnostic-pragma-3.c         | 37 ++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-3.c b/gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-3.c
new file mode 100644
index 000000000000..459dcec73b32
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/diagnostic-pragma-3.c
@@ -0,0 +1,37 @@
+/* This is like diagnostic-pragma-2.c, but handles the case where everything
+   is wrapped inside a macro, which previously caused additional issues tracked
+   in PR preprocessor/82335.  */
+
+/* { dg-do compile } */
+/* { dg-additional-options "-save-temps -Wattributes -Wtype-limits" } */
+
+#define B _Pragma("GCC diagnostic push") \
+          _Pragma("GCC diagnostic ignored \"-Wattributes\"")
+#define E _Pragma("GCC diagnostic pop")
+
+#define X() B int __attribute((unknown_attr)) x; E
+#define Y   B int __attribute((unknown_attr)) y; E
+#define WRAP(x) x
+
+void test1(void)
+{
+  WRAP(X())
+  WRAP(Y)
+}
+
+/* Additional test provided on the PR.  */
+#define PRAGMA(...) _Pragma(#__VA_ARGS__)
+#define PUSH_IGN(X) PRAGMA(GCC diagnostic push) PRAGMA(GCC diagnostic ignored X)
+#define POP() PRAGMA(GCC diagnostic pop)
+#define TEST(X, Y) \
+  PUSH_IGN("-Wtype-limits") \
+  int Y = (__typeof(X))-1 < 0; \
+  POP()
+
+int test2()
+{
+  unsigned x;
+  TEST(x, i1);
+  WRAP(TEST(x, i2))
+  return i1 + i2;
+}