[PATCH] diagnostics: Add test for fixed _Pragma location issue [PR91669]

[Lewis Hyatt <lhyatt@gmail.com>]

This PR related to _Pragma locations and diagnostic pragmas was fixed by a
combination of r10-325 and r13-1596. Add missing test coverage.

gcc/testsuite/ChangeLog:

	PR c/91669
	* c-c++-common/pr91669.c: New test.
---

Notes:
    Hello-
    
    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91669#c4
    
    The above PR was already fixed, but I'd like to add missing test coverage
    before closing it. Does this look OK please? Thanks!
    
    -Lewis

 gcc/testsuite/c-c++-common/pr91669.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 gcc/testsuite/c-c++-common/pr91669.c

diff --git a/gcc/testsuite/c-c++-common/pr91669.c b/gcc/testsuite/c-c++-common/pr91669.c
new file mode 100644
index 00000000000..1070751ed2e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr91669.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-Wreturn-type" } */
+
+/* The location of the right brace within the macro expansion can be an adhoc
+   location, because the frontend attached custom data to it.  In order for the
+   diagnostic pragma to correctly understand that the diagnostic pop occurs
+   after the function and not before, linemap_location_before_p needs to handle
+   adhoc locations within a macro map, which was broken until fixed by r10-325.
+   Verify that we get it right, both when the brace is a macro token and when it
+   is part of the macro expansion.  */
+
+#define ENDFUNC1 \
+  _Pragma("GCC diagnostic push") \
+  _Pragma("GCC diagnostic ignored \"-Wreturn-type\"") \
+  } /* { dg-bogus {-Wreturn-type} } */ \
+  _Pragma("GCC diagnostic pop")
+
+int f1 () {
+ENDFUNC1 /* { dg-bogus {in expansion of macro 'ENDFUNC1' } } */
+
+#define ENDFUNC2(term) \
+  _Pragma("GCC diagnostic push") \
+  _Pragma("GCC diagnostic ignored \"-Wreturn-type\"") \
+  term /* { dg-bogus {in definition of macro 'ENDFUNC2'} } */ \
+  _Pragma("GCC diagnostic pop")
+
+int f2 () {
+ENDFUNC2(}) /* { dg-bogus {-Wreturn-type} } */