[Bug middle-end/44321] New: attribute warn_unused_result fails under inlining.

["davek at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

In the (to-be) attached testcase, GCC warns about an unused result when the
return value of the function is ignored, or cast to void, but it fails to warn
when the cast-to-void is hidden inside an inline function, like so:

$ cat -n wur.c
     1
     2  static inline void ignore_value (int i) { (void) i; }
     3
     4  extern int foo (void) __attribute__ ((warn_unused_result));
     5
     6  void bar1 (void)
     7  {
     8    foo ();
     9  }
    10
    11  void bar2 (void)
    12  {
    13    (void) foo ();
    14  }
    15
    16  void bar3 (void)
    17  {
    18    ignore_value (foo ());
    19  }

$ gcc-4 -c wur.c  -o wur.o --save-temps -W -Wall -Wextra
wur.c: In function 'bar2':
wur.c:13:3: warning: ignoring return value of 'foo', declared with attribute
war
n_unused_result [-Wunused-result]
wur.c: In function 'bar1':
wur.c:8:7: warning: ignoring return value of 'foo', declared with attribute
warn
_unused_result [-Wunused-result]

This happens at all -O levels.  I haven't filled in the host/target/build
triplets because I don't suppose it is in any way specific to any of them.

BTW, it's interesting that the warnings come out in reverse order, is that
supposed to happen?


-- 
           Summary: attribute warn_unused_result fails under inlining.
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: davek at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44321