[Bug c/25284] New: incorrect double value returned from function testo() called from main().

[Bug c/25284] New: incorrect double value returned from function testo() called from main().

[gnassre at earthlink dot net]

inside main(), a call is made to function testo() which simply returns a
double(1415.149).  The correct double value is returned only if main.c has
#include <f.h>, which is where testo() is declared.

I've compiled two versions of this program, with and without the include line,
withinclude.a.out and withoutinclude.a.out, respectively.  The assembled code
varies slightly between the two, withoutinclude.a.out having the following
extra three lines shown below (with xxx): 

        realnum=testo();
 8048384:       e8 2b 00 00 00          call   80483b4 <testo>
 8048389:       50                      push   %eax                    xxx
 804838a:       db 04 24                fildl  (%esp)                  xxx
 804838d:       8d 64 24 04             lea    0x4(%esp),%esp          xxx
 8048391:       dd 5d f8                fstpl  0xfffffff8(%ebp)         


fildl takes the pushed value (0xa) and stores it onto the floating point stack
and then fetched by fstpl, which is then stored in realnum.


This code does NOT get generated if there is an #include <f.h> in main.c


-- 
           Summary: incorrect double value returned from function testo()
                    called from main().
           Product: gcc
           Version: 3.4.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gnassre at earthlink dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284

[Bug c/25284] incorrect double value returned from function testo() called from main().

[gnassre at earthlink dot net]

------- Comment #2 from gnassre at earthlink dot net  2005-12-06 19:40 -------
Created an attachment (id=10422)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10422&action=view)
output of gcc -v 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284

[Bug c/25284] incorrect double value returned from function testo() called from main().

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2005-12-06 19:40 -------
The C standard says that if a function is not declared (prototyped) then
implicately it returns the type of int.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284

[Bug c/25284] incorrect double value returned from function testo() called from main().

[gnassre at earthlink dot net]

------- Comment #4 from gnassre at earthlink dot net  2005-12-06 19:41 -------
Created an attachment (id=10424)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10424&action=view)
main() function definition file from gcc --save-temps


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284

[Bug c/25284] incorrect double value returned from function testo() called from main().

[gnassre at earthlink dot net]

------- Comment #3 from gnassre at earthlink dot net  2005-12-06 19:41 -------
Created an attachment (id=10423)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10423&action=view)
testo() function definition file from gcc --save-temps


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284

[Bug c/25284] incorrect double value returned from function testo() called from main().

[gnassre at earthlink dot net]

------- Comment #5 from gnassre at earthlink dot net  2005-12-06 19:45 -------
(In reply to comment #1)
> The C standard says that if a function is not declared (prototyped) then
> implicately it returns the type of int.
> 

ok thanks, that makes sense =)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25284