Re: c/7689: Bad code generated when function sometimes does not return

Re: c/7689: Bad code generated when function sometimes does not return

[ebotcazou]

Synopsis: Bad code generated when function sometimes does not return

State-Changed-From-To: open->feedback
State-Changed-By: ebotcazou
State-Changed-When: Tue Nov 19 03:52:21 2002
State-Changed-Why:
    I can't reproduce the problem with the testcase you provided (using -Os, -O0, -O1, -O2, -O3). Could you specify the options you passed to the compiler ?

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7689

Re: c/7689: Bad code generated when function sometimes does not return

[neroden]

Synopsis: Bad code generated when function sometimes does not return

State-Changed-From-To: feedback->closed
State-Changed-By: neroden
State-Changed-When: Sun Feb 23 21:29:36 2003
State-Changed-Why:
    Can't reproduce, no feedback 3 mo.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7689

c/7689: Bad code generated when function sometimes does not return

[hpa]

>Number:         7689
>Category:       c
>Synopsis:       Bad code generated when function sometimes does not return
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Aug 22 14:56:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     hpa@transmeta.com
>Release:        unknown-1.0
>Organization:
>Environment:
i386-redhat-linux Linux RedHat Beta 7.3.94 ("null")

Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --host=i386-redhat-linux --with-system-zlib --enable-__cxa_atexit
Thread model: posix
gcc version 3.2 (Red Hat Linux Rawhide 3.2-1)

>Description:
The included code is from a real-life program.  Here, obviously, the die() function never returns, and so the programmer has not bothered to put a return at the end of the function.  However, when compiled with gcc 3.2, the compiler does not set the return value register (%eax) even in the case when the function *DOES* return (strcmp() returns zero.)
>How-To-Repeat:
The test case I have looks like: (preprocessed version included in attachment.)

#include <string.h>

struct rom {
  char *name;
  int data;
};

typedef struct rom *rom_t;

typedef int boolean;

extern void assert_rom_layouts(void);
extern int verify_rom_sanity(rom_t, boolean);

extern void errorf(char *, ...);
extern void die(void);

typedef struct rom_file_S
{
    char * name;
    rom_t * roms;
    unsigned s_roms;
    unsigned n_roms;
} rom_file_s, * rom_file_t;

extern rom_file_s rom_file;

extern char *parse_file;

rom_t
find_rom (char * model, boolean complete)
{
    unsigned int ctr;
    rom_t rom;

    assert_rom_layouts ();

    for (ctr = 0; (ctr < (rom_file.n_roms)); ctr++)
    {
        rom = (rom_file.roms[ctr]);
        if ((strcmp ((rom->name), model)) == 0)
        {
            verify_rom_sanity (rom, complete);
            return (rom);
        }
    }
    
    errorf ("ROM layout \"%s\" not found in \"%s\".\n", model, parse_file);
    die ();
}
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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