[Bug c/36014] New: gcc produces broken code when -mregparm=3

[simon at sxw dot org dot uk]

gcc produces broken function entry code when building code with incomplete
prototypes, and -mregparm=3.

The following test case illustrates the problem ...

extern int printf (const char *, ...) __attribute__ ((regparm(0)));

static int test();

int main(int argc, char **argv) {

  test(0,1,2,3,4,5,6,7);
}

static int test(int a, int b, int c, int d, int e, int f, int g, int h) {
  if (a != 0 || b != 1 || c != 2) {
    printf("Wrong: Got (%p, %p, %p, %p, %p, %p, %p, %p)", a, b, c, d, e, f, g,
h);
  }

  return 1;
}

When built with gcc -mregparm=3, and run, this produces:

Wrong: Got (0x1, 0xbfc96430, 0xbfc96410, (nil), 0x1, 0x2, 0x3, 0x4)


-- 
           Summary: gcc produces broken code when -mregparm=3
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: simon at sxw dot org dot uk
 GCC build triplet: i386-redhat-linux
  GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36014