Take the following code:
#include <stdarg.h>
int
foo (int a, ...)
{
va_list ap;
va_list ap1;
va_list ap2;
va_list ap3;
va_list ap4;
va_start (ap, a);
int b;
ap1 = ap;
ap2 = ap1;
do {
ap1 = ap2;
b = va_arg (ap1, int);
ap2 = ap1;
} while (b > 10);
return a + b;
}
int
main ()
{
if (foo (1, 2, 3) != 3)
abort ();
return 0;
}
---
With -O1, we get an abort as the argruments at not saved to the stack at all.
This is reduced/changed from 20000519-1.c which was exposed by RTH's patch:
* c-common.c (handle_mode_attribute): When not modifying in place,
create subtypes for enumerations.
(sync_resolve_return): Use TYPE_MAIN_VARIANT.
* gimplify.c (create_tmp_from_val): Likewise.
--
Summary: [4.1 Regression] tree-stdarg.c causes wrong code, not
tracking va_list variable correctly
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: critical
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pinskia at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-darwin,powerpc-aix
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24126
