Command line:
gcc -fschedule-insns vararg-1.c && ./a.out
Testcase can be further reduced to:
----------- testcase.c -----------
int foo(int i, ...) {
return i;
}
int main() {
return foo(0, 0.0);
}
----------------------------------
I am not sure the testcase is valid, but I can't find any proof it isn't.
"If access to the varying arguments is desired, the called function shall
declare an object (...) having type va_list." is the most related sentence in
the C99 TC3 draft, but it doesn't say what to do when 'access to varying
arguments isn't desired'.
Tested revisions:
r157965 - crash
4.4.3 - crash
4.3.4, 4.2.4, 4.1.2, 3.4.6, 3.3.6 - OK
Output:
$ gcc-4.5.0-alpha20100401 -fschedule-insns testcase.c && ./a.out
Segmentation fault
The problem is unaligned access with movaps:
foo:
pushq %rbp #
movq %rsp, %rbp #,
pushq %rbx #
subq $64, %rsp #,
movzbl %al, %eax #, tmp61
leaq -9(%rbp), %rbx #, tmp62
...
movaps %xmm0, -127(%rbx) #,
access is aligned to 8-byte boundary, not 16-byte
when -fschedule-insns is not used, "leaq -9(%rbp), %rbx" is changed to "leaq
-1(%rbp), %rdx", and the access is aligned correctly
--
Summary: -fschedule-insns causes FAIL: gcc.target/i386/vararg-1.c
execution test
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: zsojka at seznam dot cz
GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43668
