http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60926
Bug ID: 60926
Summary: Compiler doesn't properly align stack pointer
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: trivial
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: gidici61 at gmail dot com
Assembly code of the sample C code:
int g2(int p1) { return p1; }
int g1(int p1) { return g2(p1); }
int main() { return g1(65); }
when compiled [¹] on Debian wheezy using gcc v.4.7.2 shows that register rsp is
not 16 byte aligned before calling g2():
g1:
pushq %rbp
movq %rsp, %rbp
subq $8, %rsp ; why 8?
movl %edi, -4(%rbp)
movl -4(%rbp), %eax
movl %eax, %edi
call g2
leave
ret
[¹] gcc -S filename.c
