http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49519
--- Comment #5 from Yukhin Kirill <kirill.yukhin at intel dot com> 2011-06-29
12:24:25 UTC ---
Problem here is that GCC incorrectly stores arguments to stack in case of
tail-call opt.
Here is snippet
movl 40(%esp), %eax
movl %eax, 28(%esp)
movl 36(%esp), %esi
movl %esi, 24(%esp)
movl 32(%esp), %esi
movl %esi, 20(%esp)
movl %eax, 16(%esp)
Argument from 28(%esp) is not copied to 28(%esp) at all.
Correct sequence must be (semantically) like that:
movl 40(%esp), %esi ; <----- Use esi to move memory
movl 28(%esp), %eax ; <----- Save overlapping value
movl %esi, 28(%esp)
movl 36(%esp), %esi
movl %esi, 24(%esp)
movl 32(%esp), %esi
movl %esi, 20(%esp)
movl %eax, 16(%esp) ; <----- Store saved value
Working toward the patch
