target/10395: sse2 datatype is not 16bytes aligned in threaded code

[vgrebinski at yahoo dot com]

>Number:         10395
>Category:       target
>Synopsis:       sse2 types are incorrectly aligned causing crash in multi-threaded apps
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 13 22:46:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Vladimir Grebinskiy
>Release:        3.3 20030410 (prerelease)
>Organization:
>Environment:
System: Linux vag 2.4.21-pre5 #2 Sun Mar 2 00:28:31 EST 2003 i686 unknown unknown GNU/Linux
Architecture: i686

	
host: i386-pc-linux-gnu
build: i386-pc-linux-gnu
target: i386-pc-linux-gnu
configured with: /build/packages/gcc/snap/gcc-snapshot-20030410/src/configure -v --enable-languages=c,c++,java,f77,pascal,objc,ada --prefix=/usr/lib/gcc-snapshot --infodir=/share/info --mandir=/share/man --enable-shared --with-system-zlib --enable-nls --without-included-gettext --enable-__cxa_atexit --enable-clocale=gnu --enable-java-gc=boehm --enable-java-awt=xlib --with-cpp-install-dir=bin --enable-multilibs --enable-objc-gc i386-linux
>Description:
support for sse2 instruction is an important addtion to gcc-3.3. Unfortunately, code generated for functions called via pthread_create() does not provide 16bytes alignment for local sse2 data, which causes crash when these variables are used. 
>How-To-Repeat:
The following short program demonstrates problem. The second call to function "f" shows that variable is not aligned to 16 bytes:

/* *** start ***/
#include <pthread.h>
#include <stdio.h>
#include <assert.h>

#include <xmmintrin.h>
#include <mmintrin.h>

#ifdef __ICC
#include <emmintrin.h>
#endif

void * f(void *p)
{
  int x = (p == NULL) ? 0 : * (int *) p;
  __m128i s;
  printf("&x = %p &s= %p\n", &x, &s);
  return NULL;
}

int main(int argc, char ** argv)
{
  pthread_t th;

  f(& argc);
  assert(pthread_create(& th, NULL, f, &argc)==0);
  assert(pthread_join(th, NULL)==0);
  return 0;
}

/* ***end *** /

$ /usr/lib/gcc-snapshot/bin/gcc -pthread -msse2 gcc_test.c -o gcc_test.LINUX
$ ./gcc_test.LINUX
&x = 0xbffffb6c &s= 0xbffffb50
&x = 0xbf7ffae8 &s= 0xbf7ffacc <---- error 

>Fix:
don't know

>Release-Note:
>Audit-Trail:
>Unformatted: