[Bug target/52876] [x32] - Sign extend 32 to 64bit then clear upper 32bits fails O1 or higher

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52876

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> 2012-04-05 13:42:30 UTC ---
The reason why GCC 4.6 works is it uses SImode for Pmode.
On trunk, I got

[hjl@gnu-6 pr52876]$ cat x.i
long long li;

long long testfunc(void* addr) __attribute__ ((noinline));
long long testfunc(void* addr)
{
  li = (long long)(int)addr;

  // next line is important, if the address from pv
  // has been sign extended with leading ONEs
  li &= 0xffffffff;

  return li;
}
[hjl@gnu-6 pr52876]$ /export/build/gnu/gcc-x32/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-x32/build-x86_64-linux/gcc/ -S -o x.s -mx32 -O  x.i
-maddress-mode=long
[hjl@gnu-6 pr52876]$ cat x.s
    .file    "x.i"
    .text
    .globl    testfunc
    .type    testfunc, @function
testfunc:
.LFB0:
    .cfi_startproc
    movslq    %edi, %rax
    movq    %rax, li(%rip)
    ret
    .cfi_endproc
.LFE0:
    .size    testfunc, .-testfunc
    .comm    li,8,8
    .ident    "GCC: (GNU) 4.8.0 20120403 (experimental)"
    .section    .note.GNU-stack,"",@progbits
[hjl@gnu-6 pr52876]$ /export/build/gnu/gcc-x32/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-x32/build-x86_64-linux/gcc/ -S -o x.s -mx32 -O  x.i
-maddress-mode=short
[hjl@gnu-6 pr52876]$ cat x.s
    .file    "x.i"
    .text
    .globl    testfunc
    .type    testfunc, @function
testfunc:
.LFB0:
    .cfi_startproc
    movq    %rdi, %rax
    movq    %rdi, li(%rip)
    ret
    .cfi_endproc
.LFE0:
    .size    testfunc, .-testfunc
    .comm    li,8,8
    .ident    "GCC: (GNU) 4.8.0 20120403 (experimental)"
    .section    .note.GNU-stack,"",@progbits
[hjl@gnu-6 pr52876]$ 

-maddress-mode=long generates the wrong code.  We have a
POINTERS_EXTEND_UNSIGNED bug.