[Bug target/52352] [x32] - Wrong code to access addresses 0x80000000 to 0xFFFFFFFF using registers

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52352

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> 2012-02-24 20:03:59 UTC ---
(In reply to comment #12)
> (In reply to comment #11)
> 
> > I checked a similar fix into hjl/x32/addr32, hjl/x32/gcc-4_6-branch and
> > hjl/x32/gcc-4_6-branch+mx32 branches. I also added "I" code to print
> > constant address as positive 32bit integer for x32:
> 
> I think we can simply disable these two patterns on x32.
> 
> This is with disabled patterns:
> 
> 0000000000000000 <x32_O3_main>:
>    0:   b8 00 00 e0 fe          mov    $0xfee00000,%eax
>    5:   8b 00                   mov    (%rax),%eax
>    7:   a8 01                   test   $0x1,%al
>    9:   74 01                   je     c <x32_O3_main+0xc>
>    b:   90                      nop
>    c:   b8 00 00 e0 fe          mov    $0xfee00000,%eax
>   11:   8b 50 08                mov    0x8(%rax),%edx
>   14:   89 50 04                mov    %edx,0x4(%rax)
>   17:   c3                      retq   
> 
> and with enabled patterns:
> 
> 0000000000000000 <x32_O3_main>:
>    0:   a1 00 00 e0 fe 00 00    movabs 0xfee00000,%eax
>    7:   00 00 
>    9:   a8 01                   test   $0x1,%al
>    b:   74 01                   je     e <x32_O3_main+0xe>
>    d:   90                      nop
>    e:   a1 08 00 e0 fe 00 00    movabs 0xfee00008,%eax
>   15:   00 00 
>   17:   a3 04 00 e0 fe 00 00    movabs %eax,0xfee00004
>   1e:   00 00 
>   20:   c3                      retq   
> 
> There is simply no need for movabs from/to mem, since there is no 64bit
> addresses. And code size is horrible (and I bet that the former code runs
> faster).

I think it is a good idea.