Re: PATCH: PR target/52146: [x32] - Wrong code to access addresses 0x80000000 to 0xFFFFFFFF

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, Feb 10, 2012 at 9:55 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Fri, Feb 10, 2012 at 6:42 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>
>>> Since constant address in x32 is signed extended to 64bit, negative
>>> displacement without base nor index is out of range.  OK for trunk?
>>>
>>
>> Here is a different patch.
>>
>> H.J.
>> ---
>> gcc/
>>
>> 2012-02-10  Uros Bizjak  <ubizjak@gmail.com>
>>
>>        PR target/52146
>>        * config/i386/i386.c (ix86_legitimate_address_p): Disallow
>>        negative constant address for x32.
>>
>> gcc/testsuite/
>>
>> 2012-02-10  H.J. Lu  <hongjiu.lu@intel.com>
>>
>>        PR target/52146
>>        * gcc.target/i386/pr52146.c: New.
>>
>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> index 009dd53..8f4e72e 100644
>> --- a/gcc/config/i386/i386.c
>> +++ b/gcc/config/i386/i386.c
>> @@ -11932,6 +11932,13 @@ ix86_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
>>   rtx base, index, disp;
>>   HOST_WIDE_INT scale;
>>
>> +  /* Since constant address in x32 is signed extended to 64bit,
>> +     we have to prevent addresses from 0x80000000 to 0xffffffff.  */
>> +  if (TARGET_X32
>> +      && CONST_INT_P (addr)
>> +      && val_signbit_known_set_p (SImode, INTVAL (addr)))
>
> As said in the PR, val_signbit_known_set_p is a bit overkill. Please
> use INTVAL (addr) < 0, it works as well.
>
>> +++ b/gcc/testsuite/gcc.target/i386/pr52146.c
>> @@ -0,0 +1,17 @@
>> +/* { dg-do compile { target { { i?86-*-linux* x86_64-*-linux* } && { ! { ia32 } } } } } */
>
> we _are_ in x86 directory, so:
>
> /* { dg-do compile { target { ! { ia32 } } } }  */
>
>> +/* { dg-options "-O2 -mx32" } */
>> +
>> +void test1() {
>> +  int* apic_tpr_addr = (int *)0xfee00080;
>> +  *apic_tpr_addr += 4;
>> +}
>> +void test2() {
>> +  volatile int* apic_tpr_addr = (int *)0xfee00080;
>> +  *apic_tpr_addr = 0;
>
> No need for volatile.
>
>> +}
>> +void test3() {
>> +  volatile int* apic_tpr_addr = (int *)0x7fffffff;
>> +  *apic_tpr_addr = 0;
>> +}
>
> test2 is enough. No need to test what worked OK.
>
>> +
>> +/* { dg-final { scan-assembler-not "-18874240" } } */
>
> Please also reformat the test to GNU coding standards.
>
> Patch is OK for 4.7 and 4.6 after bootstrap and regression test on x32 target.

I checked it into 4.7 and will backport to my x32 4.6 branch.

Thanks.

-- 
H.J.