"H.J. Lu" <hjl.to...@gmail.com> writes:
> On Sat, Feb 1, 2014 at 2:28 AM, Richard Sandiford
> <rdsandif...@googlemail.com> wrote:
>> "H.J. Lu" <hjl.to...@gmail.com> writes:
>>> On Thu, Jan 30, 2014 at 10:43 AM, Richard Sandiford
>>> <rdsandif...@googlemail.com> wrote:
>>>> Hi H.J.,
>>>>
>>>> "H.J. Lu" <hjl.to...@gmail.com> writes:
>>>>> diff --git a/gcc/testsuite/gcc.dg/pr59605.c
>>>>> b/gcc/testsuite/gcc.dg/pr59605.c
>>>>> new file mode 100644
>>>>> index 0000000..4556843
>>>>> --- /dev/null
>>>>> +++ b/gcc/testsuite/gcc.dg/pr59605.c
>>>>> @@ -0,0 +1,55 @@
>>>>> +/* { dg-do run } */
>>>>> +/* { dg-options "-O2" } */
>>>>> +/* { dg-additional-options "-minline-stringops-dynamically" { target
>>>>> { i?86-*-* x86_64-*-* } } } */
>>>>> +
>>>>> +extern void abort (void);
>>>>> +
>>>>> +#define MAX_OFFSET (sizeof (long long))
>>>>> +#define MAX_COPY (1024 + 8192)
>>>>> +#define MAX_EXTRA (sizeof (long long))
>>>>> +
>>>>> +#define MAX_LENGTH (MAX_OFFSET + MAX_COPY + MAX_EXTRA)
>>>>> +
>>>>> +static union {
>>>>> + char buf[MAX_LENGTH];
>>>>> + long long align_int;
>>>>> + long double align_fp;
>>>>> +} u;
>>>>> +
>>>>> +char A[MAX_LENGTH];
>>>>> +
>>>>> +int
>>>>> +main ()
>>>>> +{
>>>>> + int off, len, i;
>>>>> + char *p, *q;
>>>>> +
>>>>> + for (i = 0; i < MAX_LENGTH; i++)
>>>>> + A[i] = 'A';
>>>>> +
>>>>> + for (off = 0; off < MAX_OFFSET; off++)
>>>>> + for (len = 1; len < MAX_COPY; len++)
>>>>> + {
>>>>> + for (i = 0; i < MAX_LENGTH; i++)
>>>>> + u.buf[i] = 'a';
>>>>> +
>>>>> + p = __builtin_memcpy (u.buf + off, A, len);
>>>>> + if (p != u.buf + off)
>>>>> + abort ();
>>>>> +
>>>>> + q = u.buf;
>>>>> + for (i = 0; i < off; i++, q++)
>>>>> + if (*q != 'a')
>>>>> + abort ();
>>>>> +
>>>>> + for (i = 0; i < len; i++, q++)
>>>>> + if (*q != 'A')
>>>>> + abort ();
>>>>> +
>>>>> + for (i = 0; i < MAX_EXTRA; i++, q++)
>>>>> + if (*q != 'a')
>>>>> + abort ();
>>>>> + }
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>
>>>> The innermost loop bodies are executed over 6x10⁸ times on most targets
>>>> and so the test times out for me when using the GDB MIPS simulator.
>>>> I'm not sure what the best fix is though. E.g.:
>>>>
>>>> 1. It looks like the PR was for a compile-time failure rather than a
>>>> run-time
>>>> failure, so one option might be to drop it to dg-do compile. That'd
>>>> lose
>>>> a nice executable conformance test though. I don't like this option.
>>>>
>>>> 2. We could drop it to dg-do compile for simulator targets only.
>>>> That's still
>>>> lose some conformance testing for simulator targets.
>>>>
>>>> 3. We could use a smaller MAX_COPY for simulator targets, which is
>>>> typically
>>>> how check_effective_target_simulator is used. I'm not sure
>>>> whether having
>>>> a smaller MAX_COPY would defeat the original ICE test though.
>>>>
>>>> 4. We could split the test into two, a dg-do compile one and a dg-do
>>>> run one.
>>>> We could then do (3) on the run one.
>>>>
>>>> But there are probably other alternatives too.
>>>>
>>>> I'm willing to do the patch, but has anyone got any suggestions for
>>>> what would be best?
>>>>
>>>
>>> Can you reduce the loop count and still trigger the bug without
>>> the fix?
>>
>> Not by much. AFAICT the lowest MAX_COPY for which the ICE still triggers
>> is 8194, which only reduces the 6x10⁸ to something over 5.38x10⁸.
>>
>> So I think it's a choice between (2) and (4). How about the patch below?
>> Tested on mipsisa64-sde-elf and x86_64-linux-gnu. Both tests failed before
>> the i386.c fix.
>>
>> Thanks,
>> Richard
>>
>>
>> gcc/testsuite/
>> * gcc.dg/pr59605.c: Convert to a compile test. Protect MAX_COPY
>> definition with an ifdef.
>> * gcc.dg/pr59605-2.c: New test.
>>
>> Index: gcc/testsuite/gcc.dg/pr59605-2.c
>> ===================================================================
>> --- /dev/null 2014-01-30 08:06:21.701666182 +0000
>> +++ gcc/testsuite/gcc.dg/pr59605-2.c 2014-02-01 10:25:08.674430391 +0000
>> @@ -0,0 +1,6 @@
>> +/* { dg-do run } */
>> +/* { dg-options "-O2" } */
>> +/* { dg-additional-options "-DMAX_COPY=1025" { target simulator } } */
>> +/* { dg-additional-options "-minline-stringops-dynamically" { target {
>> i?86-*-* x86_64-*-* } } } */
>> +
>> +#include "pr59605.c"
>> Index: gcc/testsuite/gcc.dg/pr59605.c
>> ===================================================================
>> --- gcc/testsuite/gcc.dg/pr59605.c 2014-02-01 10:13:26.176018090 +0000
>> +++ gcc/testsuite/gcc.dg/pr59605.c 2014-02-01 10:24:22.713003808 +0000
>> @@ -1,11 +1,13 @@
>> -/* { dg-do run } */
>> +/* { dg-do compile } */
>> /* { dg-options "-O2" } */
>> /* { dg-additional-options "-minline-stringops-dynamically" { target {
>> i?86-*-* x86_64-*-* } } } */
>>
>> extern void abort (void);
>>
>> #define MAX_OFFSET (sizeof (long long))
>> +#ifndef MAX_COPY
>> #define MAX_COPY (1024 + 8192)
>> +#endif
>> #define MAX_EXTRA (sizeof (long long))
>>
>> #define MAX_LENGTH (MAX_OFFSET + MAX_COPY + MAX_EXTRA)
>
> That is fine with me.
Thanks. Is it OK to commit?
Richard
