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.
--
H.J.
