On Tue, Dec 2, 2014 at 5:25 AM, Uros Bizjak <[email protected]> wrote:
> On Sat, Nov 29, 2014 at 3:00 PM, H.J. Lu <[email protected]> wrote:
>> When searching for an usable algorithm with -minline-all-stringops,
>> decide_alg stops when it sees libcall even if there is a usable
>> algorithm. It goes into an infinite loop. This patch changes
>> decide_alg to stop searching only if there aren't any usable algorithms.
>> Testd on Linux/x86-64. OK for trunk.
>>
>>
>> H.J.
>> ----
>> gcc/
>>
>> 2014-11-29 H.J. Lu <[email protected]>
>>
>> PR target/64108
>> * config/i386/i386.c (decide_alg): Stop only if there aren't
>> any usable algorithms.
>>
>> gcc/testsuite/
>>
>> 2014-11-29 H.J. Lu <[email protected]>
>>
>> PR target/64108
>> * gcc.target/i386/memset-strategy-2.c: New test.
>
> OK with a change below. Please wait a couple of days before
> backporting the fix - the fix looks kind of obvious, but this part of
> the code is somehow complex and has biten us in the past.
Will do.
> Thanks,
> Uros.
>
>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> index 2493130..d789635 100644
>> --- a/gcc/config/i386/i386.c
>> +++ b/gcc/config/i386/i386.c
>> @@ -24464,7 +24464,9 @@ decide_alg (HOST_WIDE_INT count, HOST_WIDE_INT
>> expected_size,
>> *noalign = alg_noalign;
>> return alg;
>> }
>> - break;
>> + /* Stop only if there aren't any usable algorithms. */
>> + if (!any_alg_usable_p)
>> + break;
>
> Please use "else if ..." and remove unneded argument. IMO, the code
> speaks for itself.
Which unneeded argument to remove? All arguments of decide_alg are
used.
>> }
>> else if (alg_usable_p (candidate, memset))
>> {
>> diff --git a/gcc/testsuite/gcc.target/i386/memset-strategy-2.c
>> b/gcc/testsuite/gcc.target/i386/memset-strategy-2.c
>> new file mode 100644
>> index 0000000..aafa54d
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/i386/memset-strategy-2.c
>> @@ -0,0 +1,10 @@
>> +/* PR target/64108 */
>> +/* { dg-do compile } */
>> +/* { dg-options "-O2 -march=atom -mmemset-strategy=libcall:-1:align
>> -minline-all-stringops" } */
>> +
>> +char a[2048];
>> +void t (void)
>> +{
>> + __builtin_memset (a, 1, 2048);
>> +}
>> +
--
H.J.
