[Intel-gfx] [PATCH] drm/i915: More reasonable memcpy unroll in i915_gem_swizzle_page

[Jani Nikula]

On Mon, 19 Dec 2016, Joonas Lahtinen <joonas.lahtinen at linux.intel.com> wrote:
> On ma, 2016-12-19 at 09:19 +0000, Tvrtko Ursulin wrote:
>> +++ b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
>> @@ -631,9 +631,9 @@ i915_gem_swizzle_page(struct page *page)
>>  	vaddr = kmap(page);
>>  
>>  	for (i = 0; i < PAGE_SIZE; i += 128) {
>> -		memcpy(temp, &vaddr[i], 64);
>> +		memcpy(&temp[0], &vaddr[i], 64);
>>  		memcpy(&vaddr[i], &vaddr[i + 64], 64);
>> -		memcpy(&vaddr[i + 64], temp, 64);
>> +		memcpy(&vaddr[i + 64], &temp[0], 64);
>
> This reeks of GCC bug badly. So I would not apply as next time the bug
> could be into the another direction.

Agreed. Please file a bug over at https://gcc.gnu.org/bugs/

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center