On Sun, Jun 30, 2013 at 11:47 AM, Jan Hubicka <hubi...@ucw.cz> wrote:
>>
>> What target flags are enabled by AVX? Assumming that all target flags are
>> positive seems incorrect to me (like -mno-red-zone function can not be
>> inlined
>> into -mred-zone). Does those conditionally enabled AVX codegen flags have
>> any
>
> Actually -mred-zone seems right, but stuff like -msseregparm will probably
> break?
>
> Honza
>
>> effect when AVX is disabled? Perhaps we can set them unconditionally?
The issue is with (config/i386.c, ix86_option_override_internal):
if (TARGET_AVX)
{
/* When not optimize for size, enable vzeroupper optimization for
TARGET_AVX with -fexpensive-optimizations and split 32-byte
AVX unaligned load/store. */
if (!optimize_size)
{
if (flag_expensive_optimizations
&& !(target_flags_explicit & MASK_VZEROUPPER))
target_flags |= MASK_VZEROUPPER;
if ((x86_avx256_split_unaligned_load & ix86_tune_mask)
&& !(target_flags_explicit & MASK_AVX256_SPLIT_UNALIGNED_LOAD))
target_flags |= MASK_AVX256_SPLIT_UNALIGNED_LOAD;
if ((x86_avx256_split_unaligned_store & ix86_tune_mask)
&& !(target_flags_explicit & MASK_AVX256_SPLIT_UNALIGNED_STORE))
target_flags |= MASK_AVX256_SPLIT_UNALIGNED_STORE;
/* Enable 128-bit AVX instruction generation
for the auto-vectorizer. */
if (TARGET_AVX128_OPTIMAL
&& !(target_flags_explicit & MASK_PREFER_AVX128))
target_flags |= MASK_PREFER_AVX128;
}
These are all tuning flags that are applicable to AVX only. They
depend on AVX, so can be probably enabled unconditionally.
Uros.
