>>> On 27.06.19 at 12:22, <ubiz...@gmail.com> wrote:
> On Thu, Jun 27, 2019 at 11:10 AM Jan Beulich <jbeul...@suse.com> wrote:
>>
>> >>> On 27.06.19 at 11:03, wrote:
>> > With just an "m" constraint misaligned memory operands won't be forced
>> > into a register, and hence cause #GP. So far this was guaranteed only
>> > in the case that CVT{,T}PD2DQ were chosen (which looks to be the case on
>> > x86-64 only).
>> >
>> > Instead of switching the second alternative to Bm, use just m on the
>> > first and replace nonimmediate_operand by vector_operand.
>>
>> While doing this and the others where I'm also replacing Bm by uses of
>> vector_operand, I've started wondering whether Bm couldn't (and then
>> shouldn't) be dropped altogether, replacing it everywhere by "m"
>> combined with vector_operand (or vector_memory_operand when
>> register operands aren't allowed anyway).
>
> No. Register allocator will propagate unaligned memory in non-AVX
> case, which is not allowed with vector_operand.
I'm afraid I don't understand: Unaligned SIMD memory accesses will
generally fault in non-AVX mode, so such propagation would seem
wrong to me and hence would seem to be correctly not allowed.
Furthermore both vector_operand and Bm resolve to the same
vector_memory_operand. The TARGET_AVX check actually is inside
vector_memory_operand, i.e. affects both the same way.
Jan
