On Thu, May 11, 2017 at 2:48 PM, Richard Biener <rguent...@suse.de> wrote:
> On Thu, 11 May 2017, Rainer Orth wrote:
>
>> Hi Richard,
>>
>> > On Mon, 24 Apr 2017, Richard Biener wrote:
>> >>
>> >> One issue in PR79201 is that we don't sink pure/const calls which is
>> >> what the following simple patch fixes.
>> >>
>> >> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>> >
>> > Needed some gimple_assign_lhs -> gimple_get_lhs adjustments and
>> > adjustment of gcc.target/i386/pr22152.c where we now sink the
>> > assignment out of the pointless loop. Not sure what the original
>> > bug was about (well, reg allocation) so I simply disabled sinking
>> > for it.
>> >
>> > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
>> >
>> > Richard.
>> >
>> > 2017-04-25 Richard Biener <rguent...@suse.de>
>> >
>> > PR tree-optimization/79201
>> > * tree-ssa-sink.c (statement_sink_location): Handle calls.
>> >
>> > * gcc.dg/tree-ssa/ssa-sink-16.c: New testcase.
>> > * gcc.target/i386/pr22152.c: Disable sinking.
>>
>> however, gcc.target/i386/pr22152.c FAILs now for 32-bit:
>>
>> FAIL: gcc.target/i386/pr22152.c scan-assembler-times movq[ \\\\t]+[^\\n]*%mm
>> 1
>
> I remember seeing this and was not able to make sense of the testcase
> which was added to fix some backend issue. Disabling sinking doesn't
> work (IIRC) as it is required to generate the original code as well.
>
> Uros added the testcase in 2008 -- I think if we want to have a testcase
> for the original issue we need a different one. Or simply remove
> the testcase.
No, there is something going on in the testcase:
.L3:
movq (%ecx,%eax,8), %mm1
paddq (%ebx,%eax,8), %mm1
addl $1, %eax
movq %mm1, %mm0
cmpl %eax, %edx
jne .L3
The compiler should allocate %mm0 to movq and paddq to avoid %mm1 ->
%mm0 move. These are all movv1di patterns (they shouldn't interfere
with movdi), and it is not clear to me why RA allocates %mm1 instead
of %mm0.
Uros.
