Hi all,
On Thu, Jul 09, 2020 at 10:29:44AM +0200, Jakub Jelinek via Gcc-patches wrote:
> On Thu, Jul 09, 2020 at 09:17:46AM +0100, Richard Sandiford wrote:
> > If target-independent code is going to optimise for “no subreg operand”
> > targets like nvptx, I think it needs to know that the target w
"Roger Sayle" writes:
> Hi Richard,
>
>> On Thu, Jul 09, 2020 at 09:17:46AM +0100, Richard Sandiford wrote:
>>> > + res = force_reg (mode, res);
>>>
>>> In general, this can be dangerous performance-wise on targets where
>>> subregs are free. If the move survives to the register allocator
Hi Richard,
> On Thu, Jul 09, 2020 at 09:17:46AM +0100, Richard Sandiford wrote:
>> > +res = force_reg (mode, res);
>>
>> In general, this can be dangerous performance-wise on targets where
>> subregs are free. If the move survives to the register allocators,
>> it increases the risk
Jakub Jelinek writes:
> On Thu, Jul 09, 2020 at 09:17:46AM +0100, Richard Sandiford wrote:
>> > --- a/gcc/internal-fn.c
>> > +++ b/gcc/internal-fn.c
>> > @@ -1627,6 +1627,9 @@ expand_mul_overflow (location_t loc, tree lhs, tree
>> > arg0, tree arg1,
>> > profile_pr
On Thu, Jul 09, 2020 at 09:17:46AM +0100, Richard Sandiford wrote:
> > --- a/gcc/internal-fn.c
> > +++ b/gcc/internal-fn.c
> > @@ -1627,6 +1627,9 @@ expand_mul_overflow (location_t loc, tree lhs, tree
> > arg0, tree arg1,
> > profile_probability::very_likely ());
>
"Roger Sayle" writes:
> This patch improves the RTL that the middle-end generates for testing
> signed overflow following a widening multiplication. During this
> expansion the middle-end generates a truncation which can get used
> multiple times. Placing this intermediate value in a pseudo regi
