On 06/30/2017 03:03 AM, Richard Earnshaw (lists) wrote:
> On 19/06/17 14:46, Richard Earnshaw (lists) wrote:
>> Many parallel set insns are of the form of a single set that also sets
>> the condition code flags. In this case the cost of such an insn is
>> normally the cost of the part that doesn't
On 19/06/17 14:46, Richard Earnshaw (lists) wrote:
> Many parallel set insns are of the form of a single set that also sets
> the condition code flags. In this case the cost of such an insn is
> normally the cost of the part that doesn't set the flags, since updating
> the condition flags is simpl
On Mon, Jun 19, 2017 at 12:40:53PM -0500, Segher Boessenkool wrote:
> On Mon, Jun 19, 2017 at 05:01:10PM +0100, Richard Earnshaw (lists) wrote:
> > Yeah, and I'm not suggesting we change the logic there (sorry if the
> > description was misleading). Instead I'm proposing that we handle more
> > ca
On Mon, Jun 19, 2017 at 05:01:10PM +0100, Richard Earnshaw (lists) wrote:
> Yeah, and I'm not suggesting we change the logic there (sorry if the
> description was misleading). Instead I'm proposing that we handle more
> cases for parallels to not return zero.
Right. My test run is half way throu
On 19/06/17 16:09, Segher Boessenkool wrote:
> On Mon, Jun 19, 2017 at 03:45:23PM +0100, Richard Earnshaw (lists) wrote:
At present all such insns are treated as having unknown cost (ie 0) and
combine assumes that such insns are infinitely more expensive than any
other insn sequence
On Mon, Jun 19, 2017 at 03:45:23PM +0100, Richard Earnshaw (lists) wrote:
> >> At present all such insns are treated as having unknown cost (ie 0) and
> >> combine assumes that such insns are infinitely more expensive than any
> >> other insn sequence with a non-zero cost.
> >
> > That's not what
On Mon, Jun 19, 2017 at 03:28:20PM +0100, Richard Earnshaw (lists) wrote:
> > That's not what combine does: it optimistically assumes any combination
> > with unknown costs is an improvement.
>
> So try this testcase on ARM.
>
> unsigned long x, y, z;
> int b;
> void test()
> {
>b = __builtin
On 19/06/17 15:08, Segher Boessenkool wrote:
> Hi!
>
> On Mon, Jun 19, 2017 at 02:46:59PM +0100, Richard Earnshaw (lists) wrote:
>> Many parallel set insns are of the form of a single set that also sets
>> the condition code flags. In this case the cost of such an insn is
>> normally the cost of
On 19/06/17 15:08, Segher Boessenkool wrote:
> Hi!
>
> On Mon, Jun 19, 2017 at 02:46:59PM +0100, Richard Earnshaw (lists) wrote:
>> Many parallel set insns are of the form of a single set that also sets
>> the condition code flags. In this case the cost of such an insn is
>> normally the cost of
Hi!
On Mon, Jun 19, 2017 at 02:46:59PM +0100, Richard Earnshaw (lists) wrote:
> Many parallel set insns are of the form of a single set that also sets
> the condition code flags. In this case the cost of such an insn is
> normally the cost of the part that doesn't set the flags, since updating
>
Many parallel set insns are of the form of a single set that also sets
the condition code flags. In this case the cost of such an insn is
normally the cost of the part that doesn't set the flags, since updating
the condition flags is simply a side effect.
At present all such insns are treated as
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