On Thu, Oct 15, 2015 at 3:50 PM, Christophe Lyon
<christophe.l...@linaro.org> wrote:
> On 9 October 2015 at 18:11, James Greenhalgh <james.greenha...@arm.com> wrote:
>> On Thu, Oct 08, 2015 at 01:29:34PM +0100, Richard Biener wrote:
>>> > Thanks again for the comments Richard!
>>> >
>>> > A new algorithmic optimisation:
>>> >
>>> > ((X inner_op C0) outer_op C1)
>>> > With X being a tree where value_range has reasoned certain bits to always
>>> > be
>>> > zero throughout its computed value range, we will call this the zero_mask,
>>> > and with inner_op = {|,^}, outer_op = {|,^} and inner_op != outer_op.
>>> > if (inner_op == '^') C0 &= ~C1;
>>> > if ((C0 & ~zero_mask) == 0) then emit (X outer_op (C0 outer_op C1)
>>> > if ((C1 & ~zero_mask) == 0) then emit (X inner_op (C0 outer_op C1)
>>> >
>>> > And extended '(X & C2) << C1 into (X << C1) & (C2 << C1)' and
>>> > '(X & C2) >> C1 into (X >> C1) & (C2 >> C1)' to also accept the bitwise or
>>> > and xor operators:
>>> > '(X {&,^,|} C2) << C1 into (X << C1) {&,^,|} (C2 << C1)' and
>>> > '(X {&,^,|} C2) >> C1 into (X >> C1) & (C2 >> C1)'.
>>> >
>>> > The second transformation enables more applications of the first. Also
>>> > some
>>> > targets may benefit from delaying shift operations. I am aware that such
>>> > an
>>> > optimization, in combination with one or more optimizations that cause the
>>> > reverse transformation, may lead to an infinite loop. Though such behavior
>>> > has not been detected during regression testing and bootstrapping on
>>> > aarch64.
>>> >
>>> > gcc/ChangeLog:
>>> >
>>> > 2015-10-05 Andre Vieira <andre.simoesdiasvie...@arm.com>
>>> >
>>> > * match.pd: Added a new pattern
>>> > ((X inner_op C0) outer_op C1)
>>> > and expanded existing one
>>> > (X {|,^,&} C0) {<<,>>} C1 -> (X {<<,>>} C1) {|,^,&} (C0 {<<,>>} C1)
>>> >
>>> > gcc/testsuite/ChangeLog:
>>> >
>>> > 2015-10-05 Andre Vieira <andre.simoesdiasvie...@arm.com>
>>> >
>>> > Hale Wang <hale.w...@arm.com>
>>> >
>>> > * gcc.dg/tree-ssa/forwprop-33.c: New test.
>>>
>>> Ok.
>>>
>>> Thanks,
>>> Richard.
>>>
>>
>> As Andre does not have commit rights, I've committed this on his behalf as
>> revision 228661. Please watch for any fallout over the weekend.
>>
>
> Since this commit I'm seeing:
> FAIL: gcc.target/arm/xor-and.c scan-assembler orr
> on most arm targets.
>
> See:
> http://people.linaro.org/~christophe.lyon/cross-validation/gcc/trunk/228661/report-build-info.html
>
> Since that's already a few days old, I suspect you are already aware of that?
Please file a bugreport.
Thanks,
Richard.
> Christophe.
>
>
>> Andre, please check your ChangeLog format in future. In the end I
>> committed this:
>>
>> gcc/ChangeLog
>>
>> 2015-10-09 Andre Vieira <andre.simoesdiasvie...@arm.com>
>>
>> * match.pd: ((X inner_op C0) outer_op C1) New pattern.
>> ((X & C2) << C1): Expand to...
>> (X {&,^,|} C2 << C1): ...This.
>> ((X & C2) >> C1): Expand to...
>> (X {&,^,|} C2 >> C1): ...This.
>>
>> gcc/testsuite/ChangeLog
>>
>> 2015-10-09 Andre Vieira <andre.simoesdiasvie...@arm.com>
>> Hale Wang <hale.w...@arm.com>
>>
>> * gcc.dg/tree-ssa/forwprop-33.c: New.
>>
>> Thanks,
>> James
>>
