[Bug target/65225] New: [AArch64] Various aarch64_rtx_costs improvements

[Bug target/65225] New: [AArch64] Various aarch64_rtx_costs improvements

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65225

            Bug ID: 65225
           Summary: [AArch64] Various aarch64_rtx_costs improvements
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ktkachov at gcc dot gnu.org
            Target: aarch64*

The aarch64 rtx costs walker could be improved. Some particular areas:

- In the MINUS case, the cost of new_op1 is not included at all
- In the PLUS and MINUS case, extends and extended shifts are costed as
alu_arith rather than extend_arith
- In the PLUS and MINUS case if there is a ASHIFT or MULT after an
extend/extended shift, the cost calculated in rtx_mult_cost is as if it was a
plain PLUS/MINUS. If the multiply is by a power of 2, it calculates the cost as
a arith_shift rather than extend_arith. If it was ASHIFT the cost is wrong as
it expects a MULT rather than ASHIFT, so shift immediates which happen to be a
power of 2 get a different cost.
- In the ASHIFT case, if there is an extend the cost of extend should be used
rather than a shift.
ASHIFT 1 should use alu cost rather than shift cost (we emit an add if shift
cost is higher than alu cost)
- In the ASHIFRT/LSHIFTRT case the extend logic is missing.
- In the ABS case for integer, speed cost should be 2 ALU instructions rather
than 4.
- In the and-immediate case look into handling ZERO_EXTRACT.
- The NOT case misses logic for shifts (despite the comment, calculating shift
cost separately is not correct) - this can be costed as ORN with zero similar
to the way NEG works.

[Bug target/65225] [AArch64] Various aarch64_rtx_costs improvements

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65225

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |6.0

[Bug target/65225] [AArch64] Various aarch64_rtx_costs improvements

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65225

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-05-15
                 CC|                            |ramana at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |ktkachov at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Presumably yours ?

[Bug target/65225] [AArch64] Various aarch64_rtx_costs improvements

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65225

--- Comment #2 from ktkachov at gcc dot gnu.org ---
(In reply to Ramana Radhakrishnan from comment #1)
> Presumably yours ?

Yes, and I think it's fixed. At least all the important aarch64 patches are in
with.
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg00013.html is still waiting
though

[Bug target/65225] [AArch64] Various aarch64_rtx_costs improvements

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65225

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from ktkachov at gcc dot gnu.org ---
The aarch64 costs issue that I could find have been fixed on trunk for GCC 6