[PATCH, ARM] Initial pipeline description for Cortex-A7

["Greta Yorsh" <greta dot yorsh at arm dot com>]

Currently, GCC uses generic ARMv7-A tuning for Cortex-A7.
This patch adds an initial pipeline description for Cortex-A7. Details:
* integer/vfp is based on the pipeline description for Cortex-A5,
* models dual issue in limited circumstances using simple_alu_imm and
simple_alu_shift type attribute (introduced by a previous patch),
* basic neon timings.

No regression on qemu for arm-none-eabi target with cpu cortex-a7.

Bootstrap successful on Cortex-A15 (gcc configured with cpu cortex-a7).

Performance evaluation on Cortex-A7 hardware:

Coremark: 
* No change compared to generic tuning even though the generated assembly is
significantly different due to instruction scheduling. 
* Improvement compared to tuning for Cortex-A5: 4% improvement in arm mode
and 9% improvement in thumb mode.
CINT2000:
* compared to generic tuning, overall improvement of 1.9%.
* compared to tuning for Cortex-A5, overall improvement of 1.5%.
* in both cases, all benchmarks improved except 254.gap.
CFP2000:
* compared to generic tuning (which doesn't do much for FP), overall
improvement of 5.5%, all benchmarks improved.
* compared to Cortex-A5 tuning (as pipeline descriptions are nearly
identical) overall no change, but individual benchmarks mixed results.

Ok for trunk?

Thanks,
Greta

gcc/ChangeLog

2012-12-20  Greta Yorsh  <Greta.Yorsh@arm.com>

        * config/arm/cortex-a7.md: New file.
        * config/arm/arm.md: Include cortex-a7.md.
        (generic_sched): Don't use generic scheduler for Cortex-A7.
        (generic_vfp): Likewise.
        * config/arm/t-arm (arm_cpu_table): Likewise.
        * config/arm/arm.c: (TARGET_SCHED_REORDER): Use arm_sched_reorder.
        (arm_sched_reorder): New function.
        (cortexa7_older_only,cortexa7_younger): Likewise.

Attachment: cortex-a7-pipe.v3.patch.txt
Description: Text document