3 Commits

Author SHA1 Message Date
Sam Parker
dc1f81fb55 [ARM] Allow unrolling of multi-block loops.
Before, loop unrolling was only enabled for loops with a single
block. This restriction has been removed and replaced by:
- allow a maximum of two exiting blocks,
- a four basic block limit for cores with a branch predictor.

Differential Revision: https://reviews.llvm.org/D38952


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316313 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-23 08:05:14 +00:00
Sam Parker
f281371190 [ARM] Improve loop unrolling for Cortex-M
- Set the default runtime unroll count to 4 and use the newly added
  UnrollRemainder option.
- Create loop cost and force unroll for a cost less than 12.
- Disable unrolling on Thumb1 only targets.

Differential Revision: https://reviews.llvm.org/D36134


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310997 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-16 07:42:44 +00:00
Sam Parker
e46d723b12 [ARM] Enable partial and runtime unrolling
Enable runtime and partial loop unrolling of simple loops without
calls on M-class cores. The thresholds are calculated based on
whether the target is Thumb or Thumb-2.

Differential Revision: https://reviews.llvm.org/D34619


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308956 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-25 08:51:30 +00:00