llvm-project

Commit Graph

Author	SHA1	Message	Date
Matthias Braun	b4f74224ff	AArch64: Fix cmpxchg O0 expansion - Rewrite livein calculation to use the computeLiveIns() helper function. This is slightly less efficient but easier to reason about and doesn't unnecessarily add pristine and reserved registers[1] - Zero the status register at the beginning of the loop to make sure it has a defined value. - Remove kill flags of values that need to stay alive throughout the loop. [1] An upcoming commit of mine will tighten the MachineVerifier to catch these. llvm-svn: 304048	2017-05-26 23:48:59 +00:00
Tim Northover	1021d89398	AArch64: properly calculate cmpxchg status in FastISel. We were relying on the misleadingly-names $status result to actually be the status. Actually it's just a scratch register that may or may not be valid (and is the inverse of the real ststus anyway). Success can be determined by comparing the value loaded against the one we wanted to see for "cmpxchg strong" loops like this. Should fix PR28819. llvm-svn: 277513	2016-08-02 20:22:36 +00:00
Ahmed Bougacha	a0cdd79070	[AArch64][FastISel] Select -O0 legal cmpxchg. At -O0, cmpxchg survives AtomicExpand: it's mostly straightforward to select it in fast-isel, and let the pseudo be expanded later. extractvalues on the result are the tricky part: the generic logic only works for legal types (and it would be painful to make it support illegal types), so we can only support i32/i64 cmpxchg. llvm-svn: 276183	2016-07-20 21:12:32 +00:00

Author

SHA1

Message

Date

Matthias Braun

b4f74224ff

AArch64: Fix cmpxchg O0 expansion

- Rewrite livein calculation to use the computeLiveIns() helper
  function. This is slightly less efficient but easier to reason about
  and doesn't unnecessarily add pristine and reserved registers[1]
- Zero the status register at the beginning of the loop to make sure it
  has a defined value.
- Remove kill flags of values that need to stay alive throughout the loop.

[1] An upcoming commit of mine will tighten the MachineVerifier to catch
    these.

llvm-svn: 304048

2017-05-26 23:48:59 +00:00

Tim Northover

1021d89398

AArch64: properly calculate cmpxchg status in FastISel.

We were relying on the misleadingly-names $status result to actually be the
status. Actually it's just a scratch register that may or may not be valid (and
is the inverse of the real ststus anyway). Success can be determined by
comparing the value loaded against the one we wanted to see for "cmpxchg
strong" loops like this.

Should fix PR28819.

llvm-svn: 277513

2016-08-02 20:22:36 +00:00

Ahmed Bougacha

a0cdd79070

[AArch64][FastISel] Select -O0 legal cmpxchg.

At -O0, cmpxchg survives AtomicExpand: it's mostly straightforward
to select it in fast-isel, and let the pseudo be expanded later.

extractvalues on the result are the tricky part: the generic logic
only works for legal types (and it would be painful to make it
support illegal types), so we can only support i32/i64 cmpxchg.

llvm-svn: 276183

2016-07-20 21:12:32 +00:00

3 Commits