If a virtual register is copied and another copy was already
seen, replace with the previous copy. This only handles the
simplest cases for now.
This pattern shows up from various operand restrictions
AMDGPU has which require inserting copies depending
on the register class of the operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248611 91177308-0d34-0410-b5e6-96231b3b80d8
Allow a target to do something other than search for copies
that will avoid cross register bank copies.
Implement for SI by only rewriting the most basic copies,
so it should look through anything like a subregister extract.
I'm not entirely satisified with this because it seems like
eliminating a reg_sequence that isn't fully used should work
generically for all targets without them having to override
something. However, it seems to be tricky to have a simple
implementation of this without rewriting to invalid kinds
of subregister copies on some targets.
I'm not sure if there is currently a generic way to easily check
if a subregister index would be valid for the current use.
The current set of TargetRegisterInfo::get*Class functions don't
quite behave like I would expect (e.g. getSubClassWithSubReg
returns the maximal register class rather than the minimal), so
I'm not sure how to make the generic test keep searching if
SrcRC:SrcSubReg is a valid replacement for DefRC:DefSubReg. Making
the default implementation to check for simple copies breaks
a variety of ARM and x86 tests by producing illegal subregister uses.
The ARM tests are not actually changed since it should still be using
the same sharesSameRegisterFile implementation, this just relaxes
them to not check for specific registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248478 91177308-0d34-0410-b5e6-96231b3b80d8
If the stores are storing values from loads which partially
alias the stores, we could end up placing the merged loads
and stores on the same chain which has the potential to break.
Each store may have a different chain dependency on only some
of the original loads. Create a new TokenFactor to capture all
of the required dependencies of the stores rather than assuming
all stores can use the same chain.
The testcase is a situation where this happens, although
it does not have an observable change from this. The DAG nodes
just happened to not be reordered before despite this missing
chain dependency.
This is based on an off-list report for an out of tree target
which regressed due to r246307 and I haven't managed to find a case
where the nodes do end up reordered with an in tree target.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248468 91177308-0d34-0410-b5e6-96231b3b80d8
Add two new ways of accessing the unsafe stack pointer:
* At a fixed offset from the thread TLS base. This is very similar to
StackProtector cookies, but we plan to extend it to other backends
(ARM in particular) soon. Bionic-side implementation here:
https://android-review.googlesource.com/170988.
* Via a function call, as a fallback for platforms that provide
neither a fixed TLS slot, nor a reasonable TLS implementation (i.e.
not emutls).
This is a re-commit of a change in r248357 that was reverted in
r248358.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248405 91177308-0d34-0410-b5e6-96231b3b80d8
Add two new ways of accessing the unsafe stack pointer:
* At a fixed offset from the thread TLS base. This is very similar to
StackProtector cookies, but we plan to extend it to other backends
(ARM in particular) soon. Bionic-side implementation here:
https://android-review.googlesource.com/170988.
* Via a function call, as a fallback for platforms that provide
neither a fixed TLS slot, nor a reasonable TLS implementation (i.e.
not emutls).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248357 91177308-0d34-0410-b5e6-96231b3b80d8
Fixed the issue that when there is an edge from the jump table to the default statement, we should check it directly instead of checking if the sibling of the jump table header is a successor of the jump table header, which may not be the default statment but a successor of it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248354 91177308-0d34-0410-b5e6-96231b3b80d8
We may have subregister defs which are unused but not discovered and
cleaned up prior to liveness analysis. This creates multiple connected
components in the resulting live range which are forbidden in the
MachineVerifier because they would unnecesarily constrain the register
allocator. Rewrite those dead definitions to define a newly created
virtual register.
Differential Revision: http://reviews.llvm.org/D13035
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248335 91177308-0d34-0410-b5e6-96231b3b80d8
This improves ConnectedVNInfoEqClasses::Distribute() to distribute the
segments and value numbers in the subranges instead of conservatively
clearing all subregister info.
No separate test here, just clearing the subrange instead of properly
distributing them would however break my upcoming fix regarding dead super
register definitions.
Differential Revision: http://reviews.llvm.org/D13075
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248334 91177308-0d34-0410-b5e6-96231b3b80d8
In the comparison failure block of a cmpxchg expansion, the initial
ldrex/ldxr will not be followed by a matching strex/stxr.
On ARM/AArch64, this unnecessarily ties up the execution monitor,
which might have a negative performance impact on some uarchs.
Instead, release the monitor in the failure block.
The clrex instruction was designed for this: use it.
Also see ARMARM v8-A B2.10.2:
"Exclusive access instructions and Shareable memory locations".
Differential Revision: http://reviews.llvm.org/D13033
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248291 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for combining patterns such as (FMUL(FADD(1.0, x), y)) and (FMUL(FSUB(x, 1.0), y)) to their FMA equivalents.
This is useful in particular for linear interpolation cases such as (FADD(FMUL(x, t), FMUL(y, FSUB(1.0, t))))
Differential Revision: http://reviews.llvm.org/D13003
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248210 91177308-0d34-0410-b5e6-96231b3b80d8
Because mod is always exact, this function should have never taken a rounding mode argument. The actual implementation still has issues, which I'll look at resolving in a subsequent patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248195 91177308-0d34-0410-b5e6-96231b3b80d8
If storing multiple FP constants, some subset of the stores
would be replaced with integers due to visit order, so
MergeConsecutiveStores would only partially merge
these.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248169 91177308-0d34-0410-b5e6-96231b3b80d8
In if-conversion, there is a utility function MergeBlocks() that is used to merge blocks. However, when new edges are built in this function the edge weight is either not provided or not updated properly, leading to a modified CFG with incorrect edge weights. This patch corrects this issue.
Differential Revision: http://reviews.llvm.org/D12513
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248030 91177308-0d34-0410-b5e6-96231b3b80d8
We shifted the MachineBasicBlocks to the end of the MachineFunction in
DFS order. This will not ensure that MachineBasicBlocks which fell
through to one another will remain contiguous. Instead, implement
a stable sort algorithm for iplist.
This partially reverts commit r214150.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247978 91177308-0d34-0410-b5e6-96231b3b80d8
- Strenghten the logic to be sure we hoist the restore point out of the current
loop. (The fixes a bug with infinite loop, added as part of the patch.)
- Walk over the exit blocks of the current loop to conver to the desired restore
point in one iteration of the update loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247958 91177308-0d34-0410-b5e6-96231b3b80d8
getLandingPadSuccessor assumes that each invoke can have at most one EH
pad successor, but WinEH invokes can have more than one. Two out of
three callers of getLandingPadSuccessor don't use the returned
landingpad, so we can make them use this simple predicate instead.
Eventually we'll have to circle back and fix SplitKit.cpp so that
register allocation works. Baby steps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247904 91177308-0d34-0410-b5e6-96231b3b80d8
