Arguments to function calls marked "nocapture" can be marked as
non-escaping. However, nocapture is defined in terms of the lifetime
of the callee, and if the callee can directly or indirectly recurse to
the caller, the semantics of nocapture are invalid.
Therefore, we eagerly discover which SCC each function belongs to,
and later can check if callee and caller of a callsite belong to
the same SCC, in which case there could be recursion.
This means that we can't be so optimistic in
getModRefInfo(ImmutableCallsite) - previously we assumed all call
arguments never aliased with an escaping global. Now we need to check,
because a global could now be passed as an argument but still not
escape.
This also solves a related conformance problem: MemCpyOptimizer can
turn non-escaping stores of globals into calls to intrinsics like
llvm.memcpy/llvm/memset. This confuses GlobalsAA, which knows the
global can't escape and so returns NoModRef when queried, when
obviously a memcpy/memset call does indeed reference and modify its
arguments.
This fixes PR24800, PR24801, and PR24802.
llvm-svn: 248576
Summary:
This also adds the first set of tests for operand bundles.
The optimizer has not been audited to ensure that it does the right
thing with operand bundles.
Depends on D12456.
Reviewers: reames, chandlerc, majnemer, dexonsmith, kmod, JosephTremoulet, rnk, bogner
Subscribers: maksfb, llvm-commits
Differential Revision: http://reviews.llvm.org/D12457
llvm-svn: 248551
The doesn't seem to be a difference and ELFOSABI_NONE seems to be far more
common:
* Linux doesn't care when loading and puts ELFOSABI_NONE on core dumps.
* Gold and bfd ld produce files with ELFOSABI_NONE.
* Gold and bfd ld seems to ignore EI_OSABI other than for freebsd.
* Gas puts ELFOSABI_NONE in most .o files.
llvm-svn: 248534
These are necessary for implementing mem_fence for
OpenCL 2.0.
The VI assembler tests are disabled since it seems to be
using the wrong encoding or opcode.
llvm-svn: 248532
Summary:
This change teaches `CallInst`s and `InvokeInst`s to maintain a set of
operand bundles as part of its operands. `CallInst`s and `InvokeInst`s
with operand bundles co-allocate some space before their `Use` array to
hold meta information about which of its operands are part of an operand
bundle.
The strings corresponding to the bundle tags are interned into
`LLVMContextImpl::BundleTagCache`
This change does not include any parsing / bitcode support. That's the
next change.
Depends on D12455.
Reviewers: reames, chandlerc, majnemer, dexonsmith, kmod, JosephTremoulet, rnk, bogner
Subscribers: MatzeB, sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12456
llvm-svn: 248527
Currently, the availability of DSP instructions (ACLE 6.4.7) is handled in a
hand-rolled tricky condition block in tools/clang/lib/Basic/Targets.cpp, with
a FIXME: attached.
This patch changes the handling of +t2dsp to be in line with other
architecture extensions.
Following a revert of r248152 and new review comments, this patch also includes
renaming FeatureDSPThumb2 -> FeatureDSP, hasThumb2DSP() -> hasDSP(), etc.
The spelling of "t2dsp" is preserved, pending a further investigation of its
possible external usage.
Differential Revision: http://reviews.llvm.org/D12937
llvm-svn: 248519
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.
llvm-svn: 248478
Summary:
With this change, subclasses of `llvm::User` will be able to co-allocate
a variable number of bytes (called a "descriptor") with the `llvm::User`
instance. The co-allocated descriptor can later be accessed using
`llvm::User::getDescriptor`. This will be used in later changes to
implement operand bundles.
This change steals one bit from `NumUserOperands`, but given that it is
still 28 bits wide I don't think this will be a practical issue.
This change does not allow allocating hung off uses with descriptors.
This only for simplicity, not for any fundamental reason; and we can
easily add this functionality later if needed.
Reviewers: reames, chandlerc, dexonsmith, kmod, majnemer, pete, JosephTremoulet
Subscribers: pete, sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12455
llvm-svn: 248453
...because that's what the cost model was intended to do.
As discussed in D12882, this fix has a temporary unintended consequence for
SimplifyCFG: it causes us to not speculate an fdiv. However, two wrongs make
PR24818 right, and two wrongs make PR24343 act right even though it's really
still wrong.
I intend to correct SimplifyCFG and add to CodeGenPrepare to account for this
cost model change and preserve the righteousness for the bug report cases.
https://llvm.org/bugs/show_bug.cgi?id=24818https://llvm.org/bugs/show_bug.cgi?id=24343
Differential Revision: http://reviews.llvm.org/D12882
llvm-svn: 248439
Note: I'm am not trying to describe what "should be"; I'm only describing what is true today.
This came out of my recent question to llvm-dev titled: When can the dominator tree not contain a node for a basic block?
Differential Revision: http://reviews.llvm.org/D13078
llvm-svn: 248417
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.
llvm-svn: 248405
Summary:
It is fairly common to call SE->getConstant(Ty, 0) or
SE->getConstant(Ty, 1); this change makes such uses a little bit
briefer.
I've refactored the call sites I could find easily to use getZero /
getOne.
Reviewers: hfinkel, majnemer, reames
Subscribers: sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12947
llvm-svn: 248362
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).
llvm-svn: 248357
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
llvm-svn: 248291
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.
llvm-svn: 248195
Based on conversations with Justin and a few others, these constructors
are really useful to have in the executable so that you can call them
from the debugger. After some measurements, these *particular* calls
aren't so problematic as to make them a good tradeoff for always inline.
Please let me know if there are other functions really needed for
debugging. The always inline attribute is a hack that we should only
really employ when it doesn't hurt.
llvm-svn: 248188
The definition of the DivergenceAnalysis pass was in a CPP
file and wasn't accessible to users of the analysis to get it
through "getAnalysis<>()".
This patch extracts the definition into a separate header that
can be used by users of the analysis to fetch the results.
Patch by Volkan Keles (vkeles@apple.com)
llvm-svn: 248186
Currently, the availability of DSP instructions (ACLE 6.4.7) is handled in a
hand-rolled tricky condition block in tools/clang/lib/Basic/Targets.cpp, with
a FIXME: attached.
This patch changes the handling of +t2dsp to be in line with other
architecture extensions.
Following review comments, also updating the description of FeatureDSPThumb2
in ARM.td.
Differential Revision: http://reviews.llvm.org/D12937
llvm-svn: 248152
James Molloy