helper class.
The default constructor creates invalid (isValid() == false) instances
and may be used to communicate that a mapping was not found.
llvm-svn: 265699
A virtual register may have either a register bank or a register class.
This is represented by a PointerUnion between the related classes.
Typically, a virtual register went through the following states
regarding register class and register bank:
1. Creation: None is set. Virtual registers are fully generic.
2. Register bank assignment: Register bank is set. Virtual registers
live into a register bank, but we do not know the constraints they need
to fulfil.
3. Instruction selection: Register class is set. Virtual registers are
bound by encoding constraints.
To map these states to GlobalISel, the IRTranslator implements #1,
RegBankSelect #2, and Select #3.
llvm-svn: 265696
This patch add support for GCC attribute((ifunc("resolver"))) for
targets that use ELF as object file format. In general ifunc is a
special kind of function alias with type @gnu_indirect_function. Patch
for Clang http://reviews.llvm.org/D15524
Differential Revision: http://reviews.llvm.org/D15525
llvm-svn: 265667
The iterators of SmallPtrSet SpillsInSubTreeMap[Child].first may be
invalidated when SpillsInSubTreeMap grows. Rearrange the code to
ensure the grow of SpillsInSubTreeMap only happens before getting
the iterators of the SmallPtrSet.
llvm-svn: 265639
Clarify what this RemapFlag actually means.
- Change the flag name to match its intended behaviour.
- Clearly document that it's not supposed to affect globals.
- Add a host of FIXMEs to indicate how to fix the behaviour to match
the intent of the flag.
RF_IgnoreMissingLocals should only affect the behaviour of
RemapInstruction for function-local operands; namely, for operands of
type Argument, Instruction, and BasicBlock. Currently, it is *only*
passed into RemapInstruction calls (and the transitive MapValue calls
that it makes).
When I split Metadata from Value I didn't understand the flag, and I
used it in a bunch of places for "global" metadata.
This commit doesn't have any functionality change, but prepares to
cleanup MapMetadata and MapValue.
llvm-svn: 265628
getInstrMapping.
This implementation requires that the target implemented
getRegBankFromRegClass.
Indeed, the implementation uses the register classes for the encoding
constraints for the instructions to deduce the mapping of a value.
llvm-svn: 265624
This will be used by the register bank select pass to assign register banks
for generic virtual registers.
This was originally committed as r265573 but broke at least one windows bot.
The problem with the windows bot was that it was using a copy constructor for
the InstructionMappings class and could not synthesize it. Actually, the fact
that this class is not copy constructable is expected and the compiler should
use the move assignment constructor. Marking the problematic assignment
explicitly as using the move constructor has its own problems.
Indeed, with recent clang we get a warning that we may prevent the elision of
the copy by the compiler. A proper fix for both compilers would be to change the
API of getPossibleInstrMapping to take a InstructionMappings as input/output
parameter. This does not feel natural and since GISel is not used on windows
yet, I chose to workaround the problem by not compiling the problematic code on
windows.
llvm-svn: 265604
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.
The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).
This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.
As a follow-up I'll add:
bool operator<(AtomicOrdering, AtomicOrdering) = delete;
bool operator>(AtomicOrdering, AtomicOrdering) = delete;
bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.
Reviewers: jyknight, reames
Subscribers: jyknight, llvm-commits
Differential Revision: http://reviews.llvm.org/D18775
llvm-svn: 265602
instruction on a register bank. This will be used by the register bank select
pass to assign register banks for generic virtual registers." and the follow-on
commits while I find out a way to fix the win7 bot:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/19882
This reverts commit r265578, r265581, r265584, and r265585.
llvm-svn: 265587
helper class.
The default constructor creates invalid (isValid() == false) instances
and may be used to communicate that a mapping was not found.
llvm-svn: 265581
The method checks that the value is fully defined accross the different partial
mappings and that the partial mappings are compatible between each other.
llvm-svn: 265556
when DenseMap growed and moved memory. I verified it fixed the bootstrap
problem on x86_64-linux-gnu but I cannot verify whether it fixes
the bootstrap error on clang-ppc64be-linux. I will watch the build-bot
result closely.
Replace analyzeSiblingValues with new algorithm to fix its compile
time issue. The patch is to solve PR17409 and its duplicates.
analyzeSiblingValues is a N x N complexity algorithm where N is
the number of siblings generated by reg splitting. Although it
causes siginificant compile time issue when N is large, it is also
important for performance since it removes redundent spills and
enables rematerialization.
To solve the compile time issue, the patch removes analyzeSiblingValues
and replaces it with lower cost alternatives containing two parts. The
first part creates a new spill hoisting method in postOptimization of
register allocation. It does spill hoisting at once after all the spills
are generated instead of inside every instance of selectOrSplit. The
second part queries the define expr of the original register for
rematerializaiton and keep it always available during register allocation
even if it is already dead. It deletes those dead instructions only in
postOptimization. With the two parts in the patch, it can remove
analyzeSiblingValues without sacrificing performance.
Differential Revision: http://reviews.llvm.org/D15302
llvm-svn: 265547
While preserving the return value for @llvm.experimental.deoptimize at
the IR level is useful during mid-level optimization, doing so at the
machine instruction level requires generating some extra code and a
return that is non-ideal. This change has LLVM lower
```
%val = call @llvm.experimental.deoptimize
ret %val
```
to effectively
```
call @__llvm_deoptimize()
unreachable
```
instead.
llvm-svn: 265502
As part of the TRI argument of addRegBankCoverage we already have access to
the TargetRegisterClass through the ID of that register class.
Therefore, there is no point in needing a TargetRegisterClass instance,
the ID is enough to get to it.
llvm-svn: 265487
Bionic has a defined thread-local location for the stack protector
cookie. Emit a direct load instead of going through __stack_chk_guard.
llvm-svn: 265481
Change the default constructor to create invalid object.
The target will have to properly initialize the register banks before
using them.
llvm-svn: 265460
At IR level, the swifterror argument is an input argument with type
ErrorObject**. For targets that support swifterror, we want to optimize it
to behave as an inout value with type ErrorObject*; it will be passed in a
fixed physical register.
The main idea is to track the virtual registers for each swifterror value. We
define swifterror values as AllocaInsts with swifterror attribute or a function
argument with swifterror attribute.
In SelectionDAGISel.cpp, we set up swifterror values (SwiftErrorVals) before
handling the basic blocks.
When iterating over all basic blocks in RPO, before actually visiting the basic
block, we call mergeIncomingSwiftErrors to merge incoming swifterror values when
there are multiple predecessors or to simply propagate them. There, we create a
virtual register for each swifterror value in the entry block. For predecessors
that are not yet visited, we create virtual registers to hold the swifterror
values at the end of the predecessor. The assignments are saved in
SwiftErrorWorklist and will be materialized at the end of visiting the basic
block.
When visiting a load from a swifterror value, we copy from the current virtual
register assignment. When visiting a store to a swifterror value, we create a
virtual register to hold the swifterror value and update SwiftErrorMap to
track the current virtual register assignment.
Differential Revision: http://reviews.llvm.org/D18108
llvm-svn: 265433
Presently, CodeGenPrepare deletes all nearly empty (only phi and branch)
basic blocks. This pass can delete loop preheaders which frequently creates
critical edges. A preheader can be a convenient place to spill registers to
the stack. If the entrance to a loop body is a critical edge, then spills
may occur in the loop body rather than immediately before it. This patch
protects loop preheaders from deletion in CodeGenPrepare even if they are
nearly empty.
Since the patch alters the CFG, it affects a large number of test cases.
In most cases, the changes are merely cosmetic (basic blocks have different
names or instruction orders change slightly). I am somewhat concerned about
the test/CodeGen/Mips/brdelayslot.ll test case. If the loop preheader is not
deleted, then the MIPS backend does not take advantage of a branch delay
slot. Consequently, I would like some close review by a MIPS expert.
The patch also partially subsumes D16893 from George Burgess IV. George
correctly notes that CodeGenPrepare does not actually preserve the dominator
tree. I think the dominator tree was usually not valid when CodeGenPrepare
ran, but I am using LoopInfo to mark preheaders, so the dominator tree is
now always valid before CodeGenPrepare.
Author: Tom Jablin (tjablin)
Reviewers: hfinkel george.burgess.iv vkalintiris dsanders kbarton cycheng
http://reviews.llvm.org/D16984
llvm-svn: 265397
There is no problem with the code today, but the fix will avoid a crash
in test/CodeGen/AMDGPU/subreg-coalescer-undef-use.ll once the
DetectDeadLanes pass is added.
llvm-svn: 265351
I noticed that this isn't covered by our existing tests and spent some
time trying to come up with an example it actually hits. I tried hand
rolling something based on the explanation in the comment, but couldn't
get anything that didn't abort tail duplication earlier for one reason
or another.
Then, I tried cranking tail-dup-size cranked up so this would fire
more and ran a bootstrap of clang and the nightly test suite - those
don't hit this either.
This reverts r132816 and replaces it with an assert.
llvm-svn: 265347
That commit looks wonderful and awesome. Sadly, it greatly exacerbates
PR17409 and effectively regresses build time for a lot of (very large)
code when compiled with ASan or MSan.
We thought this could be fixed forward by landing D15302 which at last
fixes that PR, but some issues were discovered and it looks like that
got reverted, so reverting this as well temporarily. As soon as the fix
for PR17409 lands and sticks, we should re-land this patch as it won't
trigger more significant test cases hitting that bug.
Many thanks to Quentin and Wei here as they're doing all the awesome
hard work!!!
llvm-svn: 265331
