http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html
Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".
ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.
Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.
Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow
for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
BasicBlock *BB = i.getCaseSuccessor();
ConstantInt *V = i.getCaseValue();
// Do something.
}
If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.
There are also related changes in llvm-clients: klee and clang.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152297 91177308-0d34-0410-b5e6-96231b3b80d8
Allow targets to provide their own schedulers (subclass of
ScheduleDAGInstrs) to the misched pass. Select schedulers using
-misched=...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152278 91177308-0d34-0410-b5e6-96231b3b80d8
ScheduleDAGInstrs will be the main interface for MI-level
schedulers. Make sure it's readable: one page of protected fields, one
page of public methids.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152258 91177308-0d34-0410-b5e6-96231b3b80d8
This one is particularly annoying because the hashing algorithm is
highly specialized, with a strange "equivalence" definition that subsets
the fields involved.
Still, this looks at the exact same set of data as the old code, but
without bitwise or-ing over parts of it and other mixing badness. No
functionality changed here. I've left a substantial fixme about the fact
that there is a cleaner and more principled way to do this, but it
requires making the equality definition actual stable for particular
types...
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the DebugLoc information can be maintained throughout by grabbing the DebugLoc
before the RemoveBranch and then passing the result to the InsertBranch.
Patch by Andrew Stanford-Jason!
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ScheduleDAG is responsible for the DAG: SUnits and SDeps. It provides target hooks for latency computation.
ScheduleDAGInstrs extends ScheduleDAG and defines the current scheduling region in terms of MachineInstr iterators. It has access to the target's scheduling itinerary data. ScheduleDAGInstrs provides the logic for building the ScheduleDAG for the sequence of MachineInstrs in the current region. Target's can implement highly custom schedulers by extending this class.
ScheduleDAGPostRATDList provides the driver and diagnostics for current postRA scheduling. It maintains a current Sequence of scheduled machine instructions and logic for splicing them into the block. During scheduling, it uses the ScheduleHazardRecognizer provided by the target.
Specific changes:
- Removed driver code from ScheduleDAG. clearDAG is the only interface needed.
- Added enterRegion/exitRegion hooks to ScheduleDAGInstrs to delimit the scope of each scheduling region and associated DAG. They should be used to setup and cleanup any region-specific state in addition to the DAG itself. This is necessary because we reuse the same ScheduleDAG object for the entire function. The target may extend these hooks to do things at regions boundaries, like bundle terminators. The hooks are called even if we decide not to schedule the region. So all instructions in a block are "covered" by these calls.
- Added ScheduleDAGInstrs::begin()/end() public API.
- Moved Sequence into the driver layer, which is specific to the scheduling algorithm.
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The first def of a virtual register cannot also read the register.
Assert on such bad machine code instead of trying to fix it.
TwoAddressInstructionPass should never create code like that.
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We are already setting <undef> flags, and that is good enough. The
<imp-def> operands don't mean anything any more.
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The inline table needs to be constructed ahead of time so that it doesn't try to
create new strings while we're emitting everything.
This reverts commit a8ff9bccb399183cdd5f1c3cec2bda763664b4b0.
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fixups that are being used to determine section offsets. Reduces
the total number of fixups by 50% for a non-trivial testcase.
Part of rdar://10413936
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Simply treat bundles as instructions. Spill code is inserted between
bundles, never inside a bundle. Rewrite all operands in a bundle at
once.
Don't attempt and memory operand folding inside bundles.
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This allows the function to be inlined, and makes it suitable for use in
getInstructionIndex().
Also provide a const version. C++ is great for touch typing practice.
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This function does more or less the same as
MI::readsWritesVirtualRegister(), but it supports bundles as well.
It also determines if any constraint requires reading and writing
operands to use the same register. Most clients want to know.
Use the more modern MO.readsReg() instead of trying to sort out undefs
and partial redefines. Stop supporting the extra full <imp-def> operand
as an alternative to <def,undef> sub-register defines.
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Extract a base class and provide four specific sub-classes for iterating
over const/non-const bundles/instructions.
This eliminates the mystery bool constructor argument.
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methods are no longer needed now that LinearScan has gone away.
(Contains tweaks trivialSpillEverywhere to enable the removal of getNewVRegs).
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To avoid problems with zero shifts when getting the bits that move between words
we use a trick: first shift the by amount-1, then do another shift by one. When
amount is 0 (and size 32) we first shift by 31, then by one, instead of by 32.
Also fix a latent bug that emitted the low and high words in the wrong order
when shifting right.
Fixes PR12113.
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When the GEP index is a vector of pointers, the code that calculated the size
of the element started from the vector type, and not the contained pointer type.
As a result, instead of looking at the data element pointed by the vector, this
code used the size of the vector. This works for 32bit members (on 32bit
systems), but not for other types. Added code to peel the vector type and
added a test.
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the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.
Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.
rdar://8979299
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After the SlotIndex slot names were updated, it is possible to apply
stricter checks to live intervals.
Also treat bundles as bags of operands when checking live intervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151531 91177308-0d34-0410-b5e6-96231b3b80d8
uses of the vreg, since the old kills may no longer be valid. This was causing
-verify-machineinstrs to complain about uses after kills, and could potentially
have been causing subtle register allocation issues, but I haven't come across a
test case yet.
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variable declaration as an argument because we want that address
anyhow for our debug information.
This seems to fix rdar://9965111, at least we have more debug
information than before and from reading the assembly it appears
to be the correct location.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151335 91177308-0d34-0410-b5e6-96231b3b80d8
Assuming that a single std::set node adds 3 control words, a bitvector
can store (3*8+4)*8=224 registers in the allocated memory of a single
element in the std::set (x86_64). Also we don't have to call malloc
for every register added.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151269 91177308-0d34-0410-b5e6-96231b3b80d8
Before register allocation, instructions can be moved across calls in
order to reduce register pressure. After register allocation, we don't
gain a lot by moving callee-saved defs across calls. In fact, since the
scheduler doesn't have a good idea how registers are used in the callee,
it can't really make good scheduling decisions.
This changes the schedule in two ways: 1. Latencies to call uses and
defs are no longer accounted for, causing some random shuffling around
calls. This isn't really a problem since those uses and defs are
inaccurate proxies for what happens inside the callee. They don't
represent registers used by the call instruction itself.
2. Instructions are no longer moved across calls. This didn't happen
very often, and the scheduling decision was made on dubious information
anyway.
As with any scheduling change, benchmark numbers shift around a bit,
but there is no positive or negative trend from this change.
This makes the post-ra scheduler 5% faster for ARM targets.
The secret motivation for this patch is the introduction of register
mask operands representing call clobbers. The most efficient way of
handling regmasks in ScheduleDAGInstrs is to model them as barriers for
physreg live ranges, but not for virtreg live ranges. That's fine
pre-ra, but post-ra it would have the same effect as this patch.
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Added array subscript to SparseSet for convenience.
Slight reorg to make it easier to manage the def/use sets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151228 91177308-0d34-0410-b5e6-96231b3b80d8
The standard function epilog includes a .size directive, but ppc64 uses
an alternate local symbol to tag the actual start of each function.
Until recently, binutils accepted the .size directive as:
.size test1, .Ltmp0-test1
however, using this directive with recent binutils will result in the error:
.size expression for XXX does not evaluate to a constant
so we must use the label which actually tags the start of the function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151200 91177308-0d34-0410-b5e6-96231b3b80d8
The vast majority of virtual register definitions don't need an entry
in the DAG builder's VRegDefs set.
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Affect on SD scheduling and postRA scheduling:
Printing the DAG will display the nodes in top-down topological order.
This matches the order within the MBB and makes my life much easier in general.
Affect on misched:
We don't need to track virtual register uses at all. This is awesome.
I also intend to rely on the SUnit ID as a topo-sort index. So if A < B then we cannot have an edge B -> A.
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This makes RAFast 4% faster, and it gets rid of the dodgy DenseMap
iteration.
This also revealed that RAFast would sometimes dereference DenseMap
iterators after erasing other elements from the map. That does seem to
work in the current DenseMap implementation, but SparseSet doesn't allow
it.
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bundles. This method takes a bundle start and an MI being bundled, and makes
the intervals for the MI's operands appear to start/end on the bundle start.
Also fixes some minor cosmetic issues (whitespace, naming convention) in the
HMEditor code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151099 91177308-0d34-0410-b5e6-96231b3b80d8
Passes after RegAlloc should be able to rely on MRI->getNumVirtRegs() == 0.
This makes sharing code for pre/postRA passes more robust.
Now, to check if a pass is running before the RA pipeline begins, use MRI->isSSA().
To check if a pass is running after the RA pipeline ends, use !MRI->getNumVirtRegs().
PEI resets virtual regs when it's done scavenging.
PTX will either have to provide its own PEI pass or assign physregs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151032 91177308-0d34-0410-b5e6-96231b3b80d8
ecx = mov eax
al = mov ch
The second copy is not a nop because the sub-indices of ecx,ch is not the
same of that of eax/al.
Re-enabled machine-cp.
PR11940
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MRI keeps track of which physregs have been used. Make sure it gets
updated with all the regmask-clobbered registers.
Delete the closePhysRegsUsed() function which isn't necessary.
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any changes.
Internally this adds a private inner class HMEditor, to LiveIntervals. HMEditor provides
an API for updating live intervals when code is moved or bundled.
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This caused miscompilations on out-of-tree targets, and possibly i386 as
well.
I'll find some other way of hoisting %rip-relative loads from loops
containing calls.
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Thanks to Anton, Duncan and Rafael for helping me track this down.
Pointy hat to Rafael for introducing the bug in the first place.
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The existing framework for postra scheduling is library local. We want to keep it that way. Soon we will have a more general MachineScheduler interface. At that time, various bits will be exposed to targets. In the meantime, the VLIWPacketizer wants to use ScheduleDAGInstrs directly, so it needs to wrapped in a PIMPL to avoid exposing it to the target interface.
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method. This allows the target lowering code to not have to deal with MDNodes.
Also, avoid leaking memory like a sieve by not creating a global variable for
the image info section, but just emitting the code directly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150624 91177308-0d34-0410-b5e6-96231b3b80d8
I'll put MachineLICM back before PEI. All my arm/x86 benchmarks look good, but buildbots don't like it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150568 91177308-0d34-0410-b5e6-96231b3b80d8
The llc command line options for enabling/disabling passes are local to CodeGen/Passes.cpp. This patch associates those options with standard pass IDs so they work regardless of how the target configures the passes.
A target has two ways of overriding standard passes:
1) Redefine the pass pipeline (override TargetPassConfig::add%Stage)
2) Replace or suppress individiual passes with TargetPassConfig::substitutePass.
In both cases, the command line options associated with the pass override the target default.
For example, say a target wants to disable machine instruction scheduling by default:
- The target calls disablePass(MachineSchedulerID) but otherwise does not override any TargetPassConfig methods.
- Without any llc options, no scheduler is run.
- With -enable-misched, the standard machine scheduler is run and honors the -misched=... flag to select the scheduler variant, which may be used for performance evaluation or testing.
Sorry overridePass is ugly. I haven't thought of a better way without replacing the cl::opt framework. I hope to do that one day...
I haven't figured out why CodeGen uses char& for pass IDs. AnalysisID is much easier to use and less bug prone. I'm using it wherever I can for internal implementation. Maybe later we can change the global pass ID definitions as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150563 91177308-0d34-0410-b5e6-96231b3b80d8
Pretend that regmask interference ends at the 'dead' slot, even when
there is other interference ending at the 'reg' slot of the same
instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150531 91177308-0d34-0410-b5e6-96231b3b80d8
Perform all comparisons at instruction granularity, and make sure
register masks on uses count in both gaps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150530 91177308-0d34-0410-b5e6-96231b3b80d8
Only accept register masks when looking for an 'overlapping' def. When
Overlap is not set, the function searches for a proper definition of
Reg.
This means MI->modifiesRegister() considers register masks, but
MI->definesRegister() doesn't.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150529 91177308-0d34-0410-b5e6-96231b3b80d8
When a physreg is live in to a basic block, look for any instruction in
the block that clobbers the physreg.
The instruction doesn't have to properly redefine the register, any
overlapping clobber is OK.
This slightly changes live ranges when compiling with register masks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150528 91177308-0d34-0410-b5e6-96231b3b80d8
The MachO back-end needs to emit the garbage collection flags specified in the
module flags. This is a WIP, so the front-end hasn't been modified to emit these
flags just yet. Documentation and front-end switching to occur soon.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150507 91177308-0d34-0410-b5e6-96231b3b80d8
that are greater than the vector element type. For example BUILD_VECTOR
of type <1 x i1> with a constant i8 operand.
This patch fixes the assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150477 91177308-0d34-0410-b5e6-96231b3b80d8
The scheduler will sometimes check the implicit-def list on instructions
to properly handle pre-colored DAG edges.
Also check any register mask operands for physreg clobbers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150428 91177308-0d34-0410-b5e6-96231b3b80d8
v8i8 -> v8i32 on AVX machines. The codegen often scalarizes ANY_EXTEND nodes.
The DAGCombiner has two optimizations that can mitigate the problem. First,
if all of the operands of a BUILD_VECTOR node are extracted from an ZEXT/ANYEXT
nodes, then it is possible to create a new simplified BUILD_VECTOR which uses
UNDEFS/ZERO values to eliminate the scalar ZEXT/ANYEXT nodes.
Second, another dag combine optimization lowers BUILD_VECTOR into a shuffle
vector instruction.
In the case of zext v8i8->v8i32 on AVX, a value in an XMM register is to be
shuffled into a wide YMM register.
This patch modifes the second optimization and allows the creation of
shuffle vectors even when the newly generated vector and the original vector
from which we extract the values are of different types.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150340 91177308-0d34-0410-b5e6-96231b3b80d8
In case the MachineScheduling pass I'm working on doesn't work well
for another target, they can completely override it. This also adds a
hook immediately after the RegAlloc pass to cleanup immediately after
vregs go away. We may want to fold it into the postRA hook later.
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When using register masks, registers like %rip are clobbered by the
register mask. LICM should still be able to hoist instructions reading
%rip from a loop containing calls.
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It can be necessary to detach a register mask pointer from its
MachineOperand. This method is convenient for checking clobbered
physregs on a detached bitmask pointer.
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This makes global live range splitting behave identically with and
without register mask operands.
This is not necessarily the best way of using register masks for live
range splitting. It would be more efficient to first split global live
ranges around calls (i.e., register masks), and reserve the fine grained
per-physreg interference guidance for global live ranges that do not
cross calls.
For now the goal is to produce identical assembly when enabling register
masks.
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Make them accessible through MCInstrInfo. They are only used for debugging purposes so this doesn't
have an impact on performance. X86MCTargetDesc.o goes from 630K to 461K on x86_64.
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Creates a configurable regalloc pipeline.
Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.
When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.
CodeGen transformation passes are never "required" as an analysis
ProcessImplicitDefs does not require LiveVariables.
We have a plan to massively simplify some of the early passes within the regalloc superpass.
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