Before rewriting uses of one value in A to register B, check that there
are no tied uses. That would require multiple A values to be rewritten.
This bug can't bite in the current version of the code for a fairly
subtle reason: A tied use would have caused 2-addr to insert a copy
before the use. If the copy has been coalesced, it will be found by the
same loop changed by this patch, and the optimization is aborted.
This was exposed by 400.perlbench and lua after applying a patch that
deletes joined copies aggressively.
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There is no reason to defer the collection of virtual registers whose
register class may be replaced with a larger class.
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Remaining virtreg->physreg copies were rematerialized during
updateRegDefsUses(), but we already do the same thing in joinCopy() when
visiting the physreg copy instruction.
Eliminate the preserveSrcInt argument to reMaterializeTrivialDef(). It
is now always true.
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Dead copies cause problems because they are trivial to coalesce, but
removing them gived the live range a dangling end point. This patch
enables full dead code elimination which trims live ranges to their uses
so end points don't dangle.
DCE may erase multiple instructions. Put the pointers in an ErasedInstrs
set so we never risk visiting erased instructions in the work list.
There isn't supposed to be any dead copies entering RegisterCoalescer,
but they do slip by as evidenced by test/CodeGen/X86/coalescer-dce.ll.
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getUDivExpr attempts to simplify by checking for overflow.
isLoopEntryGuardedByCond then evaluates the loop predicate which
may lead to the same getUDivExpr causing endless recursion.
Fixes PR12868: clang 3.2 segmentation fault.
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Use a dedicated MachO load command to annotate data-in-code regions.
This is the same format the linker produces for final executable images,
allowing consistency of representation and use of introspection tools
for both object and executable files.
Data-in-code regions are annotated via ".data_region"/".end_data_region"
directive pairs, with an optional region type.
data_region_directive := ".data_region" { region_type }
region_type := "jt8" | "jt16" | "jt32" | "jta32"
end_data_region_directive := ".end_data_region"
The previous handling of ARM-style "$d.*" labels was broken and has
been removed. Specifically, it didn't handle ARM vs. Thumb mode when
marking the end of the section.
rdar://11459456
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It is no longer necessary to separate VirtCopies, PhysCopies, and
ImpDefCopies. Implicitly defined copies are extremely rare after we
added the ProcessImplicitDefs pass, and physical register copies are not
joined any longer.
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This has been disabled for a while, and it is not a feature we want to
support. Copies between physical and virtual registers are eliminated by
good hinting support in the register allocator. Joining virtual and
physical registers is really a form of register allocation, and the
coalescer is not properly equipped to do that. In particular, it cannot
backtrack coalescing decisions, and sometimes that would cause it to
create programs that were impossible to register allocate, by exhausting
a small register class.
It was also very difficult to keep track of the live ranges of aliasing
registers when extending the live range of a physreg. By disabling
physreg joining, we can let fixed physreg live ranges remain constant
throughout the register allocator super-pass.
One type of physreg joining remains: A virtual register that has a
single value which is a copy of a reserved register can be merged into
the reserved physreg. This always lowers register pressure, and since we
don't compute live ranges for reserved registers, there are no problems
with aliases.
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SelectionDAGBuilder::Clusterify : main functinality was replaced with CRSBuilder::optimize, so big part of Clusterify's code was reduced.
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non-profitable commute using outdated info. The test case would still fail
because of poor pre-RA schedule. That will be fixed by MI scheduler.
rdar://11472010
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the 0b10 mask encoding bits. Make MSR APSR writes without a _<bits> qualifier
an alias for MSR APSR_nzcvq even though ARM as deprecated it use. Also add
support for suffixes (_nzcvq, _g, _nzcvqg) for APSR versions. Some FIXMEs in
the code for better error checking when versions shouldn't be used.
rdar://11457025
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Introduce the basic strategy for register pressure scheduling.
1) Respect target limits at all times.
2) Indentify critical register classes (pressure sets).
Track pressure within the scheduled region.
Avoid increasing scheduled pressure for critical registers.
3) Avoid exceeding the max pressure of the region prior to scheduling.
Added logic for picking between the top and bottom ready Q's based on
regpressure heuristics.
Status: functional but needs to be asjusted to achieve good results.
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RegisterCoalescer set <undef> flags on all operands of copy instructions
that are scheduled to be removed. This is so they won't affect
shrinkToUses() by introducing false register reads.
Make sure those <undef> flags are never cleared, or shrinkToUses() could
cause live intervals to end at instructions about to be deleted.
This would be a lot simpler if RegisterCoalescer could just erase joined
copies immediately instead of keeping all the to-be-deleted instructions
around.
This fixes PR12862. Unfortunately, bugpoint can't create a sane test
case for this. Like many other coalescer problems, this failure depends
of a very fragile series of events.
<rdar://problem/11474428>
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separate side table, using the handy SequenceToOffsetTable class. This encodes all
these weird things into another 256 bytes, allowing all intrinsics to be encoded this way.
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are only rejected because they can't be encoded into a 32-bit unit, not because
they contain an unencodable feature.
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llc to recognize MIPS16 as a MIPS ASE extension. -mips16 will mean the
mips16 ASE for mips32 by default.
As part of fixing of adding this we discovered some small changes that
need to be made to MipsInstrInfo::storeRegToStackSLot and
MipsInstrInfo::loadRegFromStackSlot. We were using some "==" equality tests
where in fact we should have been using Mips::<regclas>.hasSubClassEQ instead,
per suggestion of Jakob Stoklund Olesen.
Patch by Reed Kotler.
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When widening an existing <def,reads-undef> operand to a super-register,
it may be necessary to clear the <undef> flag because the wider register
is now read-modify-write through the instruction.
Conversely, it may be necessary to add an <undef> flag when the
coalescer turns a full-register def into a sub-register def, but the
larger register wasn't live before the instruction.
This happens in test/CodeGen/ARM/coalesce-subregs.ll, but the test
is too small for the <undef> flags to affect the generated code.
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It's more flexible for MCJIT tasks, in addition it's provides a invalidation instruction cache for code sections which will be used before JIT code will be executed.
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generated code (for Intrinsic::getType) into a table. This handles common cases right now,
but I plan to extend it to handle all cases and merge in type verification logic as well
in follow-on patches.
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It is now possible to coalesce weird skewed sub-register copies by
picking a super-register class larger than both original registers. The
included test case produces code like this:
vld2.32 {d16, d17, d18, d19}, [r0]!
vst2.32 {d18, d19, d20, d21}, [r0]
We still perform interference checking as if it were a normal full copy
join, so this is still quite conservative. In particular, the f1 and f2
functions in the included test case still have remaining copies because
of false interference.
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It is possible to coalesce two overlapping registers to a common
super-register that it larger than both of the original registers.
The important difference is that it may be necessary to rewrite DstReg
operands as well as SrcReg operands because the sub-register index has
changed.
This behavior is still disabled by CoalescerPair.
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Now both SrcReg and DstReg can be sub-registers of the final coalesced
register.
CoalescerPair::setRegisters still rejects such copies because
RegisterCoalescer doesn't yet handle them.
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This feature avoids creating edges in the scheduler's dependence graph
for non-aliasing memory operations according to whichever alias
analysis is available. It has been fully tested in Hexagon. Before
making this default, it needs to be extended to handle multiple
MachineMemOperands, compile time needs more evaluation, and
benchmarking on X86 and ARM is needed.
Patch by Sergei Larin!
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Add the MCRegisterInfo to the factories and constructors.
Patch by Tom Stellard <Tom.Stellard@amd.com>.
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The purpose of this option is to silence error messages issued by machine
verifier passes and enable them to run to the end. If this option is not
provided, -verify-machineinstrs complains when it discovers there is a
non-terminator instruction (an instruction that is in a delay slot) after the
first terminator in a basic block.
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RAFast must add an <imp-def> operand when it is rewriting a sub-register
def that isn't a read-modify-write.
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so that it can be reused in MemCpyOptimizer. This analysis is needed to remove
an unnecessary memcpy when returning a struct into a local variable.
rdar://11341081
PR12686
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Ordinary patch for PR1255.
Added new case-ranges orientated methods for adding/removing cases in SwitchInst. After this patch cases will internally representated as ConstantArray-s instead of ConstantInt, externally cases wrapped within the ConstantRangesSet object.
Old methods of SwitchInst are also works well, but marked as deprecated. So on this stage we have no side effects except that I added support for case ranges in BitcodeReader/Writer, of course test for Bitcode is also added. Old "switch" format is also supported.
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the ones that get or set the frame index for the $gp save slot.
Remove the piece of code in MipsFunctionInfo::getGlobalBaseReg() which returns
GP. This function should always return a virtual register.
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- Stop creating stack frame objects needed for saving $gp.
- Insert a node that copies the global pointer register to register $gp
before the call node. This will ensure $gp is valid at the entry of the
called function.
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- Stop emitting instructions needed to initialize the global pointer register.
- Stop emitting .cprestore directive.
- Do not take into account the $gp save slot when computing stack size.
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- Remove code which lowers pseudo SETGP01.
- Fix LowerSETGP01. The first two of the three instructions that are emitted to
initialize the global pointer register now use register $2.
- Stop emitting .cpload directive.
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Empty live ranges represent undef and still get allocated, but they
won't appear in LiveIntervalUnions.
Patch by Patrik Hägglund!
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pointer register.
This is the first of the series of patches which clean up the way global pointer
register is used. The patches will make the following improvements:
- Make $gp an allocatable temporary register rather than reserving it.
- Use a virtual register as the global pointer register and let the register
allocator decide which register to assign to it or whether spill/reloads are
needed.
- Make sure $gp is valid at the entry of a called function, which is necessary
for functions using lazy binding.
- Remove the need for emitting .cprestore and .cpload directives.
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This fixes a TODO from 2007 :) Previously, LLVM would emit the wrong
code here (see the update to test/CodeGen/X86/tls-pie.ll).
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This patch will optimize the following cases:
sub r1, r3 | sub r1, imm
cmp r3, r1 or cmp r1, r3 | cmp r1, imm
bge L1
TO
subs r1, r3
bge L1 or ble L1
If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.
rdar: 10734411
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add an additional parameter to InstCombiner::EmitGEPOffset() to force it to *not* emit operations with NUW flag
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Prioritize the instruction that comes closest to keeping pressure
under the target's limit. Then prioritize instructions that avoid
increasing the max pressure in the scheduled region. The max pressure
heuristic is a tad aggressive. Later I'll fix it to consider the
unscheduled pressure as well.
WIP: This is mostly functional but untested and not likely to do much good yet.
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Added getMaxExcessUpward/DownwardPressure. They somewhat abuse the
tracker by speculatively handling an instruction out of order. But it
is convenient for now. In the future, we will cache each instruction's
pressure contribution to make this efficient.
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This patch will optimize the following cases:
sub r1, r3 | sub r1, imm
cmp r3, r1 or cmp r1, r3 | cmp r1, imm
bge L1
TO
subs r1, r3
bge L1 or ble L1
If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.
rdar: 10734411
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156550 91177308-0d34-0410-b5e6-96231b3b80d8
