Select instructions pick one of two virtual registers based on a
condition, like x86 cmov. On targets like ARM that support predication,
selects can sometimes be eliminated by predicating the instruction
defining one of the operands.
Teach PeepholeOptimizer to recognize select instructions, and ask the
target to optimize them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162059 91177308-0d34-0410-b5e6-96231b3b80d8
subtarget CPU descriptions and support new features of
MachineScheduler.
MachineModel has three categories of data:
1) Basic properties for coarse grained instruction cost model.
2) Scheduler Read/Write resources for simple per-opcode and operand cost model (TBD).
3) Instruction itineraties for detailed per-cycle reservation tables.
These will all live side-by-side. Any subtarget can use any
combination of them. Instruction itineraries will not change in the
near term. In the long run, I expect them to only be relevant for
in-order VLIW machines that have complex contraints and require a
precise scheduling/bundling model. Once itineraries are only actively
used by VLIW-ish targets, they could be replaced by something more
appropriate for those targets.
This tablegen backend rewrite sets things up for introducing
MachineModel type #2: per opcode/operand cost model.
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The TableGenBackend base class doesn't do much, and will be removed
completely soon.
Patch by Sean Silva!
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We cannot limit the concatenated instruction names to 64K. ARM is
already at 32K, and it is easy to imagine a target with more
instructions.
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Original commit message:
Use uint16_t to store InstrNameIndices in MCInstrInfo. Add asserts to protect all 16-bit string table offsets. Also make sure the string to offset table string is not larger than 65536 characters since larger string literals aren't portable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152296 91177308-0d34-0410-b5e6-96231b3b80d8
Original commit message:
Use uint16_t to store InstrNameIndices in MCInstrInfo. Add asserts to protect
all 16-bit string table offsets. Also make sure the string to offset table
string is not larger than 65536 characters since larger string literals aren't
portable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152233 91177308-0d34-0410-b5e6-96231b3b80d8
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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Many targets use pseudo instructions to help register allocation. Like
the COPY instruction, these pseudos can be expanded after register
allocation. The early expansion can make life easier for PEI and the
post-ra scheduler.
This patch adds a hook that is called for all remaining pseudo
instructions from the ExpandPostRAPseudos pass.
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No functionality change. The hook makes it explicit which patterns
require "special" handling. i.e. it self-documents tblgen
deficiencies. I plan to add verification in ExpandISelPseudos and
Thumb2SizeReduce to catch any missing hasPostISelHooks. Otherwise it's
too fragile.
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Modified ARMISelLowering::AdjustInstrPostInstrSelection to handle the
full gamut of CPSR defs/uses including instructins whose "optional"
cc_out operand is not really optional. This allowed removal of the
hasPostISelHook to simplify the .td files and make the implementation
more robust.
Fixes rdar://10137436: sqlite3 miscompile
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Add a instruction flag: hasPostISelHook which tells the pre-RA scheduler to
call a target hook to adjust the instruction. For ARM, this is used to
adjust instructions which may be setting the 's' flag. ADC, SBC, RSB, and RSC
instructions have implicit def of CPSR (required since it now uses CPSR physical
register dependency rather than "glue"). If the carry flag is used, then the
target hook will *fill in* the optional operand with CPSR. Otherwise, the hook
will remove the CPSR implicit def from the MachineInstr.
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MSVC decorates (and distinguishes) "const" in mangler. It brought linkage error between "extern const" declarations and definitions.
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- The actual values are from the MCOI::OperandType enum.
- Teach tblgen to read it from the instruction definition.
- This is a better implementation of the hacks in edis.
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Manage Inits in a FoldingSet. This provides several benefits:
- Memory for Inits is properly managed
- Duplicate Inits are folded into Flyweights, saving memory
- It enforces const-correctness, protecting against certain classes
of bugs
The above benefits allow Inits to be used in more contexts, which in
turn provides more dynamism to TableGen. This enhanced capability
will be used by the AVX code generator to a fold common patterns
together.
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itineraries.
- Refactor TargetSubtarget to be based on MCSubtargetInfo.
- Change tablegen generated subtarget info to initialize MCSubtargetInfo
and hide more details from targets.
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sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.
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Make the Elements vector private and expose an ArrayRef through
getOrder() instead. getOrder will eventually provide multiple
user-specified allocation orders.
Use the sorted member set for member and subclass tests. Clean up a lot
of ad hoc searches.
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and xor. The 32-bit move immediates can be hoisted out of loops by machine
LICM but the isel hacks were preventing them.
Instead, let peephole optimization pass recognize registers that are defined by
immediates and the ARM target hook will fold the immediates in.
Other changes include 1) do not fold and / xor into cmp to isel TST / TEQ
instructions if there are multiple uses. This happens when the 'and' is live
out, machine sink would have sinked the computation and that ends up pessimizing
code. The peephole pass would recognize situations where the 'and' can be
toggled to define CPSR and eliminate the comparison anyway.
2) Move peephole pass to after machine LICM, sink, and CSE to avoid blocking
important optimizations.
rdar://8663787, rdar://8241368
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need the Compare flag after all.
--- Reverse-merging r109901 into '.':
U include/llvm/Target/TargetInstrDesc.h
U include/llvm/Target/Target.td
U utils/TableGen/InstrInfoEmitter.cpp
U utils/TableGen/CodeGenInstruction.cpp
U utils/TableGen/CodeGenInstruction.h
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later to identify and possibly remove superfluous compare instructions -- those
that are testing for and setting a status flag that should already be set.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109901 91177308-0d34-0410-b5e6-96231b3b80d8
