Allows us to de-virtualize the function and provides access to it in
the instruction printer, which is useful for handling composite
physical registers (e.g., ARM register lists).
llvm-svn: 151815
This allows us to make TRC non-polymorphic and value-initializable, eliminating a huge static
initializer and a ton of cruft from the generated code.
Shrinks ARMBaseRegisterInfo.o by ~100k.
llvm-svn: 151806
The hook returns a bit-mask of call-preserved registers that will
eventually replace the current list of implicit defs on call
instructions. This will make it possible to support multiple calling
conventions without duplicating call instruction descriptors.
The call-preserved mask is slightly different from the list returned by
the getCalleeSavedRegs() hook, it includes all aliases that are
preserved by calls.
The hook takes a CallingConv::ID argument instead of a MachineFunction
pointer, so it can provide information about calls to extern functions,
and even indirect function calls.
TRI::getCalleeSavedRegs() returns information about the function
currently being compiled. TRI::getCallPreservedMask() returns
information about the functions it is calling.
llvm-svn: 148165
Use information computed while inferring new register classes to emit
accurate, table-driven implementations of getMatchingSuperRegClass().
Delete the old manual, error-prone implementations in the targets.
llvm-svn: 146873
This restores my karma after I added TRI::getSubClassWithSubReg().
Register constraints are applied 'backwards'. Starting from the
register class required by an instruction operand, the correct question
is: 'How can I constrain the super-register register class so all its
sub-registers satisfy the instruction constraint?' The
getMatchingSuperRegClass() hook answers that.
We never need to go 'forwards': Starting from a super-register register
class, what register class are the sub-registers in? The
getSubRegisterRegClass() hook did that.
llvm-svn: 141258
This function is used to constrain a register class to a sub-class that
supports the given sub-register index.
For example, getSubClassWithSubReg(GR32, sub_8bit) -> GR32_ABCD.
The function will be used to compute register classes when emitting
INSERT_SUBREG and EXTRACT_SUBREG nodes and for register class inflation
of sub-register operations.
The version provided by TableGen is usually adequate, but targets can
override.
llvm-svn: 141142
This uses less memory and it reduces the complexity of sub-class
operations:
- hasSubClassEq() and friends become O(1) instead of O(N).
- getCommonSubClass() becomes O(N) instead of O(N^2).
In the future, TableGen will infer register classes. This makes it
cheap to add them.
llvm-svn: 140898
This makes TargetRegisterClass slightly slower. Next step will be making contains faster.
Eventually TargetRegisterClass will be killed entirely.
llvm-svn: 135835
to MCRegisterInfo. Also initialize the mapping at construction time.
This patch eliminate TargetRegisterInfo from TargetAsmInfo. It's another step
towards fixing the layering violation.
llvm-svn: 135424
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.
llvm-svn: 134021
target machine from those that are only needed by codegen. The goal is to
sink the essential target description into MC layer so we can start building
MC based tools without needing to link in the entire codegen.
First step is to refactor TargetRegisterInfo. This patch added a base class
MCRegisterInfo which TargetRegisterInfo is derived from. Changed TableGen to
separate register description from the rest of the stuff.
llvm-svn: 133782
Targets that need to change the default allocation order should use the
AltOrders mechanism instead. See the X86 and ARM targets for examples.
The allocation_order_begin() and allocation_order_end() methods have been
replaced with getRawAllocationOrder(), and there is further support
functions in RegisterClassInfo.
It is no longer possible to insert arbitrary code into generated
register classes. This is a feature.
llvm-svn: 133332
Also switch the return type to ArrayRef<unsigned> which works out nicely
for ARM's implementation of this function because of the clever ArrayRef
constructors.
The name change indicates that the returned allocation order may contain
reserved registers as has been the case for a while.
llvm-svn: 133216
This virtual function will replace allocation_order_begin/end as the one
to override when implementing custom allocation orders. It is simpler to
have one function return an ArrayRef than having two virtual functions
computing different ends of the same array.
Use getRawAllocationOrder() in place of allocation_order_begin() where
it makes sense, but leave some clients that look like they really want
the filtered allocation orders from RegisterClassInfo.
llvm-svn: 133170
At the time I wrote this code (circa 2007), TargetRegisterInfo was using a std::set to perform these queries. Switching to the static hashtables was an obvious improvement, but in reality there's no reason to do anything other than scan.
With this change, total LLC time on a whole-program 403.gcc is reduced by approximately 1.5%, almost all of which comes from a 15% reduction in LiveVariables time. It also reduces the binary size of LLC by 86KB, thanks to eliminating a bunch of very large static tables.
llvm-svn: 133051
Make the hash tables as small as possible while ensuring that all
lookups can be done in less than 8 probes.
Cut the aliases hash table in half by only storing a < b pairs - it
is a symmetric relation.
Use larger multipliers on the initial hash function to ensure that it
properly covers the whole table, and to resolve some clustering in the
very regular ARM register bank.
This reduces the size of most of these tables by 4x - 8x. For instance,
the ARM tables shrink from 48 KB to 8 KB.
llvm-svn: 132888
Besides moving structural computations to CodeGenRegisters.cpp, this
also well-defines the order of these lists:
- Sub-register lists come from a pre-order traversal of the graph
defined by the SubRegs lists in the .td files.
- Super-register lists are topologically ordered so no register comes
before any of its sub-registers. When the sub-register graph is not a
tree, independent super-registers appear in numerical order.
- Lists of overlapping registers are ordered according to register
number.
This reverses the order of the super-regs lists, but nobody was
depending on that. The previous order of the overlaps lists was odd, and
it may have depended on the precise behavior of std::stable_sort.
The old computations are still there, but will be removed shortly.
llvm-svn: 132881
Some register classes are only used for instruction operand constraints.
They should never be used for virtual registers. Previously, those
register classes were given an empty allocation order, but now you can
say 'let isAllocatable=0' in the register class definition.
TableGen calculates if a register is part of any allocatable register
class, and makes that information available in TargetRegisterDesc::inAllocatableClass.
The goal here is to eliminate use cases for overriding allocation_order_*
methods.
llvm-svn: 132508
Add TargetRegisterInfo::hasSubClassEq and use it to check for compatible
register classes instead of trying to list all register classes in
X86's getLoadStoreRegOpcode.
llvm-svn: 132398
The hook will be used by the register allocator when recomputing register
classes after removing constraints.
Thumb1 code doesn't allow anything larger than tGPR, and x86 needs to ensure
that the spill size doesn't change.
llvm-svn: 130228
On the x86-64 and thumb2 targets, some registers are more expensive to encode
than others in the same register class.
Add a CostPerUse field to the TableGen register description, and make it
available from TRI->getCostPerUse. This represents the cost of a REX prefix or a
32-bit instruction encoding required by choosing a high register.
Teach the greedy register allocator to prefer cheap registers for busy live
ranges (as indicated by spill weight).
llvm-svn: 129864
Add a avoidWriteAfterWrite() target hook to identify register classes that
suffer from write-after-write hazards. For those register classes, try to avoid
writing the same register in two consecutive instructions.
This is currently disabled by default. We should not spill to avoid hazards!
The command line flag -avoid-waw-hazard can be used to enable waw avoidance.
llvm-svn: 129772
flexible.
If it returns a register class that's different from the input, then that's the
register class used for cross-register class copies.
If it returns a register class that's the same as the input, then no cross-
register class copies are needed (normal copies would do).
If it returns null, then it's not at all possible to copy registers of the
specified register class.
llvm-svn: 127368
Fix the TargetRegisterInfo::NoRegister places where someone preferred
typing 'TargetRegisterInfo::NoRegister' instead of typing '0'.
Note that TableGen is already emitting xx::NoRegister in xxGenRegisterNames.inc.
llvm-svn: 123140
The numbering plan is now:
0 NoRegister.
[1;2^30) Physical registers.
[2^30;2^31) Stack slots.
[2^31;2^32) Virtual registers. (With -1u and -2u used by DenseMapInfo.)
Each segment is filled from the left, so any mistaken interpretation should
quickly cause crashes.
FirstVirtualRegister has been removed. TargetRegisterInfo provides predicates
conversion functions that should be used instead of interpreting register
numbers manually.
It is now legal to pass NoRegister to isPhysicalRegister() and
isVirtualRegister(). The result is false in both cases.
It is quite rare to represent stack slots in this way, so isPhysicalRegister()
and isVirtualRegister() require that isStackSlot() be checked first if it can
possibly return true. This allows a very fast implementation of the common
predicates.
llvm-svn: 123137
physical register numbers.
This makes the hack used in LiveInterval official, and lets LiveInterval be
oblivious of stack slots.
The isPhysicalRegister() and isVirtualRegister() predicates don't know about
this, so when a variable may contain a stack slot, isStackSlot() should always
be tested first.
llvm-svn: 123128
Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.
llvm-svn: 123107
Provide MRI::getNumVirtRegs() and TRI::index2VirtReg() functions to allow
iteration over virtual registers without depending on the representation of
virtual register numbers.
llvm-svn: 123098
may be called. If the entry block is empty, the insertion point iterator will be
the "end()" value. Calling ->getParent() on it (among others) causes problems.
Modify materializeFrameBaseRegister to take the machine basic block and insert
the frame base register at the beginning of that block. (It's very similar to
what the code does all ready. The only difference is that it will always insert
at the beginning of the entry block instead of after a previous materialization
of the frame base register. I doubt that that matters here.)
<rdar://problem/8782198>
llvm-svn: 122104
registers that alias Reg, including itself. This is almost the same as the
existing getAliasSet() method, except for the inclusion of Reg.
The name matches the reflexive TRI::regsOverlap(x, y) relation.
It is very common to do stuff to a register and all its aliases:
stuff(Reg)
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
stuff(*Alias);
That can now be written as the simpler:
for (const unsigned *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias)
stuff(*Alias);
This change requires a bit more constant space for the alias lists because Reg
is included and because the empty alias list cannot be shared any longer.
If the getAliasSet method is eventually removed, this space can be reclaimed by
sharing overlap lists. For instance, %rax and %eax have identical overlap sets.
llvm-svn: 121800
Nothing fancy, just ask the target if any currently available base reg
is in range for the instruction under consideration and use the first one
that is. Placeholder ARM implementation simply returns false for now.
ongoing saga of rdar://8277890
llvm-svn: 111374
the local block. Resolve references to those indices to a new base register.
For simplification and testing purposes, a new virtual base register is
allocated for each frame index being resolved. The result is truly horrible,
but correct, code that's good for exercising the new code paths.
Next up is adding thumb1 support, which should be very simple. Following that
will be adding base register re-use and implementing a reasonable ARM
heuristic for when a virtual base register should be generated at all.
llvm-svn: 111315
whether to allocate a virtual frame base register to resolve the frame
index reference in it. Implement a simple version for ARM to aid debugging.
In LocalStackSlotAllocation, scan the function for frame index references
to local frame indices and ask the target whether to allocate virtual
frame base registers for any it encounters. Purely infrastructural for
debug output. Next step is to actually allocate base registers, then add
intelligent re-use of them.
rdar://8277890
llvm-svn: 111262
AggressiveAntiDepBreaker should not be using getPhysicalRegisterRegClass. An
instruction might be using a register that can only be replaced with one from
a subclass of getPhysicalRegisterRegClass.
With this patch we use getMinimalPhysRegClass. This is correct, but
conservative. We should check the uses of the register and select the
largest register class that can be used in all of them.
llvm-svn: 108122
of getPhysicalRegisterRegClass with it.
If we want to make a copy (or estimate its cost), it is better to use the
smallest class as more efficient operations might be possible.
llvm-svn: 107140
implementation that is correct for most targets. Tablegen will override where
needed.
Add MachineOperand::subst{Virt,Phys}Reg methods that correctly handle existing
subreg indices when sustituting registers.
llvm-svn: 104985
structure that represents a mapping without any dependencies on SubRegIndex
numbering.
This brings us closer to being able to remove the explicit SubRegIndex
numbering, and it is now possible to specify any mapping without inventing
*_INVALID register classes.
llvm-svn: 104563
instructions.
e.g.
%reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0
%reg1027<def> = EXTRACT_SUBREG %reg1026, 6
%reg1028<def> = EXTRACT_SUBREG %reg1026<kill>, 5
...
%reg1029<def> = REG_SEQUENCE %reg1028<kill>, 5, %reg1027<kill>, 6, %reg1028, 7, %reg1027, 8, %reg1028, 9, %reg1027, 10, %reg1030<kill>, 11, %reg1032<kill>, 12
After REG_SEQUENCE is eliminated, we are left with:
%reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0
%reg1029:6<def> = EXTRACT_SUBREG %reg1026, 6
%reg1029:5<def> = EXTRACT_SUBREG %reg1026<kill>, 5
The regular coalescer will not be able to coalesce reg1026 and reg1029 because it doesn't
know how to combine sub-register indices 5 and 6. Now 2-address pass will consult the
target whether sub-registers 5 and 6 of reg1026 can be combined to into a larger
sub-register (or combined to be reg1026 itself as is the case here). If it is possible,
it will be able to replace references of reg1026 with reg1029 + the larger sub-register
index.
llvm-svn: 103835
is preparatory to having PEI's scavenged frame index value reuse logic
properly distinguish types of frame values (e.g., whether the value is
stack-pointer relative or frame-pointer relative).
No functionality change.
llvm-svn: 98086
126.gcc nightly tests. These failures uncovered latent bugs that machine DCE
could remove one half of a stack adjust down/up pair, causing PEI to assert.
This update fixes that, and the tests now pass.
llvm-svn: 96822
