This also avoids emitting the information twice, which led to code bloat. On i386-linux-Release+Asserts
with all targets built this change shaves a whopping 1.3 MB off clang. The number is probably exaggerated
by recent inliner changes but the methods were already enormous with the old inline cost computation.
The DWARF reg -> LLVM reg mapping doesn't seem to have holes in it, so it could be a simple lookup table.
I didn't implement that optimization yet to avoid potentially changing functionality.
There is still some duplication both in tablegen and the generated code that should be cleaned up eventually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153837 91177308-0d34-0410-b5e6-96231b3b80d8
Use an explicit comparator instead of the default.
The sets are sorted, but not using the default comparator. Hopefully,
this will unbreak the Linux builders.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153772 91177308-0d34-0410-b5e6-96231b3b80d8
TableGen emits lists of sub-registers, super-registers, and overlaps. Put
them all in a single table and use a SequenceToOffsetTable to share
suffixes.
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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).
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This reverts commit 151760.
We want to move getSubReg() from TargetRegisterInfo into MCRegisterInfo,
but to do that, the type of the lookup table needs to be the same for
all targets.
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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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151806 91177308-0d34-0410-b5e6-96231b3b80d8
- The search bounds are constant, in the worst case (ARM target) it will scan over 30 uint16_ts.
- This method isn't very hot, I had problems finding a testcase where it's called more than a dozen of times (no perf impact).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151773 91177308-0d34-0410-b5e6-96231b3b80d8
Instead of nested switch statements, use a lookup table. On ARM, this replaces
a 23k (x86_64 release build) function with a 16k table. Its not unlikely to
be faster, as well.
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This class is used to represent SubRegIndex instances instead of the raw
Record pointers that were used before.
No functional change intended.
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Targets can now add CalleeSavedRegs defs to their *CallingConv.td file.
TableGen will use this to create a *_SaveList array suitable for
returning from getCalleeSavedRegs() as well as a *_RegMask bit mask
suitable for returning from getCallPreservedMask().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148346 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146873 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141258 91177308-0d34-0410-b5e6-96231b3b80d8
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.
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When TableGen starts creating its own register classes, the synthesized
classes won't have a Record reference. All register classes must have a
name, though.
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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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140898 91177308-0d34-0410-b5e6-96231b3b80d8
This can happen in cases where TableGen generated asm matcher cannot check
whether a register operand is in the right register class. e.g. mem operands.
rdar://8204588
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This makes TargetRegisterClass slightly slower. Next step will be making contains faster.
Eventually TargetRegisterClass will be killed entirely.
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to MCRegisterInfo. Also initialize the mapping at construction time.
This patch eliminate TargetRegisterInfo from TargetAsmInfo. It's another step
towards fixing the layering violation.
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MSVC decorates (and distinguishes) "const" in mangler. It brought linkage error between "extern const" declarations and definitions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135269 91177308-0d34-0410-b5e6-96231b3b80d8
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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This caused linker errors when linking both libLLVMX86Desc and libLLVMX86CodeGen
into a single binary (for example when building a monolithic libLLVM shared library).
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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.
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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.
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A register class can define AltOrders and AltOrderSelect instead of
defining method protos and bodies. The AltOrders lists can be defined
with set operations, and TableGen can verify that the alternative
allocation orders only contain valid registers.
This is currently an opt-in feature, and it is still possible to
override allocation_order_begin/end. That will not be true for long.
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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.
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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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Measure the worst case number of probes for a miss instead of the less
conservative number of probes required for an insertion.
Lower the limit to < 6 probes worst case.
This doubles the size of the ARM and X86 hash tables, other targets are
unaffected. LiveVariables runs 12% faster with this change.
<rdar://problem/9598545>
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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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132888 91177308-0d34-0410-b5e6-96231b3b80d8
The constant hash tables for sub-registers and overlaps are generated
the same way, so extract a function to generate and print the hash
table.
Also use the information computed by CodeGenRegisters.cpp instead of the
locally data.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132886 91177308-0d34-0410-b5e6-96231b3b80d8
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.
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Create a new CodeGenRegBank class that will eventually hold all the code
that computes the register structure from Records.
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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.
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same dwarf number. This will be used for creating a dwarf number to register
mapping.
The only case that needs this so far is the XMM/YMM registers that unfortunately
do have the same numbers.
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There was no way to check if a given register/mode pair was valid. We now return
an error code (-2) instead of asserting. If anyone thinks that an assert
at this point is really needed, we can autogen a hasValidDwarfRegNum instead.
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The RegisterInfo.td file should only specify the indexes that sources need to
refer to. The rest is inferred.
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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).
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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.
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