optimizations when emitting calls to the function; instead those calls may
use faster relocations which require the function to be immediately resolved
upon loading the dynamic object featuring the call. This is useful when it
is known that the function will be called frequently and pervasively and
therefore there is no merit in delaying binding of the function.
Currently only implemented for x86-64, where it turns into a call through
the global offset table.
Patch by Dan Gohman, who assures me that he's going to add LangRef documentation
for this once it's committed.
llvm-svn: 133080
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
This prepares tablegen to compute register lists from set theoretic dag
expressions. This doesn't really make any difference as long as
Target.td still declares RegisterClass::MemberList as [Register].
llvm-svn: 133043
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.
llvm-svn: 133040
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>
llvm-svn: 132999
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
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.
llvm-svn: 132886
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
I'll be moving some more code there to gather all of the
register-specific stuff in one place. Currently it is shared between
CodeGenTarget and RegisterInfoEmitter.
The plan is that CodeGenRegisters can compute the full register bank
structure while RegisterInfoEmitter only will handle the printing part.
llvm-svn: 132788
A TableGen backend can define how certain classes can be expanded into
ordered sets of defs, typically by evaluating a specific field in the
record. The SetTheory class can then evaluate DAG expressions that refer
to these named sets.
A number of standard set and list operations are predefined, and the
backend can add more specialized operators if needed. The -print-sets
backend is used by SetTheory.td to provide examples.
This is intended to simplify how register classes are defined:
def GR32_NOSP : RegisterClass<"X86", [i32], 32, (sub GR32, ESP)>;
llvm-svn: 132621
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
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.
llvm-svn: 132314
switch. With this newfound organization, teach tblgen how not to give
all intrinsics the 'nounwind' attribute. Introduce a new intrinsic,
llvm.eh.resume, which does not have this attribute. Documentation and uses
to follow.
llvm-svn: 132252
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.
llvm-svn: 132236
under cmake).
Add libprofile_rt.a so that we can tell clang to link against it in --coverage
mode. Also turn it on by default in cmake builds.
Oscar, this touches a change you made for EXCLUDE_FROM_ALL support -- I think
I've done the right thing, but please let me know (or fix and commit) if not!
llvm-svn: 130470
Unfortunately, my only testcase for this is fragile, and the ARM AsmParser can't round trip the instruction in question.
<rdar://problem/9345702>
llvm-svn: 130410
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
