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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133216 91177308-0d34-0410-b5e6-96231b3b80d8
This avoids the manual filtering of reserved registers and removes the
dependency on allocation_order_begin().
Palliative care...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133177 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129772 91177308-0d34-0410-b5e6-96231b3b80d8
When a virtual register has a single value that is defined as a copy of a
reserved register, permit that copy to be joined. These virtual register are
usually copies of the stack pointer:
%vreg75<def> = COPY %ESP; GR32:%vreg75
MOV32mr %vreg75, 1, %noreg, 0, %noreg, %vreg74<kill>
MOV32mi %vreg75, 1, %noreg, 8, %noreg, 0
MOV32mi %vreg75<kill>, 1, %noreg, 4, %noreg, 0
CALLpcrel32 ...
Coalescing these virtual registers early decreases register pressure.
Previously, they were coalesced by RALinScan::attemptTrivialCoalescing after
register allocation was completed.
The lower register pressure causes the mcinst-lowering-cmp0.ll test case to fail
because it depends on linear scan spilling a particular register.
I am deleting 2008-08-05-SpillerBug.ll because it is counting the number of
instructions emitted, and its revision history shows the 'correct' count being
edited many times.
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Add an assertion to linear scan to prevent it from allocating registers outside
the register class.
<rdar://problem/9183021>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128254 91177308-0d34-0410-b5e6-96231b3b80d8
The SlotIndex created by the default construction does not represent a position
in the function, and it doesn't make sense to compare it to other indexes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126924 91177308-0d34-0410-b5e6-96231b3b80d8
Linear scan regalloc is currently assuming that any register aliased with
a member of a regclass must also be in at least one regclass. That is not
always true. For example, for X86, RIP is in a regclass but IP is not.
If you're unlucky, this can cause a crash by invalidating the iterator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124365 91177308-0d34-0410-b5e6-96231b3b80d8
These functions not longer assert when passed 0, but simply return false instead.
No functional change intended.
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proper SSA updating.
This doesn't cause MachineDominators to be recomputed since we are already
requiring MachineLoopInfo which uses dominators as well.
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must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize
the pass's dependencies.
Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.
I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems
with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass
registration/creation, please send the testcase to me directly.
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perform initialization without static constructors AND without explicit initialization
by the client. For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve. I hope to be able to relax
the latter requirement in the future.
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The earliestStart argument is entirely specific to linear scan allocation, and
can be easily calculated by RegAllocLinearScan.
Replace std::vector with SmallVector.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111055 91177308-0d34-0410-b5e6-96231b3b80d8
The spillers can pluck the analyses they need from the pass reference.
Switch some never-null pointers to references.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108969 91177308-0d34-0410-b5e6-96231b3b80d8
EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.
Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.
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