We currently return 4 for stackmaps and patchpoints, which is very optimistic
and can in rare cases cause the branch relaxation pass to fail to relax certain
branches.
This patch causes getInstSizeInBytes to return a pessimistic estimate of the
size as the number of bytes requested in the stackmap/patchpoint. In the future,
we could provide a more accurate estimate by sharing some of the logic in
AArch64::LowerSTACKMAP/PATCHPOINT.
Fixes part of https://llvm.org/bugs/show_bug.cgi?id=28750
Differential Revision: https://reviews.llvm.org/D24073
llvm-svn: 281301
Now that MachineBasicBlock::reverse_instr_iterator knows when it's at
the end (since r281168 and r281170), implement
MachineBasicBlock::reverse_iterator directly on top of an
ilist::reverse_iterator by adding an IsReverse template parameter to
MachineInstrBundleIterator. This replaces another hard-to-reason-about
use of std::reverse_iterator on list iterators, matching the changes for
ilist::reverse_iterator from r280032 (see the "out of scope" section at
the end of that commit message). MachineBasicBlock::reverse_iterator
now has a handle to the current node and has obvious invalidation
semantics.
r280032 has a more detailed explanation of how list-style reverse
iterators (invalidated when the pointed-at node is deleted) are
different from vector-style reverse iterators like std::reverse_iterator
(invalidated on every operation). A great motivating example is this
commit's changes to lib/CodeGen/DeadMachineInstructionElim.cpp.
Note: If your out-of-tree backend deletes instructions while iterating
on a MachineBasicBlock::reverse_iterator or converts between
MachineBasicBlock::iterator and MachineBasicBlock::reverse_iterator,
you'll need to update your code in similar ways to r280032. The
following table might help:
[Old] ==> [New]
delete &*RI, RE = end() delete &*RI++
RI->erase(), RE = end() RI++->erase()
reverse_iterator(I) std::prev(I).getReverse()
reverse_iterator(I) ++I.getReverse()
--reverse_iterator(I) I.getReverse()
reverse_iterator(std::next(I)) I.getReverse()
RI.base() std::prev(RI).getReverse()
RI.base() ++RI.getReverse()
--RI.base() RI.getReverse()
std::next(RI).base() RI.getReverse()
(For more details, have a look at r280032.)
llvm-svn: 281172
This patch changes LLVM_CONSTEXPR variable declarations to const
variable declarations, since LLVM_CONSTEXPR expands to nothing if the
current compiler doesn't support constexpr. In all of the changed
cases, it looks like the code intended the variable to be const instead
of sometimes-constexpr sometimes-not.
llvm-svn: 279696
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.
llvm-svn: 278902
This re-factoring could cause the following slight changes in generated
code, though none were observed during testing:
- MachineScheduler could decide not to cluster some loads/stores if
there are other load/stores with non-pairable opcodes that have the
same base register and offset as a pairable set of load/stores. One
case of different MachineScheduler pairing did show up in my testing,
but it wasn't due to this issue, but due
BaseMemOpClusterMutation::clusterNeighboringMemOps() being unstable
w.r.t. the order it considers memory operations. See PR28942.
- The ImplicitNullChecks optimization could be done for more load/store
opcodes. This optimization isn't done for C/C++ code, so it didn't
show up in my testing.
Reviewers: mcrosier, t.p.northover
Subscribers: aemerson, rengolin, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D23365
llvm-svn: 278515
The branch relaxation pass is computing the wrong offsets because it assumes
TLSDESC_CALLSEQ eats up 4 bytes, when in fact it is lowered to an instruction
sequence taking up 16 bytes. This can become a problem in huge files with lots
of TLS accesses, as it may slowly move branch targets out of the range computed
by the branch relaxation pass.
Fixes PR24234 https://llvm.org/bugs/show_bug.cgi?id=24234
Differential Revision: https://reviews.llvm.org/D22870
llvm-svn: 277331
If a subtarget has both ZCZeroing and CustomCheapAsMoveHandling features (now
only Kryo has both), set COPY (W|X)ZR isAsCheapAsAMove.
Differential Revision: http://reviews.llvm.org/D22360
llvm-svn: 275503
Summary:
Make the target-specific flags in MachineMemOperand::Flags real, bona
fide enum values. This simplifies users, prevents various constants
from going out of sync, and avoids the false sense of security provided
by declaring static members in classes and then forgetting to define
them inside of cpp files.
Reviewers: MatzeB
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D22372
llvm-svn: 275451
Summary:
- Give it a shorter name (because we're going to refer to it often from
SelectionDAG and friends).
- Split the flags and alignment into separate variables.
- Specialize FlagsEnumTraits for it, so we can do bitwise ops on it
without losing type information.
- Make some enum values constants in MachineMemOperand instead.
MOMaxBits should not be a valid Flag.
- Simplify some of the bitwise ops for dealing with Flags.
Reviewers: chandlerc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22281
llvm-svn: 275438
If a subtarget has both ZCZeroing and CustomCheapAsMoveHandling features (now
only Kryo has both), set FMOVS0 and FMOVD0 isAsCheapAsAMove.
Differential Revision: http://reviews.llvm.org/D22256
llvm-svn: 275178
Avoid implicit conversions from MachineInstrBundleInstr to MachineInstr*
in the AArch64 backend, mainly by preferring MachineInstr& over
MachineInstr* when a pointer isn't nullable.
llvm-svn: 274924
This is mostly a mechanical change to make TargetInstrInfo API take
MachineInstr& (instead of MachineInstr* or MachineBasicBlock::iterator)
when the argument is expected to be a valid MachineInstr. This is a
general API improvement.
Although it would be possible to do this one function at a time, that
would demand a quadratic amount of churn since many of these functions
call each other. Instead I've done everything as a block and just
updated what was necessary.
This is mostly mechanical fixes: adding and removing `*` and `&`
operators. The only non-mechanical change is to split
ARMBaseInstrInfo::getOperandLatencyImpl out from
ARMBaseInstrInfo::getOperandLatency. Previously, the latter took a
`MachineInstr*` which it updated to the instruction bundle leader; now,
the latter calls the former either with the same `MachineInstr&` or the
bundle leader.
As a side effect, this removes a bunch of MachineInstr* to
MachineBasicBlock::iterator implicit conversions, a necessary step
toward fixing PR26753.
Note: I updated WebAssembly, Lanai, and AVR (despite being
off-by-default) since it turned out to be easy. I couldn't run tests
for AVR since llc doesn't link with it turned on.
llvm-svn: 274189
This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.
llvm-svn: 272512
Testing for specific CPUs has a number of problems, better use subtarget
features:
- When some tweak is added for a specific CPU it is often desirable for
the next version of that CPU as well, yet we often forget to add it.
- It is hard to keep track of checks scattered around the target code;
Declaring all target specifics together with the CPU in the tablegen
file is a clear representation.
- Subtarget features can be tweaked from the command line.
To discourage people from using CPU checks in the future I removed the
isCortexXX(), isCyclone(), ... functions. I added an getProcFamily()
function for exceptional circumstances but made it clear in the comment
that usage is discouraged.
Reformat feature list in AArch64.td to have 1 feature per line in
alphabetical order to simplify merging and sorting for out of tree
tweaks.
No functional change intended.
Differential Revision: http://reviews.llvm.org/D20762
llvm-svn: 271555
A constant pool holding the address of a variable in equivalent to
a got entry. It produces exactly the same instruction sequence as a
got use and unlike a got use this is not uniqued by the linker.
llvm-svn: 271311
SystemZ (and probably other targets as well) can fold a memory operand
by changing the opcode into a new instruction that as a side-effect
also clobbers the CC-reg.
In order to do this, liveness of that reg must first be checked. When
LIS is passed, getRegUnit() can be called on it and the right
LiveRange is computed on demand.
Reviewed by Matthias Braun.
http://reviews.llvm.org/D19861
llvm-svn: 269026
Summary:
If a function needs to allocate both callee-save stack memory and local
stack memory, we currently decrement/increment the SP in two steps:
first for the callee-save area, and then for the local stack area. This
changes the code to allocate them both at once at the very beginning/end
of the function. This has two benefits:
1) there is one fewer sub/add micro-op in the prologue/epilogue
2) the stack adjustment instructions act as a scheduling barrier, so
moving them to the very beginning/end of the function increases post-RA
scheduler's ability to move instructions (that only depend on argument
registers) before any of the callee-save stores
This change can cause an increase in instructions if the original local
stack SP decrement could be folded into the first store to the stack.
This occurs when the first local stack store is to stack offset 0. In
this case we are trading off one more sub instruction for one fewer sub
micro-op (along with benefits (2) and (3) above).
Reviewers: t.p.northover
Subscribers: aemerson, rengolin, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18619
llvm-svn: 268746
log2(Mask) is smaller than 32, we must use the 32-bit variant because the 64-bit
variant cannot encode it. Therefore, set the subreg part accordingly.
[AArch64] Fix optimizeCondBranch logic.
The opcode for the optimized branch does not depend on the size
of the activate bits in the AND masks, but the AND opcode itself.
Indeed, we need to use a X or W variant based on the AND variant
not based on whether the mask fits into the related variant.
Otherwise, we may end up using the W variant of the optimized branch
for 64-bit register inputs!
This fixes the last make check verifier issues for AArch64: PR27479.
llvm-svn: 267465
The original patch caused crashes because it could derefence a null pointer
for SelectionDAGTargetInfo for targets that do not define it.
Evaluates fmul+fadd -> fmadd combines and similar code sequences in the
machine combiner. It adds support for float and double similar to the existing
integer implementation. The key features are:
- DAGCombiner checks whether it should combine greedily or let the machine
combiner do the evaluation. This is only supported on ARM64.
- It gives preference to throughput over latency: the heuristic used is
to combine always in loops. The targets decides whether the machine
combiner should optimize for throughput or latency.
- Supports for fmadd, f(n)msub, fmla, fmls patterns
- On by default at O3 ffast-math
llvm-svn: 267328
The opcode for the optimized branch does not depend on the size
of the activate bits in the AND masks, but the AND opcode itself.
Indeed, we need to use a X or W variant based on the AND variant
not based on whether the mask fits into the related variant.
Otherwise, we may end up using the W variant of the optimized branch
for 64-bit register inputs!
This fixes the last make check verifier issues for AArch64: PR27479.
llvm-svn: 267206
Evaluates fmul+fadd -> fmadd combines and similar code sequences in the
machine combiner. It adds support for float and double similar to the existing
integer implementation. The key features are:
- DAGCombiner checks whether it should combine greedily or let the machine
combiner do the evaluation. This is only supported on ARM64.
- It gives preference to throughput over latency: the heuristic used is
to combine always in loops. The targets decides whether the machine
combiner should optimize for throughput or latency.
- Supports for fmadd, f(n)msub, fmla, fmls patterns
- On by default at O3 ffast-math
llvm-svn: 267098
AArch64InstrInfo::optimizeCompareInstr has bug PR27158 which causes generation of incorrect code.
A compare instruction is substituted with another instruction which does not
produce the same flags as the original compare instruction.
This patch contains:
1. Fix of the bug.
2. A regression test in MIR.
3. A new test to check that SUBS is replaced by SUB.
Differential Revision: http://reviews.llvm.org/D18838
llvm-svn: 266969
This improves AA in the MI schduler when reason about paired instructions.
Phabricator Revision: http://reviews.llvm.org/D17098
PR26358
llvm-svn: 266462
Perform store clustering just like load clustering. This change add
StoreClusterMutation in machine-scheduler. To control StoreClusterMutation,
added enableClusterStores() in TargetInstrInfo.h. This is enabled only on
AArch64 for now.
This change also add support for unscaled stores which were not handled in
getMemOpBaseRegImmOfs().
llvm-svn: 266437
Disable LDP/STP for quads on Exynos M1 as they are not as efficient as pairs
of regular LDR/STR.
Patch by Abderrazek Zaafrani <a.zaafrani@samsung.com>.
llvm-svn: 266223
AArch64InstrInfo::optimizeCompareInstr has a bug which causes generation of incorrect code (PR#27158).
The patch refactors the function to simplify reviewing the fix of the bug.
1. Function name ‘modifiesConditionCode’ is changed to ‘areCFlagsAccessedBetweenInstrs’
to reflect that the function can check modifying accesses, reading accesses or both.
2. Function ‘AArch64InstrInfo::optimizeCompareInstr’
- Documented the function
- Cmp_NZCV is DeadNZCVIdx to reflect that it is an operand index of dead NZCV
- The code for the case of substituting CmpInstr is put into separate
functions the main of them is ‘substituteCmpInstr’.
Differential Revision: http://reviews.llvm.org/D18609
llvm-svn: 265531
Summary:
This change will allow loads with imp-def to be clustered in machine-scheduler pass.
areMemAccessesTriviallyDisjoint() can also handle loads with imp-def.
Reviewers: mcrosier, jmolloy, t.p.northover
Subscribers: aemerson, rengolin, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18665
llvm-svn: 265051
Matt Arsenault