Summary:
In SelectionDAG, when a store is immediately chained to another store
to the same address, elide the first store as it has no observable
effects. This is causes small improvements dealing with intrinsics
lowered to stores.
Test notes:
* Many testcases overwrite store addresses multiple times and needed
minor changes, mainly making stores volatile to prevent the
optimization from optimizing the test away.
* Many X86 test cases optimized out instructions associated with
associated with va_start.
* Note that test_splat in CodeGen/AArch64/misched-stp.ll no longer has
dependencies to check and can probably be removed and potentially
replaced with another test.
Reviewers: rnk, john.brawn
Subscribers: aemerson, rengolin, qcolombet, jyknight, nemanjai, nhaehnle, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33206
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303198 91177308-0d34-0410-b5e6-96231b3b80d8
ShrinkWrapping is a performance optimization that can safely be skipped,
so we can add `if (!skipFunction()) return;`
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303197 91177308-0d34-0410-b5e6-96231b3b80d8
This function gives the wrong answer on some non-ELF platforms in some
cases. The function that does the right thing lives in Mangler.h. To try to
discourage people from using this function, give it a different name.
Differential Revision: https://reviews.llvm.org/D33162
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303134 91177308-0d34-0410-b5e6-96231b3b80d8
Shrink-wrapping uses post-dominators to find a restore point that
post-dominates all the uses of CSR / stack.
The way dominator trees are modeled in LLVM today is that unreachable
blocks are not present in a generic dominator tree, so, an unreachable node is
dominated by anything: include/llvm/Support/GenericDomTree.h:467.
Since for post-dominators, a no-return block is considered
"unreachable", calling findNearestCommonDominator on an unreachable node
A and a non-unreachable node B, will return B, which can be false. If we
find such node, we bail out since there is no good restore point
available.
rdar://problem/30186931
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303130 91177308-0d34-0410-b5e6-96231b3b80d8
At O3 we are more willing to increase size if we believe it will improve
performance. The current threshold for tail-duplication of 2 instructions is
conservative, and can be relaxed at O3.
Benchmark results:
llvm test-suite:
6% improvement in aha, due to duplication of loop latch
3% improvement in hexxagon
2% slowdown in lpbench. Seems related, but couldn't completely diagnose.
Internal google benchmark:
Produces 4% improvement on internal google protocol buffer serialization
benchmarks.
Differential-Revision: https://reviews.llvm.org/D32324
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303084 91177308-0d34-0410-b5e6-96231b3b80d8
Currently, when masked load, store, gather or scatter intrinsics are used, we check in CodeGenPrepare pass if the subtarget support these intrinsics, if not we replace them with scalar code - this is a functional transformation not an optimization (not optional).
CodeGenPrepare pass does not run when the optimization level is set to CodeGenOpt::None (-O0).
Functional transformation should run with all optimization levels, so here I created a new pass which runs on all optimization levels and does no more than this transformation.
Differential Revision: https://reviews.llvm.org/D32487
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303050 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
We were asserting in RegisterBankInfo if RBI.copyCost() returns
UINT_MAX. This is OK for RegBankSelect::Mode::Fast since we only
try one instruction mapping and can't recover from this, but for
RegBankSelect::Mode::Greedy we will be considering multiple
instruction mappings, so we can recover if we see a UNIT_MAX copy
cost.
The copy cost for one pair of register banks in the AMDGPU backend
will be UNIT_MAX, so this patch will prevent AMDGPU tests from
breaking.
Reviewers: ab, qcolombet, t.p.northover, dsanders
Reviewed By: qcolombet
Subscribers: tpr, llvm-commits
Differential Revision: https://reviews.llvm.org/D33144
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303043 91177308-0d34-0410-b5e6-96231b3b80d8
- MIRYamlMapping: Default value provided for fields which have optional
mappings. Implemented == operators for required classes. When a field's value is
same as default value specified YAML IO class will not print it.
- MIRPrinter: Above mentioned behaviour is not on by default. If -simplify-mir
option not specified, then make yaml::Output to print fields with default values
too.
Differential Revision: https://reviews.llvm.org/D32304
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302984 91177308-0d34-0410-b5e6-96231b3b80d8
We end up dereferencing the end iterator here when the Aspect doesn't exist in the DefaultAction map.
Change the API to return Optional<LLT> and return None when not found.
Also update the callers to handle the None case
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302963 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: LiveRangeShrink pass moves instruction right after the definition with the same BB if the instruction and its operands all have more than one use. This pass is inexpensive and guarantees optimal live-range within BB.
Reviewers: davidxl, wmi, hfinkel, MatzeB, andreadb
Reviewed By: MatzeB, andreadb
Subscribers: hiraditya, jyknight, sanjoy, skatkov, gberry, jholewinski, qcolombet, javed.absar, krytarowski, atrick, spatel, RKSimon, andreadb, MatzeB, mehdi_amini, mgorny, efriedma, davide, dberlin, llvm-commits
Differential Revision: https://reviews.llvm.org/D32563
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302938 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Eli pointed out that it's unsafe to combine the shifts to ISD::SHL etc.,
because those are not defined for b > sizeof(a) * 8, even after some of
the combiners run.
However, PPCISD::SHL defines that behavior (as the instructions themselves).
Move the combination to the backend.
The tests in shift_mask.ll still pass.
Reviewers: echristo, hfinkel, efriedma, iteratee
Subscribers: nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D33076
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302937 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds min/max population count, leading/trailing zero/one bit counting methods.
The min methods return answers based on bits that are known without considering unknown bits. The max methods give answers taking into account the largest count that unknown bits could give.
Differential Revision: https://reviews.llvm.org/D32931
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302925 91177308-0d34-0410-b5e6-96231b3b80d8
CodeViewDebug sets Asm to nullptr to disable debug info generation. You
can get a .ll file like no-cus.ll from 'clang -gcodeview -g0', which
happens in the ubsan test suite.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302923 91177308-0d34-0410-b5e6-96231b3b80d8
Llvm-stress discovered that a COPY may end up in ExpandPostRA::LowerCopy()
with an undef source operand. It is not possible for the target to handle
this, as this flag is not passed to TII->copyPhysReg().
This patch solves this by treating such a COPY as an identity COPY.
Review: Matthias Braun
https://reviews.llvm.org/D32892
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302877 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Instead of using RemoveExtraEdges (which uses analyzeBranch, which cannot
always be trusted) at the end to fixup the CFG we keep the CFG updated as
we go along and remove or add branches and merge blocks.
This way we won't have any problems if the involved MBBs contain
unanalyzable instructions.
This fixes PR32721.
In that case we had a triangle
EBB
| \
| |
| TBB
| /
FBB
where FBB didn't have any successors at all since it ended with an
unconditional return. Then TBB and FBB were be merged into EBB, but EBB
would still keep its successors, and the use of analyzeBranch and
CorrectExtraCFGEdges wouldn't help to remove them since the return
instruction is not analyzable (at least not on ARM).
Reviewers: kparzysz, iteratee, MatzeB
Reviewed By: iteratee
Subscribers: aemerson, rengolin, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33037
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302876 91177308-0d34-0410-b5e6-96231b3b80d8
Turns out that the Fission/Split DWARF package format (DWP) is currently
insufficient to handle cross-CU (ref_addr) references. So for now,
duplicate any debug info needed in these situations:
* inlined_subroutine's abstract_origin
* inlined variable's abstract_origin
* types
Keep the ref_addr behavior in general, including in the split DWARF
inline debug info that can be emitted into the object files for online
symbolication.
Keep a flag to use the old (ref_addr) behavior for testing ways of
addressing this limitation in the DWP tool (& for those not using DWP
packaging).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302858 91177308-0d34-0410-b5e6-96231b3b80d8
Updates the MSP430 target to generate EABI-compatible libcall names.
As a byproduct, adjusts the hardware multiplier options available in
the MSP430 target, adds support for promotion of the ISD::MUL operation
for 8-bit integers, and correctly marks R11 as used by call instructions.
Patch by Andrew Wygle.
Differential Revision: https://reviews.llvm.org/D32676
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302820 91177308-0d34-0410-b5e6-96231b3b80d8
The testcase in PR32984 shows a non linear compile time increase
after a change that made the LoopUnroll pass more aggressive
(increasing the threshold).
My profiling shows all the time of PHI elimination goes to
llvm::LiveVariables::addNewBlock. This is because we keep
Defs/Kills registers in a SmallSet and vfind(const T &V); is O(N).
Switching to a DenseSet reduces the time spent in the pass from
297 seconds to 97 seconds. Profiling still shows a lot of time is
spent iterating the data structure, so I guess there's room for
improvement.
Dan tells me GCC uses real set operations for live registers and
it takes no-time on this testcase. Matthias points out we might
want to switch all this to LiveIntervalAnalysis so it's not entirely
sure if a rewrite is worth it.
Differential Revision: https://reviews.llvm.org/D33088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302819 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Allow consecutive stores whose values come from consecutive loads to
merged in the presense of other uses of the loads. Previously this was
disallowed as in general the merged load cannot be shared with the
other uses. Merging N stores into 1 may cause as many as N redundant
loads. However in the context of caching this should have neglible
affect on memory pressure and reduce instruction count making it
almost always a win.
Fixes PR32086.
Reviewers: spatel, jyknight, andreadb, hfinkel, efriedma
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30471
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302712 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When trying to figure out if MBB could fallthrough to ToMBB (possibly by
falling through a bunch of other MBBs) we didn't actually check if there
was fallthrough between the last two blocks in the chain.
Reviewers: kparzysz, iteratee, MatzeB
Reviewed By: kparzysz, iteratee
Subscribers: javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D32996
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302650 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
MachineRegisterInfo::constrainRegClass() can fail if two register classes
don't have a common subclass or if the register class doesn't contain
enough registers. Check the return value before trying to remove Phi nodes,
and if we can't constrain, we output a COPY instead of simply replacing
registers.
Reviewers: kparzysz, david2050, wmi
Reviewed By: kparzysz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32999
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302622 91177308-0d34-0410-b5e6-96231b3b80d8
This is a follow-up to r302611, which moved an -O0 computation of DT
from SDAGISel to TwoAddress.
Don't use it here either, and avoid computing it completely. The only
use was forwarding the analysis as an optional argument to utility
functions.
Differential Revision: https://reviews.llvm.org/D32766
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302612 91177308-0d34-0410-b5e6-96231b3b80d8
Before r247167, the pass manager builder controlled which AA
implementations were used, exporting them all in the AliasAnalysis
analysis group.
Now, AAResultsWrapperPass always uses BasicAA, but still uses other AA
implementations if made available in the pass pipeline.
But regardless, SDAGISel is required at O0, and really doesn't need to
be doing fancy optimizations based on useful AA results.
Don't require AA at CodeGenOpt::None, and only use it otherwise.
This does have a functional impact (and one testcase is pessimized
because we can't reuse a load). But I think that's desirable no matter
what.
Note that this alone doesn't result in less DT computations: TwoAddress
was previously able to reuse the DT we computed for SDAG. That will be
fixed separately.
Differential Revision: https://reviews.llvm.org/D32766
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302611 91177308-0d34-0410-b5e6-96231b3b80d8
We currently require SCEV, which requires DT/LI. Those are expensive to
compute, but the pass only runs for functions that have the safestack
attribute.
Compute DT/LI to build SCEV lazily, only when the pass is actually going
to transform the function.
Differential Revision: https://reviews.llvm.org/D31302
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302610 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes inalloca parameters, which previously all pointed to the same
offset. Extend the test to use llvm-readobj so that we can test the
offset in a readable way.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302578 91177308-0d34-0410-b5e6-96231b3b80d8
