Use the 3-byte (4 with REX prefix) push-pop sequence for materializing
small constants. This is smaller than using a mov (5, 6 or 7 bytes
depending on size and REX prefix), but it's likely to be slower, so
only used for 'minsize'.
This is a follow-up to r255656.
Differential Revision: http://reviews.llvm.org/D15549
llvm-svn: 255936
The current BranchProbability::normalizeProbabilities() forbids known and
unknown probabilities to coexist in the list. This was once used to help
capture probability exceptions but has caused some reported build
failures (https://llvm.org/bugs/show_bug.cgi?id=25838).
This patch removes this restriction by evenly distributing the complement
of the sum of all known probabilities to unknown ones. We could still
treat this as an abnormal behavior, but it is better to emit warnings in
our future profile validator.
Differential revision: http://reviews.llvm.org/D15548
llvm-svn: 255934
This extends the same line of reasoning used in EarlyCSE w/http://reviews.llvm.org/D15352 to the DSE implementation in InstCombine.
Key points:
* We only remove unordered or simple stores.
* The loads producing values consumed by dead stores don't influence whether the store is dead.
Differential Revision: http://reviews.llvm.org/D15354
llvm-svn: 255932
Summary:
I didn't realize that we already allowed atomic load/store of pointers,
it was added in 2012 by r162146. This patch updates the documentation
and tightens the verifier by using DataLayout to make sure that the
stored size is byte-sized and power-of-two. DataLayout is also used for
integers, and while I'm here I updated the corresponding code for
cmpxchg and rmw.
See the following discussion for context and upcoming changes to
add floating-point and vector atomics:
https://groups.google.com/forum/#!topic/llvm-dev/Nh0P_E3CRoo/discussion
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15512
llvm-svn: 255931
The rules for removing trivially dead stores are a lot less complicated than loads. Since we know the later store post dominates the former and the former dominates the later, unless the former has side effects other than the actual store, we can remove it. One slightly surprising thing is that we can freely remove atomic stores, even if the later one isn't atomic. There's no guarantee the atomic one was every visible.
For the moment, we don't handle DSE of ordered atomic stores. We could extend the same chain of reasoning to them, but the catch is we'd then have to model the ordering effect without a store instruction. Since our fences are a stronger than our operation orderings, simple using a fence isn't an obvious win. This arguable calls for a refinement in our fence specification, but that's (much) later work.
Differential Revision: http://reviews.llvm.org/D15352
llvm-svn: 255914
Summary:
Second patch split out from http://reviews.llvm.org/D14752.
Maps metadata as a post-pass from each module when importing complete,
suturing up final metadata to the temporary metadata left on the
imported instructions.
This entails saving the mapping from bitcode value id to temporary
metadata in the importing pass, and from bitcode value id to final
metadata during the metadata linking postpass.
Depends on D14825.
Reviewers: dexonsmith, joker.eph
Subscribers: davidxl, llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D14838
llvm-svn: 255909
Summary:
The method insertNOPs expected the number of wait states to be passed as
parameter, while eliminateFrameIndex passed the immediate argument for the
S_NOP, leading to an off-by-one error. Rename the method to make the
meaning of its parameter clearer. The number of 4 / 5 wait states (which
is what the method has always _tried_ to do according to the comment) is
correct according to the hardware docs.
I stumbled upon this while trying to track down the cause of
https://bugs.freedesktop.org/show_bug.cgi?id=93264. While clearly needed,
this patch unfortunately does not fix that bug...
Reviewers: arsenm, tstellarAMD
Subscribers: arsenm, llvm-commits
Differential Revision: http://reviews.llvm.org/D15542
llvm-svn: 255906
Clang has better diagnostics in this case. It is not necessary therefore
to change the destructor to avoid what is effectively an invalid warning
in gcc. Instead, better handle the warning flags given to the compiler.
llvm-svn: 255905
These days relocations are created and stored in a deterministic way.
The order they are created is also suitable for the .o file, so we don't
need an explicit sort.
The last remaining exception is MIPS.
llvm-svn: 255902
This patch enables PostRAScheduler specifically for AArch64 generic build,
which is beneficial from the performance perspective.
Speedups up to 2 to 7% for some benchmarks on A57 and A53 are observed.
Also benchmarks from LLVM test-suite did not regress.
Differential Revision: http://reviews.llvm.org/D15557
llvm-svn: 255896
This patch adds a DAG combine for (any_extend (extract_vector_elt v, i)) ->
(extract_vector_elt v, i). The combine enables us to better match some SMOV
patterns.
Differential Revision: http://reviews.llvm.org/D15515
llvm-svn: 255895
The method processFunction() is called to decide if a graph should be shown for
a certain function. To allow DOTGraphTraitViewers to take this decision based
on the analysis results for the given function, we forward a reference to the
analysis result. This will be used by Polly to only visualize functions where
interesting loop regions have been detected.
llvm-svn: 255889
Add option to enable/disable LEA optimization pass. By default the pass is disabled.
Differential Revision: http://reviews.llvm.org/D15573
llvm-svn: 255881
This creates the initial infrastructure for writing ELF output files. It
doesn't yet have any implementation for encoding instructions.
Differential Revision: http://reviews.llvm.org/D15555
llvm-svn: 255869
This is a quick fix to PR25838. The issue comes from the restriction that we
cannot normalize probabilities containing both known and unknown ones. A patch
that removes this restriction is under the review now:
http://reviews.llvm.org/D15548
llvm-svn: 255867
Introduce a new class InstrProfSymtab to abstract
the PGO symbol table for prof and coverage reader.
The symtab is is to lookup function's PGO name
using function keys. The first user of the class
is CoverageMapping Reader. More will follow.
llvm-svn: 255862
Summary:
Implement eliminateCallFramePsuedo to handle ADJCALLSTACKUP/DOWN
pseudo-instructions. Add a test calling a vararg function which causes non-0
adjustments. This revealed an issue with RegisterCoalescer wherein it
eliminates a COPY from SP32 to a vreg but failes to update the live ranges
of EXPR_STACK, causing a machineinstr verifier failure (so this test
is commented out).
Also add a dynamic alloca test, which causes a callseq_end dag node with
a 0 (instead of undef) second argument to be generated. We currently fail to
select that, so adjust the ADJCALLSTACKUP tablegen code to handle it.
Differential Revision: http://reviews.llvm.org/D15587
llvm-svn: 255844
It looks like the code this patch deletes is based on a misunderstanding of
what guarantees writev provides. In particular, writev with 1 iovec is
not "more atomic" than a write.
Testing on OS X shows that both write and writev from multiple processes
can be intermixed.
llvm-svn: 255837
This matches the other MIB methods, none of which modify the builder.
Without this, we can't chain copyImplicitOps.
Also reformat the few users, in PPCEarlyReturn.
llvm-svn: 255828
Summary: Surface counter overflow when merging profile data. Merging still occurs on overflow but counts saturate to the maximum representable value. Overflow is reported to the user.
Reviewers: davidxl, dnovillo, silvas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15547
llvm-svn: 255825
The access function has a short entry and a short exit, the initialization
block is only run the first time. To improve the performance, we want to
have a short frame at the entry and exit.
We explicitly handle most of the CSRs via copies. Only the CSRs that are not
handled via copies will be in CSR_SaveList.
Frame lowering and prologue/epilogue insertion will generate a short frame
in the entry and exit according to CSR_SaveList. The majority of the CSRs will
be handled by register allcoator. Register allocator will try to spill and
reload them in the initialization block.
We add CSRsViaCopy, it will be explicitly handled during lowering.
1> we first set FunctionLoweringInfo->SplitCSR if conditions are met (the target
supports it for the given machine function and the function has only return
exits). We also call TLI->initializeSplitCSR to perform initialization.
2> we call TLI->insertCopiesSplitCSR to insert copies from CSRsViaCopy to
virtual registers at beginning of the entry block and copies from virtual
registers to CSRsViaCopy at beginning of the exit blocks.
3> we also need to make sure the explicit copies will not be eliminated.
The target independent portion was committed as r255353.
rdar://problem/23557469
Differential Revision: http://reviews.llvm.org/D15341
llvm-svn: 255821
