generates the dwarf Compile Unit DIE and a dwarf subprogram DIE for each
non-temporary label.
The next part will be to get the clang driver to enable this when assembling
a .s file. rdar://9275556
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Patch by Brendon Cahoon!
This extends the existing LoopUnroll and LoopUnrollPass. Brendon
measured no regressions in the llvm test suite with -unroll-runtime
enabled. This implementation works by using the existing loop
unrolling code to unroll the loop by a power-of-two (default 8). It
generates an if-then-else sequence of code prior to the loop to
execute the extra iterations before entering the unrolled loop.
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clients to decide whether to look inside bundled instructions and whether
the query should return true if any / all bundled instructions have the
queried property.
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files. First, add a new block USELIST_BLOCK to the bitcode format. This is
where USELIST_CODE_ENTRYs will be stored. The format of the USELIST_CODE_ENTRYs
have not yet been defined. Add support in the BitcodeReader for parsing the
USELIST_BLOCK.
Part of rdar://9860654 and PR5680.
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generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.
For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.
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This flag is used when bundling machine instructions. It indicates
whether the operand reads a value defined inside or outside its bundle.
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For example, ARM allows:
vmov.u32 s4, #0 -> vmov.i32, #0
'u32' is a more specific designator for the 32-bit integer type specifier
and is legal for any instruction which accepts 'i32' as a datatype suffix.
We want to say,
def : TokenAlias<".u32", ".i32">;
This works by marking the match class of 'From' as a subclass of the
match class of 'To'.
rdar://10435076
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1. Added opcode BUNDLE
2. Taught MachineInstr class to deal with bundled MIs
3. Changed MachineBasicBlock iterator to skip over bundled MIs; added an iterator to walk all the MIs
4. Taught MachineBasicBlock methods about bundled MIs
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This was actually a bit of a mess. TLI.setPrefLoopAlignment was clearly
documented as taking log2(bytes) units, but the x86 target would still
set a preferred loop alignment of '16'.
CodePlacementOpt passed this number on to the basic block, and
AsmPrinter interpreted it as bytes.
Now both MachineFunction and MachineBasicBlock use logarithmic
alignments.
Obviously, MachineConstantPool still measures alignments in bytes, so we
can emulate the thrill of using as.
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Whether a fixup needs relaxation for the associated instruction is a
target-specific function, as the FIXME indicated. Create a hook for that
and use it.
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memory fences) in statistics registration, which works the same way that
ManagedStatic registration does.
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This is a patch by Guoping Long!
As part of utilizing LLVM Dominator computation in Clang, made two changes to LLVM dominators tree implementation:
- (1) Change the recalculate() template function to only rely on GraphTraits.
- (2) Add a size() method to GraphTraits template class to query the number of nodes in the graph.
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change, now you need a TargetOptions object to create a TargetMachine. Clang
patch to follow.
One small functionality change in PTX. PTX had commented out the machine
verifier parts in their copy of printAndVerify. That now calls the version in
LLVMTargetMachine. Users of PTX who need verification disabled should rely on
not passing the command-line flag to enable it.
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It was getting ignored after r144788.
Also fix an accidental implicit cast from the OptLevel enum
to an optional bool argument. MSVC warned on this, but gcc
didn't.
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as MC is the only assembler we support.
This splits MS/Windows and GNU/Windows ASM infos into two seperate classes.
While there is currently only one difference, full MS C++ ABI support will
require many more.
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Now that it needs to be exported in a public header (Valgrind.h)
it should be prefixed to avoid collision with other projects.
Add it to llvm-config.h as well.
This'll require regenerating the configure script after this
commit, but I don't have the required autoconf version.
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It was out of sync with the description in configure.ac/config.h.in.
Also re-alphabetize it from its position when it was LLVM_HOST_TRIPLE.
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I think this is the last of autoupgrade that can be removed in 3.1.
Can the atomic upgrade stuff also go?
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tablegen patterns for scalar FMA4 operations and intrinsic. Also
add tests for vfmaddsd.
Patch by Jan Sjodin
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and code model. This eliminates the need to pass OptLevel flag all over the
place and makes it possible for any codegen pass to use this information.
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It triggers generating insane executables with both binutils-2.19.1(msysgit) and 2.22.51.20111013(cygwin).
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Two new TargetInstrInfo hooks lets the target tell ExecutionDepsFix
about instructions with partial register updates causing false unwanted
dependencies.
The ExecutionDepsFix pass will break the false dependencies if the
updated register was written in the previoius N instructions.
The small loop added to sse-domains.ll runs twice as fast with
dependency-breaking instructions inserted.
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and stores capture) to permit the caller to see each capture point and decide
whether to continue looking.
Use this inside memdep to do an analysis that basicaa won't do. This lets us
solve another devirtualization case, fixing PR8908!
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These annotations are disabled entirely when either ENABLE_THREADS is off, or
building a release build. When enabled, they add calls to functions with no
statements to ManagedStatic's getters.
Use these annotations to inform tsan that the race used inside ManagedStatic
initialization is actually benign. Thanks to Kostya Serebryany for helping
write this patch!
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time it is queried to compute the probability of a single successor.
This makes computing the probability of every successor of a block in
sequence... really really slow. ;] This switches to a linear walk of the
successors rather than a quadratic one. One of several quadratic
behaviors slowing this pass down.
I'm not really thrilled with moving the sum code into the public
interface of MBPI, but I don't (at the moment) have ideas for a better
interface. My direction I'm thinking in for a better interface is to
have MBPI actually retain much more state and make *all* of these
queries cheap. That's a lot of work, and would require invasive changes.
Until then, this seems like the least bad (ie, least quadratic)
solution. Suggestions welcome.
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correctly handle blocks whose successor weights sum to more than
UINT32_MAX. This is slightly less efficient, but the entire thing is
already linear on the number of successors. Calling it within any hot
routine is a mistake, and indeed no one is calling it. It also
simplifies the code.
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the sum of the edge weights not overflowing uint32, and crashed when
they did. This is generally safe as BranchProbabilityInfo tries to
provide this guarantee. However, the CFG can get modified during codegen
in a way that grows the *sum* of the edge weights. This doesn't seem
unreasonable (imagine just adding more blocks all with the default
weight of 16), but it is hard to come up with a case that actually
triggers 32-bit overflow. Fortuately, the single-source GCC build is
good at this. The solution isn't very pretty, but its no worse than the
previous code. We're already summing all of the edge weights on each
query, we can sum them, check for an overflow, compute a scale, and sum
them again.
I've included a *greatly* reduced test case out of the GCC source that
triggers it. It's a pretty lame test, as it clearly is just barely
triggering the overflow. I'd like to have something that is much more
definitive, but I don't understand the fundamental pattern that triggers
an explosion in the edge weight sums.
The buggy code is duplicated within this file. I'll colapse them into
a single implementation in a subsequent commit.
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expensive the most useful interface to this analysis is.
Fun story -- it's also not correct. That's getting fixed in another
patch.
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The old naming scheme (load/use/def/store) can be traced back to an old
linear scan article, but the names don't match how slots are actually
used.
The load and store slots are not needed after the deferred spill code
insertion framework was deleted.
The use and def slots don't make any sense because we are using
half-open intervals as is customary in C code, but the names suggest
closed intervals. In reality, these slots were used to distinguish
early-clobber defs from normal defs.
The new naming scheme also has 4 slots, but the names match how the
slots are really used. This is a purely mechanical renaming, but some
of the code makes a lot more sense now.
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RegAllocGreedy has been the default for six months now.
Deleting RegAllocLinearScan makes it possible to also delete
VirtRegRewriter and clean up the spiller code.
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When this field is true it means that the load is from constant (runt-time or compile-time) and so can be hoisted from loops or moved around other memory accesses
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to fix the types section (all types, not just global types), and testcases.
The code to do the final emission is disabled by default.
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the mailing list. Suggestions for other statistics to collect would be
awesome. =]
Currently these are implemented as a separate pass guarded by a separate
flag. I'm not thrilled by that, but I wanted to be able to collect the
statistics for the old code placement as well as the new in order to
have a point of comparison. I'm planning on folding them into the single
pass if / when there is only one pass of interest.
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-g flag. In this part we generate the .file for the source being assembled and
the .loc's for the assembled instructions.
The next part will be to generate the dwarf Compile Unit DIE and a dwarf
subprogram DIE for each non-temporary label.
Once the next part is done test cases will be added. rdar://9275556
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Add a test case for the edge case that triggers this. Thanks to Chandler for bringing this to my attention.
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introduce no-return or unreachable heuristics.
The return heuristics from the Ball and Larus paper don't work well in
practice as they pessimize early return paths. The only good hitrate
return heuristics are those for:
- NULL return
- Constant return
- negative integer return
Only the last of these three can possibly require significant code for
the returning block, and even the last is fairly rare and usually also
a constant. As a consequence, even for the cold return paths, there is
little code on that return path, and so little code density to be gained
by sinking it. The places where sinking these blocks is valuable (inner
loops) will already be weighted appropriately as the edge is a loop-exit
branch.
All of this aside, early returns are nearly as common as all three of
these return categories, and should actually be predicted as taken!
Rather than muddy the waters of the static predictions, just remain
silent on returns and let the CFG itself dictate any layout or other
issues.
However, the return heuristic was flagging one very important case:
unreachable. Unfortunately it still gave a 1/4 chance of the
branch-to-unreachable occuring. It also didn't do a rigorous job of
finding those blocks which post-dominate an unreachable block.
This patch builds a more powerful analysis that should flag all branches
to blocks known to then reach unreachable. It also has better worst-case
runtime complexity by not looping through successors for each block. The
previous code would perform an N^2 walk in the event of a single entry
block branching to N successors with a switch where each successor falls
through to the next and they finally fall through to a return.
Test case added for noreturn heuristics. Also doxygen comments improved
along the way.
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two more subtle routines to the bottom and expand on their cautionary
comments a bit. No functionality or actual interface change here.
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a single class. Previously it was split between two classes, one
internal and one external. The concern seemed to center around exposing
the weights used, but those can remain confined to the implementation
file.
Having a single class to maintain the state and analyses in use will
also simplify several of the enhancements I want to make to our static
heuristics.
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to bring it under direct test instead of merely indirectly testing it in
the BlockFrequencyInfo pass.
The next step is to start adding tests for the various heuristics
employed, and to start fixing those heuristics once they're under test.
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to get important constant branch probabilities and use them for finding
the best branch out of a set of possibilities.
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block frequency analyses. This differs substantially from the existing
block-placement pass in LLVM:
1) It operates on the Machine-IR in the CodeGen layer. This exposes much
more (and more precise) information and opportunities. Also, the
results are more stable due to fewer transforms ocurring after the
pass runs.
2) It uses the generalized probability and frequency analyses. These can
model static heuristics, code annotation derived heuristics as well
as eventual profile loading. By basing the optimization on the
analysis interface it can work from any (or a combination) of these
inputs.
3) It uses a more aggressive algorithm, both building chains from tho
bottom up to maximize benefit, and using an SCC-based walk to layout
chains of blocks in a profitable ordering without O(N^2) iterations
which the old pass involves.
The pass is currently gated behind a flag, and not enabled by default
because it still needs to grow some important features. Most notably, it
needs to support loop aligning and careful layout of loop structures
much as done by hand currently in CodePlacementOpt. Once it supports
these, and has sufficient testing and quality tuning, it should replace
both of these passes.
Thanks to Nick Lewycky and Richard Smith for help authoring & debugging
this, and to Jakob, Andy, Eric, Jim, and probably a few others I'm
forgetting for reviewing and answering all my questions. Writing
a backend pass is *sooo* much better now than it used to be. =D
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AsmParser. This patch adds validation for target data layout strings upon
construction of TargetData objects. An attempt to construct a TargetData object
from a malformed string will trigger an assertion.
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Add a Value named "NAME" to each Record. This will be set to the def or defm
name when instantiating multiclasses. This will replace the #NAME# processing
hack once paste functionality is in place.
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Add a Record constructor that takes the Record name as an Init. This
is more work toward paste functionality.
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Record names may not be fully resolved at this point so ask for the
record name as a string explicitly. This avoids a potential assert.
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Allow template arg names to be Inits. This is further work to
implement paste as it allows template names to participate in paste
operations.
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Add a couple of utility functions to take a variable name and qualify
it with the namespace of the enclosing class and/or multiclass. This
is inpreparation for making template arg names first-class Inits.
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Make the VarInit name an Init itself. We need this to implement paste
functionality so we can reference variables whose names are not yet
completely resolved.
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Add accessors to get Record values by Init name. This lets us look up
Record values whose names are not yet fully resolved. More work
toward paste.
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Add a utility to get the name init and get the string representation
of the name. This will be used for paste functionality.
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Add a couple of utility functions to get at the name init and return
the name init as a string. This will be used for paste functionality.
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layer already had support for printing the results of this analysis, but
the wiring was missing.
Now that printing the analysis works, actually bring some of this
analysis, and the BranchProbabilityInfo analysis that it wraps, under
test! I'm planning on fixing some bugs and doing other work here, so
having a nice place to add regression tests and a way to observe the
results is really useful.
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Clean up the patterns, fix comments, and avoid confusing both tools
and coders. Note that the special adds/subs SelectionDAG nodes no
longer have the dummy cc_out operand.
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Some of these can be true at the same time and there are a lot to add,
so this should be turned into a bitfield. Some of the other accessors
should probably be folded into this.
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.file filenumber "directory" "filename"
This removes one join+split of the directory+filename in MC internals. Because
bitcode files have independent fields for directory and filenames in debug info,
this patch may change the .o files written by existing .bc files.
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Invalid strings in asm files will result in parse errors. Invalid string literals passed to TargetData constructors will result in an assertion.
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Some code want to check that *any* call within a function has the 'returns
twice' attribute, not just that the current function has one.
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In machine code, you can't just replaceRegWith() the same way you can
replaceAllUsesWith() in IR. Virtual registers may have different
register classes that need to be merged first.
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profile metadata at the same time. Use it to preserve metadata attached
to a branch when re-writing it in InstCombine.
Add metadata to the canonicalize_branch InstCombine test, and check that
it is tranformed correctly.
Reviewed by Nick Lewycky!
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the X86 asmparser to produce ranges in the one case that was annoying me, for example:
test.s:10:15: error: invalid operand for instruction
movl 0(%rax), 0(%edx)
^~~~~~~
It should be straight-forward to enhance filecheck, tblgen, and/or the .ll parser to use
ranges where appropriate if someone is interested.
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Just because we're dealing with a GEP doesn't mean we can assert the
SCEV has a pointer type. The fix is simply to ignore the SCEV pointer
type, which we really didn't need.
Fixes PR11138 webkit crash.
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Most instructions have some requirements for their register operands.
Usually, this is expressed as register class constraints in the
MCInstrDesc, but for inline assembly the constraints are encoded in the
flag words.
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The inline asm operand constraint is initially encoded in the virtual
register for the operand, but that register class may change during
coalescing, and the original constraint is lost.
Encode the original register class as part of the flag word for each
inline asm operand. This makes it possible to recover the actual
constraint required by inline asm, just like we can for normal
instructions.
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for cpp pre-processed assembly we give correct filename and line numbers when
reporting errors in assembly files when using clang and -integrated-as on .s
files. rdar://8998895
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141814 91177308-0d34-0410-b5e6-96231b3b80d8
file. Since it should only be used when necessary propagate it through
the backend code generation and tweak testcases accordingly.
This helps with code like in clang's test/CodeGen/debug-info-line.c where
we have multiple #line directives within a single lexical block and want
to generate only a single block that contains each file change.
Part of rdar://10246360
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141729 91177308-0d34-0410-b5e6-96231b3b80d8