Prepare it for vectors of pointers and handle simple cases. We don't handle
complicated cases because accumulateConstantOffset bails on pointer vectors.
Fixes selfhost on i386.
llvm-svn: 174179
remaining use of AliasAnalysis concepts such as isIdentifiedObject to
prove pointer inequality.
@external_compare in test/Transforms/InstSimplify/compare.ll shows a simple
case where a noalias argument can be equal to a global variable address, and
while AliasAnalysis can get away with saying that these pointers don't alias,
instsimplify cannot say that they are not equal.
llvm-svn: 174122
We use constant folding to see if an intrinsic evaluates to the same value as a
constant that we know. If we don't take the undefinedness into account we get a
value that doesn't match the actual implementation, and miscompiled code.
This was uncovered by Chandler's simplifycfg changes.
llvm-svn: 173356
generic function calls and intrinsics. This is somewhat overlapping with
an existing intrinsic cost method, but that one seems targetted at
vector intrinsics. I'll merge them or separate their names and use cases
in a separate commit.
This sinks the test of 'callIsSmall' down into TTI where targets can
control it. The whole thing feels very hack-ish to me though. I've left
a FIXME comment about the fundamental design problem this presents. It
isn't yet clear to me what the users of this function *really* care
about. I'll have to do more analysis to figure that out. Putting this
here at least provides it access to proper analysis pass tools and other
such. It also allows us to more cleanly implement the baseline cost
interfaces in TTI.
With this commit, it is now theoretically possible to simplify much of
the inline cost analysis's handling of calls by calling through to this
interface. That conversion will have to happen in subsequent commits as
it requires more extensive restructuring of the inline cost analysis.
The CodeMetrics class is now really only in the business of running over
a block of code and aggregating the metrics on that block of code, with
the actual cost evaluation done entirely in terms of TTI.
llvm-svn: 173148
Previously we tried to infer it from the bit width size, with an added
IsIEEE argument for the PPC/IEEE 128-bit case, which had a default
value. This default value allowed bugs to creep in, where it was
inappropriate.
llvm-svn: 173138
is free. The whole CodeMetrics API should probably be reworked more, but
this is enough to allow deleting the duplicate code there for computing
whether an instruction is free.
All of the passes using this have been updated to pull in TTI and hand
it to the CodeMetrics stuff. Further, a dead CodeMetrics API
(analyzeFunction) is nuked for lack of users.
llvm-svn: 173036
analysis. How cute that it wasn't previously. ;]
Part of this confusion stems from the flattened header file tree. Thanks
to Benjamin for pointing out the goof on IRC, and we're considering
un-flattening the headers, so speak now if that would bug you.
llvm-svn: 173033
old CodeMetrics system. TTI has the specific advantage of being
extensible and customizable by targets to reflect target-specific cost
metrics.
llvm-svn: 173032
depend on and use other analyses (as long as they're either immutable
passes or CGSCC passes of course -- nothing in the pass manager has been
fixed here). Leverage this to thread TargetTransformInfo down through
the inline cost analysis.
No functionality changed here, this just threads things through.
llvm-svn: 173031
a dynamic analysis done on each call to the routine. However, now it can
use the standard pass infrastructure to reference other analyses,
instead of a silly setter method. This will become more interesting as
I teach it about more analysis passes.
This updates the two inliner passes to use the inline cost analysis.
Doing so highlights how utterly redundant these two passes are. Either
we should find a cheaper way to do always inlining, or we should merge
the two and just fiddle with the thresholds to get the desired behavior.
I'm leaning increasingly toward the latter as it would also remove the
Inliner sub-class split.
llvm-svn: 173030
lowered cost.
Currently, this is a direct port of the logic implementing
isInstructionFree in CodeMetrics. The hope is that the interface can be
improved (f.ex. supporting un-formed instruction queries) and the
implementation abstracted so that as we have test cases and target
knowledge we can expose increasingly accurate heuristics to clients.
I'll start switching existing consumers over and kill off the routine in
CodeMetrics in subsequent commits.
llvm-svn: 172998
Okay, here's how to reproduce the problem:
1) Build a Release (or Release+Asserts) version of clang in the normal way.
2) Using the clang & clang++ binaries from (1), build a Release (or
Release+Asserts) version of the same sources, but this time enable LTO ---
specify the `-flto' flag on the command line.
3) Run the ARC migrator tests:
$ arcmt-test --args -triple x86_64-apple-darwin10 -fsyntax-only -x objective-c++ ./src/tools/clang/test/ARCMT/cxx-rewrite.mm
You'll see that the output isn't correct (the whitespace is off).
The mis-compile is in the function `RewriteBuffer::RemoveText' in the
clang/lib/Rewrite/Core/Rewriter.cpp file. When that function and RewriteRope.cpp
are compiled with LTO and the `arcmt-test' executable is regenerated, you'll see
the error. When those files are not LTO'ed, then the output of the `arcmt-test'
is fine.
It is *really* hard to get a testcase out of this. I'll file a PR with what I
have currently.
--- Reverse-merging r172363 into '.':
U include/llvm/Analysis/MemoryBuiltins.h
U lib/Analysis/MemoryBuiltins.cpp
--- Reverse-merging r171325 into '.':
U test/Transforms/InstCombine/objsize.ll
G include/llvm/Analysis/MemoryBuiltins.h
G lib/Analysis/MemoryBuiltins.cpp
llvm-svn: 172756
Moving the X86CostTable to a common place, so that other back-ends
can share the code. Also simplifying it a bit and commoning up
tables with one and two types on operations.
llvm-svn: 172658
TargetTransformInfo rather than TargetLowering, removing one of the
primary instances of the layering violation of Transforms depending
directly on Target.
This is a really big deal because LSR used to be a "special" pass that
could only be tested fully using llc and by looking at the full output
of it. It also couldn't run with any other loop passes because it had to
be created by the backend. No longer is this true. LSR is now just
a normal pass and we should probably lift the creation of LSR out of
lib/CodeGen/Passes.cpp and into the PassManagerBuilder. =] I've not done
this, or updated all of the tests to use opt and a triple, because
I suspect someone more familiar with LSR would do a better job. This
change should be essentially without functional impact for normal
compilations, and only change behvaior of targetless compilations.
The conversion required changing all of the LSR code to refer to the TTI
interfaces, which fortunately are very similar to TargetLowering's
interfaces. However, it also allowed us to *always* expect to have some
implementation around. I've pushed that simplification through the pass,
and leveraged it to simplify code somewhat. It required some test
updates for one of two things: either we used to skip some checks
altogether but now we get the default "no" answer for them, or we used
to have no information about the target and now we do have some.
I've also started the process of removing AddrMode, as the TTI interface
doesn't use it any longer. In some cases this simplifies code, and in
others it adds some complexity, but I think it's not a bad tradeoff even
there. Subsequent patches will try to clean this up even further and use
other (more appropriate) abstractions.
Yet again, almost all of the formatting changes brought to you by
clang-format. =]
llvm-svn: 171735
reachablity.
We conservatively approximate the reachability analysis by saying it is not
reachable if there is a single path starting from "From" and the path does not
reach "To".
rdar://12801584
llvm-svn: 171512
code that includes Intrinsics.gen directly.
This never showed up in my testing because the old Intrinsics.gen was
still kicking around in the make build system and was correct there. =[
Thankfully, some of the bots to clean rebuilds and that caught this.
llvm-svn: 171373
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
llvm-svn: 171366
Aside from moving the actual files, this patch only updates the build
system and the source file comments under lib/... that are relevant.
I'll be updating other docs and other files in smaller subsequnet
commits.
While I've tried to test this, but it is entirely possible that there
will still be some build system fallout.
Also, note that I've not changed the library name itself: libLLVMCore.a
is still the library name. I'd be interested in others' opinions about
whether we should rename this as well (I think we should, just not sure
what it might break)
llvm-svn: 171359
The new code is an improved copy of the code I deleted from Analysis/Loads.cpp.
One less compute-constant-gep-offset implementation. yay :)
llvm-svn: 171326
The later API is nicer than the former, and is correct regarding wrap-around offsets (if anyone cares).
There are a few more places left with duplicated code, which I'll remove soon.
llvm-svn: 171259
directly.
This is in preparation for removing the use of the 'Attribute' class as a
collection of attributes. That will shift to the AttributeSet class instead.
llvm-svn: 171253
propagating one of the values it simplified to a constant across
a myriad of instructions. Notably, ptrtoint instructions when we had
a constant pointer (say, 0) didn't propagate that, blocking a massive
number of down-stream optimizations.
This was uncovered when investigating why we fail to inline and delete
the boilerplate in:
void f() {
std::vector<int> v;
v.push_back(1);
}
It turns out most of the efforts I've made thus far to improve the
analysis weren't making it far purely because of this. After this is
fixed, the store-to-load forwarding patch enables LLVM to optimize the
above to an empty function. We still can't nuke a second push_back, but
for different reasons.
There is a very real chance this will cause somewhat noticable changes
in inlining behavior, so please let me know if you see regressions (or
improvements!) because of this patch.
llvm-svn: 171196
how to propagate constants through insert and extract value
instructions.
With the recent improvements to instsimplify, this allows inline cost
analysis to constant fold through intrinsic functions, including notably
the with.overflow intrinsic math routines which often show up inside of
STL abstractions. This is yet another piece in the puzzle of breaking
down the code for:
void f() {
std::vector<int> v;
v.push_back(1);
}
But it still isn't enough. There are a pile of bugs in inline cost still
blocking this.
llvm-svn: 171195
constant folding calls. Add the initial tests for this which show that
now instsimplify can simplify blindingly obvious code patterns expressed
with both intrinsics and library calls.
llvm-svn: 171194
are nice and decomposed so that we can simplify synthesized calls as
easily as actually call instructions. The internal utility still has the
same behavior, it just now operates on a more generic interface so that
I can extend the set of call simplifications that instsimplify knows
about.
llvm-svn: 171189
When the backend is used from clang, it should produce proper diagnostics
instead of just printing messages to errs(). Other clients may also want to
register their own error handlers with the LLVMContext, and the same handler
should work for warnings in the same way as the existing emitError methods.
llvm-svn: 171041
Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage).
llvm-svn: 170704
I introduced it in r166785. PR14291.
If TD is unavailable use getScalarSizeInBits, but don't optimize
pointers or vectors of pointers.
llvm-svn: 170586
In a previous thread it was pointed out that isPowerOfTwo is not a very precise
name since it can return false for powers of two if it is unable to show that
they are powers of two.
llvm-svn: 170093
been used in the first place. It simply was passed to the function and to the
recursive invocations. Simply drop the parameter and update the callers for the
new signature.
Patch by Saleem Abdulrasool!
llvm-svn: 169988
fsub X, +0 ==> X
fsub X, -0 ==> X, when we know X is not -0
fsub +/-0.0, (fsub -0.0, X) ==> X
fsub nsz +/-0.0, (fsub +/-0.0, X) ==> X
fsub nnan ninf X, X ==> 0.0
fadd nsz X, 0 ==> X
fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
where nnan and ninf have to occur at least once somewhere in this expression
fmul X, 1.0 ==> X
llvm-svn: 169940
instead of the instruction. I've left a forwarding wrapper for the
instruction so users with the instruction don't need to create
a GEPOperator themselves.
This lets us remove the copy of this code in instsimplify.
I've looked at most of the other copies of similar code, and this is the
only one I've found that is actually exactly the same. The one in
InlineCost is very close, but it requires re-mapping non-constant
indices through the cost analysis value simplification map. I could add
direct support for this to the generic routine, but it seems overly
specific.
llvm-svn: 169853
the GEP instruction class.
This is part of the continued refactoring and cleaning of the
infrastructure used by SROA. This particular operation is also done in
a few other places which I'll try to refactor to share this
implementation.
llvm-svn: 169852
Analyse Phis under the starting assumption that they are NoAlias. Recursively
look at their inputs.
If they MayAlias/MustAlias there must be an input that makes them so.
Addresses bug 14351.
llvm-svn: 169788
This visitor provides infrastructure for recursively traversing the
use-graph of a pointer-producing instruction like an alloca or a malloc.
It maintains a worklist of uses to visit, so it can handle very deep
recursions. It automatically looks through instructions which simply
translate one pointer to another (bitcasts and GEPs). It tracks the
offset relative to the original pointer as long as that offset remains
constant and exposes it during the visit as an APInt offset. Finally, it
performs conservative escape analysis.
However, currently it has some limitations that should be addressed
going forward:
1) It doesn't handle vectors of pointers.
2) It doesn't provide a cheaper visitor when the constant offset
tracking isn't needed.
3) It doesn't support non-instruction pointer values.
The current functionality is exactly what is required to implement the
SROA pointer-use visitors in terms of this one, rather than in terms of
their own ad-hoc base visitor, which was always very poorly specified.
SROA has been converted to use this, and the code there deleted which
this utility now provides.
Technically speaking, using this new visitor allows SROA to handle a few
more cases than it previously did. It is now more aggressive in ignoring
chains of instructions which look like they would defeat SROA, but in
fact do not because they never result in a read or write of memory.
While this is "neat", it shouldn't be interesting for real programs as
any such chains should have been removed by others passes long before we
get to SROA. As a consequence, I've not added any tests for these
features -- it shouldn't be part of SROA's contract to perform such
heroics.
The goal is to extend the functionality of this visitor going forward,
and re-use it from passes like ASan that can benefit from doing
a detailed walk of the uses of a pointer.
Thanks to Ben Kramer for the code review rounds and lots of help
reviewing and debugging this patch.
llvm-svn: 169728
by virtue of inbounds GEPs that preclude a null pointer.
This is a very common pattern in the code generated by std::vector and
other standard library routines which use allocators that test for null
pervasively. This is one step closer to teaching Clang+LLVM to be able
to produce an empty function for:
void f() {
std::vector<int> v;
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(4);
}
Which is related to getting them to completely fold SmallVector
push_back sequences into constants when inlining and other optimizations
make that a possibility.
llvm-svn: 169573
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
depends on the IR infrastructure, there is no sense in it being off in
Support land.
This is in preparation to start working to expand InstVisitor into more
special-purpose visitors that are still generic and can be re-used
across different passes. The expansion will go into the Analylis tree
though as nothing in VMCore needs it.
llvm-svn: 168972
If the Src and Dst are the same instruction,
no loop-independent dependence is possible,
so we force the PossiblyLoopIndependent flag to false.
The test case results are updated appropriately.
llvm-svn: 168678
Added in first optimization using fast-math flags to serve as an example for following optimizations. SimplifyInstruction will now try to optimize an fmul observing its FastMathFlags to see if it can fold multiply by zero when 'nnan' and 'nsz' flags are set.
llvm-svn: 168648
analysis. Better is to look for cases with useful GEPs and use them
when possible. When a pair of useful GEPs is not available, use the
raw SCEVs directly. This approach supports better analysis of pointer
dereferencing.
In parallel, all the test cases are updated appropriately.
Cases where we have a store to *B++ can now be analyzed!
llvm-svn: 168474
so that I can (someday) call SE->getSCEV without complaint.
No semantic change intended.
Patch from Preston Briggs <preston.briggs@gmail.com>.
llvm-svn: 168391
This patch moves the isInlineViable function from the InlineAlways pass into
the InlineCostAnalyzer and then changes the InlineCost computation to use that
simple check for always-inline functions. All the special-case checks for
AlwaysInline in the CallAnalyzer can then go away.
llvm-svn: 168300
This is a partial solution to PR14351. It removes some of the special
significance of the first incoming phi value in the phi aliasing checking logic
in BasicAA. In the context of a loop, the old logic assumes that the first
incoming value is the interesting one (meaning that it is the one that comes
from outside the loop), but this is often not the case. With this change, we
now test first the incoming value that comes from a block other than the parent
of the phi being tested.
llvm-svn: 168245
'nocapture' attribute.
The nocapture attribute only specifies that no copies are made that
outlive the function. This isn't the same as there being no copies at all.
This fixes PR14045.
llvm-svn: 167381
