Summary:
The correctness fix here is that when we CSE a load with another load,
we need to combine the metadata on the two loads. This matches the
behavior of other passes, like instcombine and GVN.
There's also a minor optimization improvement here: for load PRE, the
aliasing metadata on the inserted load should be the same as the
metadata on the original load. Not sure why the old code was throwing
it away.
Issue found by inspection.
Differential Revision: http://reviews.llvm.org/D21460
llvm-svn: 277977
Sanitizers set nobuiltin attribute on certain library functions to
avoid a situation where such function is neither instrumented nor
intercepted.
At the moment the list of interesting functions is hardcoded. This
change replaces it with logic based on
TargetLibraryInfo::hasOptimizedCodegen and the presense of readnone
function attribute (sanitizers are generally interested in memory
behavior of library functions).
This is expected to be a no-op change: the new logic matches exactly
the same set of functions.
r276771 (currently reverted) added mempcpy() to the list, breaking
MSan tests. With this change, r276771 can be safely re-landed.
llvm-svn: 277086
SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.
While InstCombine canonicalizes certain undefined behavior IR patterns
to stores of undef, phase ordering means that this cannot be relied upon
in general.
There are much better tools than llvm.trap: UBSan and ASan.
N.B. I could be argued into reverting this change if a clear argument as
to why it is important that we synthesize llvm.trap for stores, I'd be
hard pressed to see why it'd be useful for invokes...
llvm-svn: 273778
r273711 was reverted by r273743. The inliner needs to know about any
call sites in the inlined function. These were obscured if we replaced
a call to undef with an undef but kept the call around.
This fixes PR28298.
llvm-svn: 273753
CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, strnlen.
When ASan/MSan/TSan/ESan is in use, this sidesteps its interceptors, resulting
in uninstrumented memory accesses. To avoid that, make these sanitizers
mark the calls as nobuiltin.
Differential Revision: http://reviews.llvm.org/D19781
llvm-svn: 273083
When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.
This change does the same to dbg.value intrinsics.
llvm-svn: 272968
We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get dangling pointer inside BranchProbabilityInfo cache.
Differential Revision: http://reviews.llvm.org/D20957
llvm-svn: 272891
Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.
llvm-svn: 270715
Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block including lifetime intrinsics as well as phi nodes and
unconditional branch into its successor or predecessor(s).
If successor of empty block has single predecessor, all contents including
lifetime intrinsics are sinked into the successor. Otherwise, they are
hoisted into its predecessor(s) and then merged into the predecessor(s).
Patch by Josh Yoon <josh.yoon@samsung.com>!
Differential Revision: http://reviews.llvm.org/D19257
llvm-svn: 268254
This moves some logic added to EarlyCSE in rL268120 into
`llvm::isInstructionTriviallyDead`. Adds a test case for DCE to
demonstrate that passes other than EarlyCSE can now pick up on the new
information.
llvm-svn: 268126
When SimplifyCFG merges identical instructions from both sides of a diamond, it
can preserve !llvm.mem.parallel_loop_access (as it does with most of the other
metadata). There's no real data or control dependency change in this case.
llvm-svn: 267515
Summary:
`llvm.guard(false)` always bails out of the current compilation unit, so
we can prune any control flow following it.
Reviewers: hfinkel, pcc, reames
Subscribers: majnemer, reames, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19245
llvm-svn: 266955
This changes RS4GC to lower calls to ``@llvm.experimental.deoptimize``
to gc.statepoints wrapping ``__llvm_deoptimize``, and changes
``callsGCLeafFunction`` to recognize ``@llvm.experimental.deoptimize``
as a non GC leaf function.
I've had to hard code the ``"__llvm_deoptimize"`` name in
RewriteStatepointsForGC; since ``TargetLibraryInfo`` is available only
during codegen. This isn't without precedent in the codebase, so I'm
not overtly concerned.
llvm-svn: 264456
I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outside ilist_iterator.
Since they depend on getNodePtrUnchecked(), they indirectly rely on UB.
This commit removes all uses of these operators. (I'll delete the
operators themselves in a separate commit so that it can be easily
reverted if necessary.)
There should be NFC here.
llvm-svn: 261498
This function is used to check whether a dbg.value intrinsic has already
been inserted, but without comparing the DIExpression, it would erroneously
fire on split aggregates and only the first scalar would survive.
Found via http://reviews.llvm.org/D16867.
<rdar://problem/24456528>
llvm-svn: 261145
SCCP has code identical to changeToUnreachable's behavior, switch it
over to just call changeToUnreachable.
No functionality change intended.
llvm-svn: 258654
InstCombine and SCCP both want to remove dead code in a very particular
way but using identical means to do so. Share the code between the two.
No functionality change is intended.
llvm-svn: 258653
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
(This is a re-commit of r257719, without the bug reported in
PR26144. I've tweaked the code to not assert-fail in
enforceKnownAlignment when computeKnownBits doesn't recurse far enough
to find the underlying Alloca/GlobalObject value.)
Differential Revision: http://reviews.llvm.org/D16145
llvm-svn: 257902
There are several requirements that ended up with this design;
1. Matching bitreversals is too heavyweight for InstCombine and doesn't really need to be done so early.
2. Bitreversals and byteswaps are very related in their matching logic.
3. We want to implement support for matching more advanced bswap/bitreverse patterns like partial bswaps/bitreverses.
4. Bswaps are best matched early in InstCombine.
The result of these is that a new utility function is created in Transforms/Utils/Local.h that can be configured to search for bswaps, bitreverses or both. InstCombine uses it to find only bswaps, CGP uses it to find only bitreversals.
We can then extend the matching logic in one place only.
llvm-svn: 257875
Summary: The dbg.declare -> dbg.value conversion did not check which operand of
the store instruction the alloca was passed to. As a result code that stored the
address of an alloca, rather than storing to the alloca, would still trigger
the conversion routine, leading to the insertion of an incorrect dbg.value
intrinsic.
Reviewers: aprantl
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16169
llvm-svn: 257787
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
llvm-svn: 257719
Summary: The dbg.declare -> dbg.value conversion looks through any zext/sext
to find a value to describe the variable (in the expectation that those
zext/sext instruction will go away later). However, those values do not
cover the entire variable and thus need a DW_OP_bit_piece.
Reviewers: aprantl
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16061
llvm-svn: 257534
JumpThreading's runOnFunction is supposed to return true if it made any
changes. JumpThreading has a call to removeUnreachableBlocks which may
result in changes to the IR but runOnFunction didn't appropriate account
for this possibility, leading to badness.
While we are here, make sure to call LazyValueInfo::eraseBlock in
removeUnreachableBlocks; JumpThreading preserves LVI.
This fixes PR26096.
llvm-svn: 257279
In r256814, we managed to remove catchpads which were trivially redudant
because they were the same SSA value. We can do better using the same
algorithm but with a smarter datastructure by hashing the SSA values
within the catchpad and comparing them structurally.
llvm-svn: 256815
Summary:
First up is instcombine, where in the dbg.declare -> dbg.value conversion,
the llvm.dbg.value needs to be called on the actual loaded value, rather
than the address (since the whole point of this transformation is to be
able to get rid of the alloca). Further, now that that's cleaned up, we
can remove a hack in the backend, that would add an implicit OP_deref if
the argument to dbg.value was an alloca. This stems from before the
existence of DIExpression and is no longer necessary since the deref can
be expressed explicitly.
Now, in order to make sure that the tests pass with this change, we need to
correct the printing of DEBUG_VALUE comments to take into account the
expression, which wasn't taken into account before.
Unfortunately, for both these changes, there were a number of incorrect
test cases (mostly the wrong number of DW_OP_derefs, but also a couple
where the test itself was broken more badly). aprantl and I have gone
through and adjusted these test case in order to make them pass with
these fixes and in some cases to make sure they're actually testing
what they are meant to test.
Reviewers: aprantl
Subscribers: dsanders
Differential Revision: http://reviews.llvm.org/D14186
llvm-svn: 256077
SimplifyCFG allows tail merging with code which terminates in
unreachable which, in turn, makes it possible for an invoke to end up in
a funclet which it was not originally part of.
Using operand bundles on invokes allows us to determine whether or not
an invoke was part of a funclet in the source program.
Furthermore, it allows us to unambiguously answer questions about the
legality of inlining into call sites which the personality may have
trouble with.
Differential Revision: http://reviews.llvm.org/D15517
llvm-svn: 255674
It turns out that terminatepad gives little benefit over a cleanuppad
which calls the termination function. This is not sufficient to
implement fully generic filters but MSVC doesn't support them which
makes terminatepad a little over-designed.
Depends on D15478.
Differential Revision: http://reviews.llvm.org/D15479
llvm-svn: 255522
While we have successfully implemented a funclet-oriented EH scheme on
top of LLVM IR, our scheme has some notable deficiencies:
- catchendpad and cleanupendpad are necessary in the current design
but they are difficult to explain to others, even to seasoned LLVM
experts.
- catchendpad and cleanupendpad are optimization barriers. They cannot
be split and force all potentially throwing call-sites to be invokes.
This has a noticable effect on the quality of our code generation.
- catchpad, while similar in some aspects to invoke, is fairly awkward.
It is unsplittable, starts a funclet, and has control flow to other
funclets.
- The nesting relationship between funclets is currently a property of
control flow edges. Because of this, we are forced to carefully
analyze the flow graph to see if there might potentially exist illegal
nesting among funclets. While we have logic to clone funclets when
they are illegally nested, it would be nicer if we had a
representation which forbade them upfront.
Let's clean this up a bit by doing the following:
- Instead, make catchpad more like cleanuppad and landingpad: no control
flow, just a bunch of simple operands; catchpad would be splittable.
- Introduce catchswitch, a control flow instruction designed to model
the constraints of funclet oriented EH.
- Make funclet scoping explicit by having funclet instructions consume
the token produced by the funclet which contains them.
- Remove catchendpad and cleanupendpad. Their presence can be inferred
implicitly using coloring information.
N.B. The state numbering code for the CLR has been updated but the
veracity of it's output cannot be spoken for. An expert should take a
look to make sure the results are reasonable.
Reviewers: rnk, JosephTremoulet, andrew.w.kaylor
Differential Revision: http://reviews.llvm.org/D15139
llvm-svn: 255422
- This simplifies the CallSite class, arg_begin / arg_end are now
simple wrapper getters.
- In several places, we were creating CallSite instances solely to call
arg_begin and arg_end. With this change, that's no longer required.
llvm-svn: 255226
Continuing the work from last week to remove implicit ilist iterator
conversions. First related commit was probably r249767, with some more
motivation in r249925. This edition gets LLVMTransformUtils compiling
without the implicit conversions.
No functional change intended.
llvm-svn: 250142
