In SimplifyCFG when given a conditional branch that goes to BB1 and BB2, the hoisted common terminator instruction in the two blocks, caused debug line records associated with subsequent select instructions to become ambiguous. It causes the debugger to display unreachable source lines.
Differential Revision: https://reviews.llvm.org/D53390
llvm-svn: 346481
When SimplifyCFG changes the PHI node into a select instruction, the debug line records becomes ambiguous. It causes the debugger to display unreachable source lines.
Differential Revision: https://reviews.llvm.org/D53287
llvm-svn: 345250
by `getTerminator()` calls instead be declared as `Instruction`.
This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).
llvm-svn: 344502
When SimplifyCFG changes the PHI node into a select instruction, the debug line records becomes ambiguous. It causes the debugger to display unreachable source lines.
Differential Revision: https://reviews.llvm.org/D52887
llvm-svn: 344120
Summary:
At some point in the past the recursion in DominatesMergePoint used to pass null for AggressiveInsts as part of the recursion. It no longer does this. So there is no way for AggressiveInsts to be null.
This passes it by reference and removes the null check to make this explicit.
Reviewers: efriedma, reames
Reviewed By: efriedma
Subscribers: xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D52575
llvm-svn: 343828
Summary:
The llvm::SimplifyCFG function creates a SimplifyCFGOpt object and calls run on it. There were numerous places reached from this run function that called back out llvm::SimplifyCFG which would create another SimplifyCFGOpt object. This is an inefficient use of stack space at minimum. We are also not passing along the LoopHeaders pointer passed into the outer llvm::SimplifyCFG call. So if its not null we lose it on the first recursion and get nullptr from there on.
This patch adds an outer loop around the main BasicBlock simplifying code and adds a flag to the SimplifyCFGOpt class that can be set by to request another iteration. I don't think we can iterate based just on the change flag alone since some of the simplifications delete a basic block entirely leaving nothing to iterate on.
Reviewers: bogner, eli.friedman, reames
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52760
llvm-svn: 343816
getNumUses is linear in the number of uses. Since we're looking for a specific use count, we can use hasNUses which will stop as soon as it determines there are more than N uses instead of walking all of them.
llvm-svn: 343550
When SimplifyCFG changes the PHI node into a select instruction, the debug information becomes ambiguous. It causes the debugger to display wrong variable value.
Differential Revision: https://reviews.llvm.org/D51976
llvm-svn: 342527
Previously the alignment on the newly created switch table data was not set,
meaning that DataLayout::getPreferredAlignment was free to overalign it to 16
bytes. This causes unnecessary code bloat.
Differential Revision: https://reviews.llvm.org/D51800
llvm-svn: 342039
This reverts commit r340997.
This change turned out not to be NFC after all, but e.g. causes
clang to crash when building the linux kernel for aarch64.
llvm-svn: 341031
The cost modeling was not accounting for the fact we were duplicating the instruction once per predecessor. With a default threshold of 1, this meant we were actually creating #pred copies.
Adding to the fun, there is *absolutely no* test coverage for this. Simply bailing for more than one predecessor passes all checked in tests.
llvm-svn: 341001
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.
All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.
llvm-svn: 340701
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.
Part of removing `TerminatorInst` from the `Instruction` type hierarchy
to make it easier to share logic and interfaces between instructions
that are both terminators and not terminators.
llvm-svn: 340699
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.
The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.
Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.
This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html
There will be a series of much more mechanical changes following this
one to complete this move.
Differential Revision: https://reviews.llvm.org/D47467
llvm-svn: 340698
This patch makes the DoesKMove argument non-optional, to force people
to think about it. Most cases where it is false are either code hoisting
or code sinking, where we pick one instruction from a set of
equal instructions among different code paths.
Reviewers: dberlin, nlopes, efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D47475
llvm-svn: 340606
Summary:
Previously, `eraseFromParent()` calls `delete` which invalidates the value of the pointer. Copying the value of the pointer later is undefined behavior in C++11 and implementation-defined (which may cause a segfault on implementations having strict pointer safety) in C++14.
This patch removes the BasicBlock pointer from related SmallPtrSet before `delete` invalidates it in the SimplifyCFG pass.
Reviewers: kuhar, dmgreen, davide, trentxintong
Reviewed By: kuhar, dmgreen
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50717
llvm-svn: 339773
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.
More details : https://lkml.org/lkml/2018/4/4/601
GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.
-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.
This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.
Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv
Reviewed By: efriedma, george.burgess.iv
Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D47895
llvm-svn: 336613
Currently SmallSet<PointerTy> inherits from SmallPtrSet<PointerTy>. This
patch replaces such types with SmallPtrSet, because IMO it is slightly
clearer and allows us to get rid of unnecessarily including SmallSet.h
Reviewers: dblaikie, craig.topper
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D47836
llvm-svn: 334492
SmallSet forwards to SmallPtrSet for pointer types. SmallPtrSet supports iteration, but a normal SmallSet doesn't. So if it wasn't for the forwarding, this wouldn't work.
These places were found by hiding the begin/end methods in the SmallSet forwarding
llvm-svn: 334343
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
Summary:
Fix a case where FoldBranchToCommonDest() would bail out from doing CSE
when encountering a debug intrinsic. Handle that by skipping past the
debug intrinsics.
Also, as a minor refactoring, rename checkCSEInPredecessor() to
tryCSEWithPredecessor() to make it a bit more clear that the function
may remove instructions.
Reviewers: fhahn, craig.topper, dblaikie, xbolva00
Reviewed By: fhahn, xbolva00
Subscribers: vsk, davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D46635
llvm-svn: 332698
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
This commit adds a wrapper for std::distance() which works with ranges.
As it would be a common case to write `distance(predecessors(BB))`, this
also introduces `pred_size()` and `succ_size()` helpers to make that
easier to write.
Differential Revision: https://reviews.llvm.org/D46668
llvm-svn: 332057
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
This patch updates some code responsible the skip debug info to use
BasicBlock::instructionsWithoutDebug. I think this makes things slightly
simpler and more direct.
Reviewers: aprantl, vsk, hans, danielcdh
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D46252
llvm-svn: 331221
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.
Reviewers: kcc, pcc, danielcdh, jmolloy, sanjoy, dberlin, ruiu
Reviewed By: ruiu
Subscribers: ruiu, llvm-commits
Differential Revision: https://reviews.llvm.org/D45142
llvm-svn: 330059
Summary:
Currently merge conditional stores can't handle cases where PostBB (the block we need to move the store to) has more than 2 predecessors.
This patch removes that restriction by creating a new block with only the 2 predecessors we care about and an unconditional branch to the original block. This provides a place to put the store.
Reviewers: efriedma, jmolloy, ABataev
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39760
llvm-svn: 329142
Summary:
When building with libFuzzer, converting control flow to selects or
obscuring the original operands of CMPs reduces the effectiveness of
libFuzzer's heuristics.
This patch provides an attribute to disable or modify certain optimizations
for optimal fuzzing signal.
Provides a less aggressive alternative to https://reviews.llvm.org/D44057.
Reviewers: vitalybuka, davide, arsenm, hfinkel
Reviewed By: vitalybuka
Subscribers: junbuml, mehdi_amini, wdng, javed.absar, hiraditya, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D44232
llvm-svn: 328214
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
When hoisting common code from the "then" and "else" branches of a condition
to before the "if", the HoistThenElseCodeToIf routine will attempt to merge
the debug location associated with the two original copies of the hoisted
instruction.
This is a problem in the special case where the hoisted instruction is a
debug info intrinsic, since for those the debug location is considered
part of the intrinsic and attempting to modify it may resut in invalid
IR. This is the underlying cause of PR36410.
This patch fixes the problem by handling debug info intrinsics specially:
instead of hoisting one copy and merging the two locations, the code now
simply hoists both copies, each with its original location intact. Note
that this is still only done in the case where both original copies are
otherwise (i.e. apart from location metadata) identical.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D44312
llvm-svn: 327622
When hoisting common code from the "then" and "else" branches of a condition
to before the "if", there is no need to require that debug intrinsics match
before moving them (and merging them). Instead, we can simply always keep
all debug intrinsics from both sides of the "if".
This fixes PR36410, which describes a problem where as a result of the attempt
to merge debug locations for two debug intrinsics we end up with an invalid
intrinsic, where the scope indicated in the !dbg location no longer matches
the scope of the variable tracked by the intrinsic.
In addition, this has the benefit that we no longer throw away information
that is actually still valid, helping to generate better debug data.
Reviewed By: vsk
Differential Revision: https://reviews.llvm.org/D44312
llvm-svn: 327175
The commit rL308422 introduces a restriction for folding unconditional
branches. Specifically if empty block with unconditional branch leads to
header of the loop then elimination of this basic block is prohibited.
However it seems this condition is redundantly strict.
If elimination of this basic block does not introduce more back edges
then we can eliminate this block.
The patch implements this relax of restriction.
The test profile/Linux/counter_promo_nest.c in compiler-rt project
is updated to meet this change.
Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl
Reviewed By: pacxx
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42691
llvm-svn: 324572
The patch causes the failure of the test
compiler-rt/test/profile/Linux/counter_promo_nest.c
To unblock buildbot, revert the patch while investigation is in progress.
Differential Revision: https://reviews.llvm.org/D42691
llvm-svn: 324214
The commit rL308422 introduces a restriction for folding unconditional
branches. Specifically if empty block with unconditional branch leads to
header of the loop then elimination of this basic block is prohibited.
However it seems this condition is redundantly strict.
If elimination of this basic block does not introduce more back edges
then we can eliminate this block.
The patch implements this relax of restriction.
Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl
Reviewed By: pacxx
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42691
llvm-svn: 324208
The function can take a significant amount of time on some
complicated test cases, but for the currently only use of
the function we can stop the initialization much earlier
when we find out we are going to discard the result anyway
in the caller of the function.
Adding configurable cut-off points so that we avoid wasting time.
NFCI.
llvm-svn: 322248
