351 Commits

Author SHA1 Message Date
Chad Rosier
c0a787d682 [InstCombine] Catch more bswap cases missed due to zext and truncs.
Fixes PR27824.
Differential Revision: http://reviews.llvm.org/D20591.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270853 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-26 14:58:51 +00:00
Chad Rosier
b744845677 Clarify that we match BSwap in InstCombine and BitReverse in CGP. NFC.
Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270715 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-25 16:22:14 +00:00
Chad Rosier
7143168577 Fix 80-column violation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270329 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-21 21:12:06 +00:00
Reid Kleckner
0e77da267e Revert "[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics"
This reverts commit r268254.

This change causes assertion failures while building Chromium. Reduced
test case coming soon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268288 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-02 19:43:22 +00:00
Hans Wennborg
0c15a0b738 [SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268254 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-02 17:22:54 +00:00
Sanjoy Das
3aa5468391 Mark guards on true as "trivially dead"
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268126 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-29 22:23:16 +00:00
Hal Finkel
1ccb72c441 [SimplifyCFG] Preserve !llvm.mem.parallel_loop_access when merging
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267515 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-26 02:06:06 +00:00
Sanjoy Das
84a84a1723 [SimplifyCFG] Fold llvm.guard(false) to unreachable
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266955 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-21 05:09:12 +00:00
Sanjoy Das
4f285499ea [RS4GC] Lower calls to @llvm.experimental.deoptimize
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264456 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-25 20:12:13 +00:00
Duncan P. N. Exon Smith
8de6150816 ADT: Remove == and != comparisons between ilist iterators and pointers
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261498 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-21 20:39:50 +00:00
Adrian Prantl
465522b1fa Debug Info: Teach LdStHasDebugValue() (Local.cpp) about DIExpressions.
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>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261145 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-17 20:02:25 +00:00
Matthias Braun
5e08bd340a Avoid overly large SmallPtrSet/SmallSet
These sets perform linear searching in small mode so it is never a good
idea to use SmallSize/N bigger than 32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259283 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-30 01:24:31 +00:00
David Majnemer
2f0346603d [SCCP] Remove duplicate code
SCCP has code identical to changeToUnreachable's behavior, switch it
over to just call changeToUnreachable.

No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258654 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-24 06:26:47 +00:00
David Majnemer
6b7f46e721 [InstCombine, SCCP] Consolidate code used to remove instructions
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258653 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-24 05:26:18 +00:00
David L Kreitzer
fad7d1588f Fix for two constant propagation problems in GVN with the assume intrinsic
instruction.

Patch by Yuanrui Zhang.

Differential Revision: http://reviews.llvm.org/D16100


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258435 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-21 21:32:35 +00:00
James Y Knight
b707e2a85c Stop increasing alignment of externally-visible globals on ELF
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257902 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-15 16:33:06 +00:00
James Molloy
cd54bb4874 [InstCombine] Rewrite bswap/bitreverse handling completely.
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257875 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-15 09:20:19 +00:00
Keno Fischer
4d6ccf4c99 [Utils] Fix incorrect dbg.declare store conversion
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257787 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-14 19:12:27 +00:00
James Y Knight
ee7d060ab8 Revert "Stop increasing alignment of externally-visible globals on ELF platforms."
This reverts commit r257719, due to PR26144.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257775 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-14 16:33:21 +00:00
James Y Knight
326b7ceee0 Stop increasing alignment of externally-visible globals on ELF
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257719 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-13 23:59:19 +00:00
Keno Fischer
58b254770a [Utils] Insert DW_OP_bit_piece when only describing part of the variable
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257534 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-12 22:46:09 +00:00
David Majnemer
0b06a2d608 [JumpThreading] Don't forget to report that the IR changed
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257279 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-10 07:13:04 +00:00
Manuel Jacob
7b845c18db [Statepoints] Check for the "gc-leaf-function" attribute on call sites as well.
Reviewers: sanjoy, reames

Subscribers: sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D15900

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256875 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-05 23:59:08 +00:00
David Majnemer
a3d4e67e43 [SimplifyCFG] Further improve our ability to remove redundant catchpads
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256815 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-05 07:42:17 +00:00
David Majnemer
a4824774dc [SimplifyCFG] Remove redundant catchpads
Remove duplicate catchpad handlers from a catchswitch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256814 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-05 06:27:50 +00:00
Keno Fischer
bae9026417 Clean up the processing of dbg.value in various places
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256077 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-19 02:02:44 +00:00
David Majnemer
b46bb541f5 [WinEH] Use operand bundles to describe call sites
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255674 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-15 21:27:27 +00:00
David Majnemer
868145efb0 [IR] Remove terminatepad
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255522 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-14 18:34:23 +00:00
David Majnemer
8cec2f2816 [IR] Reformulate LLVM's EH funclet IR
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255422 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-12 05:38:55 +00:00
Sanjoy Das
fd947f33ba Add arg_begin() and arg_end() to CallInst and InvokeInst; NFCI
- 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255226 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-10 06:39:02 +00:00
Sanjoy Das
12ab14b2f8 [OperandBundles] Fix a transform in simplifycfg
Reviewers: pcc, majnemer, reames

Subscribers: reames, llvm-commits

Differential Revision: http://reviews.llvm.org/D15345

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255062 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-08 22:26:08 +00:00
David Majnemer
1114aa2fc6 Move EH-specific helper functions to a more appropriate place
No functionality change is intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254562 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-02 23:06:39 +00:00
Evgeniy Stepanov
dd121fc847 [safestack] Protect byval function arguments.
Detect unsafe byval function arguments and move them to the unsafe
stack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254353 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-01 00:40:05 +00:00
Artur Pilipenko
bf7f89f132 Preserve load alignment and dereferenceable metadata during some transformations
Reviewed By: hfinkel

Differential Revision: http://reviews.llvm.org/D13953


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251809 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-02 17:53:51 +00:00
Duncan P. N. Exon Smith
5270f8871a TransformUtils: Remove implicit ilist iterator conversions, NFC
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250142 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-13 02:39:05 +00:00
Sanjoy Das
b18f03aba5 [PlaceSafeopints] Extract out callsGCLeafFunction, NFC
Summary:
This will be used in a later change to RewriteStatepointsForGC.

Reviewers: reames, swaroop.sridhar

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13490

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249777 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-08 23:18:30 +00:00
Piotr Padlewski
264b0361be inariant.group handling in GVN
The most important part required to make clang
devirtualization works ( ͡°͜ʖ ͡°).
The code is able to find non local dependencies, but unfortunatelly
because the caller can only handle local dependencies, I had to add
some restrictions to look for dependencies only in the same BB.

http://reviews.llvm.org/D12992

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249196 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-02 22:12:22 +00:00
Evgeniy Stepanov
1eca697107 Fix debug info with SafeStack.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248933 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-30 19:55:43 +00:00
Evgeniy Stepanov
e0bc463811 Move dbg.declare intrinsics when merging and replacing allocas.
Place new and update dbg.declare calls immediately after the
corresponding alloca.

Current code in replaceDbgDeclareForAlloca puts the new dbg.declare
at the end of the basic block. LLVM codegen has problems emitting
debug info in a situation when dbg.declare appears after all uses of
the variable. This usually kinda works for inlining and ASan (two
users of this function) but not for SafeStack (see the pending change
in http://reviews.llvm.org/D13178).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248769 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-29 00:30:19 +00:00
Fiona Glaser
c4a5a9a48e Improve performance of SimplifyInstructionsInBlock
1. Use a worklist, not a recursive approach, to avoid needless
   revisitation and being repeatedly forced to jump back to the
   start of the BB if a handle is invalidated.

2. Only insert operands to the worklist if they become unused
   after a dead instruction is removed, so we don’t have to
   visit them again in most cases.

3. Use a SmallSetVector to track the worklist.

4. Instead of pre-initting the SmallSetVector like in
   DeadCodeEliminationPass, only put things into the worklist
   if they have to be revisited after the first run-through.
   This minimizes how much the actual SmallSetVector gets used,
   which saves a lot of time.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248727 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-28 18:56:07 +00:00
Joseph Tremoulet
8a43b3fad9 [EH] Create removeUnwindEdge utility
Summary:
Factor the code that rewrites invokes to calls and rewrites WinEH
terminators to their "unwind to caller" equivalents into a helper in
Utils/Local, and use it in the three places I'm aware of that need to do
this.


Reviewers: andrew.w.kaylor, majnemer, rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13152

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248677 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-27 01:47:46 +00:00
Piotr Padlewski
782ac282c5 Constant propagation after hitting assume(cmp) bugfix
Last time code run into assertion `BBE.isSingleEdge()` in
lib/IR/Dominators.cpp:200.

http://reviews.llvm.org/D12170

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246696 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-02 19:59:59 +00:00
Benjamin Kramer
7c393ccd97 [RemoveDuplicatePHINodes] Start over after removing a PHI.
This makes RemoveDuplicatePHINodes more effective and fixes an assertion
failure. Triggering the assertions requires a DenseSet reallocation
so this change only contains a constructive test.

I'll explain the issue with a small example. In the following function
there's a duplicate PHI, %4 and %5 are identical. When this is found
the DenseSet in RemoveDuplicatePHINodes contains %2, %3 and %4.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %5, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  %5 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

after RemoveDuplicatePHINodes runs the function looks like this. %3 has
changed and is now identical to %2, but RemoveDuplicatePHINodes never
saw this.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

If the DenseSet does a reallocation now it will reinsert all
keys and stumble over %3 now having a different hash value than it had
when inserted into the map for the first time. This change clears the
set whenever a PHI is deleted and starts the progress from the
beginning, allowing %3 to be deleted and avoiding inconsistent DenseSet
state. This potentially has a negative performance impact because
it rescans all PHIs, but I don't think that this ever makes a difference
in practice.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246694 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-02 19:52:23 +00:00
Steven Wu
109cab4450 Revert r246244 and r246243
These two commits cause clang/llvm bootstrap to hang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246279 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-28 06:52:00 +00:00
Piotr Padlewski
bcd94e99ee Constant propagation after hitting assume(cmp) bugfix
Last time code run into assertion `BBE.isSingleEdge()` in
lib/IR/Dominators.cpp:200.

http://reviews.llvm.org/D12170

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246244 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-28 01:02:00 +00:00
Adrian Prantl
178fbb3654 Rename Instruction::dropUnknownMetadata() to dropUnknownNonDebugMetadata()
and make it always preserve debug locations, since all callers wanted this
behavior anyway.

This is addressing a post-commit review feedback for r245589.

NFC (inside the LLVM tree).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245622 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 22:00:30 +00:00
Chen Li
b3df24519c [ConstantFoldTerminator] Preserve make.implicit metadata when converting SwitchInst to BranchInst
Summary: llvm::ConstantFoldTerminator function can convert SwitchInst with single case (and default) to a conditional BranchInst. This patch adds support to preserve make.implicit metadata on this conversion.

Reviewers: sanjoy, weimingz, chenli

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D11841

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244348 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-07 19:30:12 +00:00
Pete Cooper
be21eab7ac Convert a bunch of loops to foreach. NFC.
After r244074, we now have a successors() method to iterate over
all the successors of a TerminatorInst.  This commit changes a bunch
of eligible loops to use it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244260 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-06 20:22:46 +00:00
David Majnemer
4a45f0871a New EH representation for MSVC compatibility
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Differential Revision: http://reviews.llvm.org/D11097

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243766 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 17:58:14 +00:00
Reid Kleckner
b53f724f91 Update enforceKnownAlignment after the isWeakForLinker semantic change
Previously we would refrain from attempting to increase the linkage of
available_externally globals because they were considered weak for the
linker. Now they are treated more like a declaration instead of a weak
definition.

This was causing SSE alignment faults in Chromuim, when some code
assumed it could increase the alignment of a dllimported global that it
didn't control.  http://crbug.com/509256

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242091 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-14 00:11:08 +00:00