2471 Commits

Author SHA1 Message Date
Zachary Turner
579bef0ca2 Add support for writing through StreamInterface.
This adds method and tests for writing to a PDB stream.  With
this, even a PDB stream which is discontiguous can be treated
as a sequential stream of bytes for the purposes of writing.

Reviewed By: ruiu
Differential Revision: http://reviews.llvm.org/D21157

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272369 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-10 05:09:12 +00:00
Reid Kleckner
3d3aca2d97 [DebugInfo] Add calling convention support for DWARF and CodeView
Summary:
Now DISubroutineType has a 'cc' field which should be a DW_CC_ enum.  If
it is present and non-zero, the backend will emit it as a
DW_AT_calling_convention attribute. On the CodeView side, we translate
it to the appropriate enum for the LF_PROCEDURE record.

I added a new LLVM vendor specific enum to the list of DWARF calling
conventions. DWARF does not appear to attempt to standardize these, so I
assume it's OK to do this until we coordinate with GCC on how to emit
vectorcall convention functions.

Reviewers: dexonsmith, majnemer, aaboud, amccarth

Subscribers: mehdi_amini, llvm-commits

Differential Revision: http://reviews.llvm.org/D21114

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272197 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-08 20:34:29 +00:00
Zachary Turner
47b89fc720 [pdb] Fix build errors in PDB unit tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272174 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-08 17:32:25 +00:00
Saleem Abdulrasool
e169351252 Support: correct AArch64 TargetParser implementation
The architecture enumeration is shared across ARM and AArch64.  However, the
data is not.  The code incorrectly would index into the array using the
architecture index which was offset by the ARMv7 architecture enumeration.  We
do not have a marker for indicating the architectural family to which the
enumeration belongs so we cannot be clever about offsetting the index (at least
it is not immediately apparent to me).  Instead, fall back to the tried-and-true
method of slowly iterating the array (its not a large array, so the impact of
this is not too high).

Because of the incorrect indexing, if we were lucky, we would crash, but usually
we would return an invalid StringRef.  We did not have any tests for the AArch64
target parser previously;.  Extend the previous tests I had added for ARM to
cover AArch64 for ensuring that we return expected StringRefs.

Take the opportunity to change some iterator types to references.

This work is needed to support parsing `.arch name` directives in the AArch64
target asm parser.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272145 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-08 14:30:00 +00:00
Zachary Turner
ca5b485311 [pdb] Fix broken unit test compilation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272059 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-07 20:46:39 +00:00
Zachary Turner
babe1202e2 [yaml] Add a ScalarTraits for mapping endian aware types.
This allows mapping of any endian-aware type whose underlying
type (e.g. uint32_t) provides a ScalarTraits specialization.

Reviewed by: majnemer
Differential Revision: http://reviews.llvm.org/D21057

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272049 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-07 19:32:09 +00:00
Zachary Turner
804dc35d2d [pdb] Fix broken unit tests after r271982.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271983 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-07 05:32:48 +00:00
Peter Collingbourne
052c9ee80b Verifier: Simplify and fix issue where we were not verifying unmaterialized functions.
Arrange to call verify(Function &) on each function, followed by
verify(Module &), whether the verifier is being used from the pass or
from verifyModule(). As a side effect, this fixes an issue that caused
us not to call verify(Function &) on unmaterialized functions from
verifyModule().

Differential Revision: http://reviews.llvm.org/D21042

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271956 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-06 23:21:27 +00:00
Eli Friedman
87dbdbfb52 Fix deadlock in ThreadPool unittest.
(Yes, this only deadlocks on a computer with a single core; I'm using
a virtual machine.)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271855 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-05 21:15:46 +00:00
Taewook Oh
2c2ab512e8 Revert commit r271704, a patch that enables warnings for non-portable #include and #import paths (Corresponding clang patch has been reverted by r271761). Patches are reverted because they generate lots of unadressable warnings for windows and fail tests under ASAN.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271764 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-04 03:36:12 +00:00
Taewook Oh
033103449b In openFileForRead, attempt to fetch the actual name of the file on disk -- including case -- so that clang can later warn about non-portable #include and #import directives.
Differential Revision: http://reviews.llvm.org/D19842

Patch by Eric Niebler



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271704 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-03 18:38:39 +00:00
Ben Craig
531b69a01c Adding reserve and capacity methods to FoldingSet
http://reviews.llvm.org/D20930

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271669 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-03 13:54:48 +00:00
Ahmed Bougacha
408a761951 [ADT] Pass ArrayRef::slice size_t instead of unsigned.
Also fix slice wrappers drop_front and drop_back.
The unittests are pretty awkward, but do the job; alternatives
welcome!

..and yes, I do have ArrayRefs with more than 4 billion elements.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271546 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-02 17:26:03 +00:00
Dylan McKay
e4d291c532 Add tests to Support/MathExtras
In r271380, I added several functions to get the minimum/maximum values
of n-width integers.

This just adds tests for them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271505 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-02 09:00:53 +00:00
David Majnemer
81d9dfc70d [CodeView] Take the StreamRef::readBytes offset into account when validating
We only considered the length of the operation and the length of the
StreamRef without considered what it meant for the offset to be at a
non-zero position.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271496 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-02 06:21:44 +00:00
NAKAMURA Takumi
35ffaf1afa Rework r271439. I forgot to save the buffer for editing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271441 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 23:03:46 +00:00
NAKAMURA Takumi
d76edeb3ba MappedBlockStreamTest.cpp: Simplify array initializers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271439 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 22:59:06 +00:00
Geoff Berry
783607f8e8 [MemorySSA] Port to new pass manager
Add support for the new pass manager to MemorySSA pass.

Change MemorySSA to be computed eagerly upon construction.

Change MemorySSAWalker to be owned by the MemorySSA object that creates
it.

Reviewers: dberlin, george.burgess.iv

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19664

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271432 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 21:30:40 +00:00
Zachary Turner
3ca9979447 [pdb] silence warnings about moving from a temporary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271420 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 18:18:55 +00:00
David Majnemer
d5f9b7e57e [CodeView] Make sure StreamRef::readBytes doesn't read too much
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271418 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 18:13:06 +00:00
David Majnemer
2511caa18b [PDB] Silence sign comparison warnings in MappedBlockStreamTest
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271416 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 18:13:02 +00:00
NAKAMURA Takumi
cc0c9e0cf6 MappedBlockStreamTest.cpp: Appease msc18 to avoid initializer for std::vector.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271397 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 14:26:54 +00:00
Peter Collingbourne
d8d85ac3c9 IR: Allow multiple global metadata attachments with the same type.
This will be necessary to allow the global merge pass to attach
multiple debug info metadata nodes to global variables once we reverse
the edge from DIGlobalVariable to GlobalVariable.

Differential Revision: http://reviews.llvm.org/D20414

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271358 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 01:17:57 +00:00
NAKAMURA Takumi
249a797178 DebugInfoPDBTests: Update libdeps for r271346.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271355 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-01 00:30:15 +00:00
Lang Hames
1fa1983597 [Orc] Add conversion to/from RuntimeDyld::SymbolInfo for JITSymbol.
This tidies up some code that was manually constructing RuntimeDyld::SymbolInfo
instances from JITSymbols. It will save more mess in the future when
JITSymbol::getAddress is extended to return an Expected<TargetAddress> rather
than just a TargetAddress, since we'll be able to embed the error checking in
the conversion.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271350 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-31 23:14:26 +00:00
Zachary Turner
e781066bc2 [pdb] Add unit tests for PDB MappedBlockStream and zero copy
Differential Revision: http://reviews.llvm.org/D20837
Reviewed By: ruiu

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271346 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-31 22:41:52 +00:00
Lang Hames
c93d4ea0e3 [Support] Rename unconvertibleErrorCode to inconvertibleErrorCode.
Based on a totally scientific, 30 second google search "in-" appears to be the
preferred prefix.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270950 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-27 01:54:25 +00:00
Lang Hames
5083fc5573 [Support] Add a StringError convenience class to Error.h
StringError can be used to represent Errors that aren't recoverable based on
the error type, but that have a useful error message that can be reported to
the user or logged.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270948 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-27 01:37:32 +00:00
Pete Cooper
18a6f17098 Don't allocate in APInt::slt. NFC.
APInt::slt was copying the LHS and RHS in to temporaries then making
them unsigned so that it could use an unsigned comparision.  It did
this even on the paths which were trivial to give results for, such
as the sign bit of the LHS being set while RHS was not set.

This changes the logic to return out immediately in the trivial cases,
and use an unsigned comparison in the remaining cases.  But this time,
just use the unsigned comparison directly without creating any temporaries.

This works because, for example:
  true = (-2 slt -1) = (0xFE ult 0xFF)

Also added some tests explicitly for slt with APInt's larger than 64-bits
so that this new code is tested.

Using the memory for 'opt -O2 verify-uselistorder.lto.opt.bc -o opt.bc'
(see r236629 for details), this reduces the number of allocations from
26.8M to 23.9M.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270881 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-26 17:40:07 +00:00
Adrian Prantl
b28eca74ff Port the strip-invalid-debuginfo logic to the legacy verifier pass, too.
Since r268966 the modern Verifier pass defaults to stripping invalid debug info
in nonasserts builds.  This patch ports this behavior back to the legacy
Verifier pass as well.  The primary motivation is that the clang frontend
accepts bitcode files as input but is still using the legacy pass pipeline.

Background: The problem I'm trying to solve with this sequence of patches is
that historically we've done a really bad job at verifying debug info. We want
to be able to make the verifier stricter without having to worry about breaking
bitcode compatibility with existing producers. For example, we don't necessarily
want IR produced by an older version of clang to be rejected by an LTO link just
because of malformed debug info, and rather provide an option to strip it. Note
that merely outdated (but well-formed) debug info would continue to be
auto-upgraded in this scenario.

http://reviews.llvm.org/D20629
<rdar://problem/26448800>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270768 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-25 21:33:20 +00:00
Matthias Braun
6063d9d32c LiveIntervalAnalysis: Fix handleMove() re-using the wrong value number
This fixes http://llvm.org/PR27856

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270619 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-24 21:54:01 +00:00
Matt Arsenault
bca8aba44a Fix constant folding of addrspacecast of null
This should not be making assumptions on the value of
the casted pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270293 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-21 00:14:04 +00:00
Easwaran Raman
30c760d801 Remove specializations of ProfileSummary
This removes the subclasses of ProfileSummary, moves the members of the derived classes to the base class.

Differential Revision: http://reviews.llvm.org/D20390



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270143 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-19 21:53:28 +00:00
Vedant Kumar
c77570e062 Retry^3 "[ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC"
Transition InstrProf and Coverage over to the stricter Error/Expected
interface.

Changes since the initial commit:
- Fix error message printing in llvm-profdata.
- Check errors in loadTestingFormat() + annotateAllFunctions().
- Defer error handling in InstrProfIterator to InstrProfReader.
- Remove the base ProfError class to work around an MSVC ICE.

Differential Revision: http://reviews.llvm.org/D19901

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270020 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-19 03:54:45 +00:00
Sanjoy Das
15c62f945a [ConstantRange] Add an getEquivalentICmp helper
Currently only its unit test uses it, but this will be used in a later
change to simplify some logic in the GuardWidening pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270018 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-19 03:53:06 +00:00
Rafael Espindola
ac8db59598 Delete Reloc::Default.
Having an enum member named Default is quite confusing: Is it distinct
from the others?

This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269988 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-18 22:04:49 +00:00
Rafael Espindola
bbc289f36c Delete dead code. Reloc::Default is the default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269954 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-18 16:19:20 +00:00
Teresa Johnson
a486381660 [ThinLTO] Option to control path of distributed backend files
Summary:
Add support to control where files for a distributed backend (the
individual index files and optional imports files) are created.

This is invoked with a new thinlto-prefix-replace option in the gold
plugin and llvm-lto. If specified, expects a string of the form
"oldprefix:newprefix", and instead of generating these files in the
same directory path as the corresponding bitcode file, will use a path
formed by replacing the bitcode file's path prefix matching oldprefix
with newprefix.

Also add a new replace_path_prefix helper to Path.h in libSupport.

Depends on D19636.

Reviewers: joker.eph

Subscribers: llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D19644

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269771 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-17 14:45:30 +00:00
Vedant Kumar
ce4aff93aa Revert "Retry^2 "[ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC""
This reverts commit r269694. MSVC says:

error C2086: 'char llvm::ProfErrorInfoBase<enum llvm::instrprof_error>::ID' : redefinition

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269700 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-16 21:03:38 +00:00
Vedant Kumar
515ee3e025 Retry^2 "[ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC"
Transition InstrProf and Coverage over to the stricter Error/Expected
interface.

Changes since the initial commit:
- Address undefined-var-template warning.
- Fix error message printing in llvm-profdata.
- Check errors in loadTestingFormat() + annotateAllFunctions().
- Defer error handling in InstrProfIterator to InstrProfReader.

Differential Revision: http://reviews.llvm.org/D19901

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269694 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-16 20:49:39 +00:00
Chandler Carruth
2e531af53a Revert "Retry "[ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC""
This reverts commit r269491. It triggers warnings with Clang, breaking
builds for -Werror users including several build bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269547 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-14 05:26:26 +00:00
Vedant Kumar
db1d476217 Retry "[ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC"
Transition InstrProf and Coverage over to the stricter Error/Expected
interface.

Changes since the initial commit:
- Fix error message printing in llvm-profdata.
- Check errors in loadTestingFormat() + annotateAllFunctions().
- Defer error handling in InstrProfIterator to InstrProfReader.

Differential Revision: http://reviews.llvm.org/D19901

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269491 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 21:50:56 +00:00
Bruno Cardoso Lopes
68857a7be9 [Support][Unittests] Add unittest for recursive_directory_iterator::level()
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269488 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 21:31:32 +00:00
Michael Zolotukhin
2463a66c88 Revert "Revert "[Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the...""
This reverts commit r269395.

Try to reapply with a fix from chapuni.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269486 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 21:23:25 +00:00
Vedant Kumar
8007bdd41f Revert "(HEAD -> master, origin/master, origin/HEAD) [ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC"
This reverts commit r269462. It fails two llvm-profdata tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269466 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 20:09:39 +00:00
Vedant Kumar
5b34ed8191 [ProfileData] (llvm) Use Error in InstrProf and Coverage, NFC
Transition InstrProf and Coverage over to the stricter Error/Expected
interface.

Differential Revision: http://reviews.llvm.org/D19901

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269462 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 20:01:27 +00:00
Michael Zolotukhin
a934d5cb93 Revert "[Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the..."
This reverts commit r269388.

It caused some bots to fail, I'm reverting it until I investigate the
issue.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269395 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 06:32:25 +00:00
Chandler Carruth
b29c2901de [ADT] Add an 'llvm::seq' function which produces an iterator range over
a sequence of values.

It increments through the values in the half-open range: [Begin, End),
producing those values when indirecting the iterator. It should support
integers, iterators, and any other type providing these basic arithmetic
operations.

This came up in the C++ standards committee meeting, and it seemed like
a useful construct that LLVM might want as well, and I wanted to
understand how easily we could solve it. I suspect this can be used to
write simpler counting loops even in LLVM along the lines of:

  for (int i : seq(0, v.size())) {
    ...
  };

As part of this, I had to fix the lack of a proxy object returned from
the operator[] in our iterator facade.

Differential Revision: http://reviews.llvm.org/D17870

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269390 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 03:57:50 +00:00
Michael Zolotukhin
a538be3ab1 [Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the...
Summary:
...loop after the last iteration.

This is really hard to do correctly. The core problem is that we need to
model liveness through the induction PHIs from iteration to iteration in
order to get the correct results, and we need to correctly de-duplicate
the common subgraphs of instructions feeding some subset of the
induction PHIs. All of this can be driven either from a side effect at
some iteration or from the loop values used after the loop finishes.

This patch implements this by storing the forward-propagating analysis
of each instruction in a cache to recall whether it was free and whether
it has become live and thus counted toward the total unroll cost. Then,
at each sink for a value in the loop, we recursively walk back through
every value that feeds the sink, including looping back through the
iterations as needed, until we have marked the entire input graph as
live. Because we cache this, we never visit instructions more than twice
-- once when we analyze them and put them into the cache, and once when
we count their cost towards the unrolled loop. Also, because the cache
is only two bits and because we are dealing with relatively small
iteration counts, we can store all of this very densely in memory to
avoid this from becoming an excessively slow analysis.

The code here is still pretty gross. I would appreciate suggestions
about better ways to factor or split this up, I've stared too long at
the algorithmic side to really have a good sense of what the design
should probably look at.

Also, it might seem like we should do all of this bottom-up, but I think
that is a red herring. Specifically, the simplification power is *much*
greater working top-down. We can forward propagate very effectively,
even across strange and interesting recurrances around the backedge.
Because we use data to propagate, this doesn't cause a state space
explosion. Doing this level of constant folding, etc, would be very
expensive to do bottom-up because it wouldn't be until the last moment
that you could collapse everything. The current solution is essentially
a top-down simplification with a bottom-up cost accounting which seems
to get the best of both worlds. It makes the simplification incremental
and powerful while leaving everything dead until we *know* it is needed.

Finally, a core property of this approach is its *monotonicity*. At all
times, the current UnrolledCost is a conservatively low estimate. This
ensures that we will never early-exit from the analysis due to exceeding
a threshold when if we had continued, the cost would have gone back
below the threshold. These kinds of bugs can cause incredibly hard to
track down random changes to behavior.

We could use a techinque similar (but much simpler) within the inliner
as well to avoid considering speculated code in the inline cost.

Reviewers: chandlerc

Subscribers: sanjoy, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D11758

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269388 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 01:42:39 +00:00
Xinliang David Li
a4cc7ae52a Remove runtime specific code from common header
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269384 91177308-0d34-0410-b5e6-96231b3b80d8
2016-05-13 00:23:49 +00:00