Commit Graph

103468 Commits

Author SHA1 Message Date
Richard Smith
c51c340989 [modules] Add missing #include.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208276 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-08 02:34:32 +00:00
Saleem Abdulrasool
f6efab64b4 test: fix silly typo
Oh silly Darwin and your case insensitive file system.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208274 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-08 01:41:04 +00:00
Saleem Abdulrasool
dade1d5db5 ARM: support FK_SecRel_2 relocations on WoA
This adds FK_SecRel_2 relocation support to ARM.  This enables the building of
object files for armv7-windows-msvc which enables CodeView line tables for
debugging as opposed to armv7-windows-itanium which currently uses DWARF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208273 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-08 01:35:57 +00:00
Richard Smith
4983b992ab Simplify and fix incorrect comment. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208272 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-08 01:08:43 +00:00
Filipe Cabecinhas
b19c087aa7 Lower certain build_vectors to insertps instructions
Summary:
Vectors built with zeros and elements in the same order as another
(source) vector are optimized to be built using a single insertps
instruction.
Also optimize when we move one element in a vector to a different place
in that vector while zeroing out some of the other elements.

Further optimizations are possible, described in TODO comments.
I will be implementing at least some of them in the near future.

Added some tests for different cases where this optimization triggers.

Reviewers: nadav, delena, craig.topper

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D3521

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208271 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-08 00:25:16 +00:00
Lang Hames
52298507e8 Back out r208257 while I investigate tester failures.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208267 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 23:35:53 +00:00
Duncan P. N. Exon Smith
04d60023af GlobalValue: Assert symbols with local linkage have default visibility
The change to ExtractGV.cpp has no functionality change except to avoid
the asserts.  Existing testcases already cover this, so I didn't add a
new one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208264 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 23:00:22 +00:00
Duncan P. N. Exon Smith
76c17d324c IR: Don't allow non-default visibility on local linkage
Visibilities of `hidden` and `protected` are meaningless for symbols
with local linkage.

  - Change the assembler to reject non-default visibility on symbols
    with local linkage.

  - Change the bitcode reader to auto-upgrade `hidden` and `protected`
    to `default` when the linkage is local.

  - Update LangRef.

<rdar://problem/16141113>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208263 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:57:20 +00:00
Duncan P. N. Exon Smith
c7e175a743 LTO: Assert visibility of local linkage when merging symbols
`ModuleLinker::getLinkageResult()` shouldn't create symbols with local
linkage and non-default visibility -- in fact, symbols with local
linkage shouldn't be merged at all.  Assert to that effect.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208262 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:55:46 +00:00
Duncan P. N. Exon Smith
83533dd617 LTO: Check local linkage first
Since visibility is meaningless for symbols with local linkage, check
local linkage before visibility when setting symbol attributes.

When linkage is `internal` and the visibility is `hidden`, the exposed
attribute is now `LTO_SYMBOL_SCOPE_INTERNAL` instead of
`LTO_SYMBOL_SCOPE_HIDDEN`.  Although the bitfield allows *both* to be
specified, the combination is nonsense anyway.

Given changes (in progress) to drop visibility when a symbol has local
linkage, this almost has no functionality change: it's mostly a cleanup
to clarify the logic.

The exception is when something has `appending` linkage.  Before this
change, such symbols would be advertised as `LTO_SYMBOL_SCOPE_INTERNAL`;
now, they'll be given `LTO_SYMBOL_SCOPE_COMMON`.

Unfortunately this is really awkward to test.  This only changes what we
advertise to linkers (before running LTO), not what the final object
looks like.  In theory I could add `DEBUG` output to `llvm-lto` (and
test with "REQUIRES: asserts"), but follow-up commits to disallow
`internal hidden` simplify this anyway.

<rdar://problem/16141113>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208261 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:53:14 +00:00
Quentin Colombet
57b4c5d473 [X86] Add a test case for r208252.
Prior to r208252, the FMA 231 family was marked as isCommutable. However the
memory variants of this family are not commutable. Therefore, we did not
implemented the findCommutedOpIndices for those variants and missed that
the default implementation (more or less: commute indices 1 and 2) was
firing behind our back.
As a result, as demonstrated in the test case before the fix, we were
transforming a = b * c + a into a = a * c + b.

I.e., before r208252 we were generating for this test case:
vmovaps %xmm0, %xmm1
vmoss (%rsi), %xmm0
vfmadd231ss (%rdi), %xmm1, %xmm0

Instead of:
vmoss (%rsi), %xmm1
vfmadd231ss (%rdi), %xmm1, %xmm0

<rdar://problem/16800495> 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208260 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:52:58 +00:00
Lang Hames
3186597423 [RuntimeDyld] Make RuntimeDyldImpl::resolveExternalSymbols preserve the
relocation entries it applies.

Prior to this patch, RuntimeDyldImpl::resolveExternalSymbols discarded
relocations for external symbols once they had been applied. This causes issues
if the client calls MCJIT::finalizeLoadedModules more than once, and updates the
location of any symbols in between (e.g. by calling MCJIT::mapSectionAddress).

No test case yet: None of our in-tree memory managers support moving sections
around. I'll have to hack up a dummy memory manager before I can write a unit
test.

Fixes <rdar://problem/16764378>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208257 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:34:08 +00:00
Hal Finkel
df60e43e05 [X86TTI] Remove the unrolling branch limits
The loop stream detector (LSD) on modern Intel cores, which optimizes the
execution of small loops, has limits on the number of taken branches in
addition to uop-count limits (modern AMD cores have similar limits).
Unfortunately, at the IR level, estimating the number of branches that will be
taken is difficult. For one thing, it strongly depends on later passes (block
placement, etc.). The original implementation took a conservative approach and
limited the maximal BB DFS depth of the loop.  However, fairly-extensive
benchmarking by several of us has revealed that this is the wrong approach. In
fact, there are zero known cases where the branch limit prevents a detrimental
unrolling (but plenty of cases where it does prevent beneficial unrolling).

While we could improve the current branch counting logic by incorporating
branch probabilities, this further complication seems unjustified without a
motivating regression. Instead, unless and until a regression appears, the
branch counting will be removed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208255 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:25:18 +00:00
Justin Bogner
f7659e715f llvm-cov: Fix some funny indentation (NFC)
Noticed by Duncan Exon Smith. Thanks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208253 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 21:50:43 +00:00
Quentin Colombet
97e15a8309 [X86] Selectively mark the FMA variants inside a family as isCommutable.
Given a FMA family (e.g., 213, 231), not all the variants (i.e., register or
memory) are commutable.
E.g., for the 213 family (with the syntax src1, src2, src3):
fmaXXX213 A, B, reg3/mem3 == fmaXXX213 B, A, reg3/mem3

Now consider the 231 family:
fmaXXX231 A, B, reg3 == fmaXXX231 A, reg3, B
But
fmaXXX231 A, B, mem3 != fmaXXX231 A, mem3, B
Indeed, mem3 cannot be the second argument of the memory variant of fmaXXX231.

Working on a reduced test case!

<rdar://problem/16800495>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208252 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 21:43:35 +00:00
Eric Christopher
db411a94d2 Reformat a couple of functions for clarity.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208248 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 21:05:47 +00:00
Nico Weber
1ec10c111c Let OnDiskHashTable call the destructor of its Items.
OnDiskHashTable::insert() calls the Item constructor via placement new, but
nothing called the destructor.  This matters in cases when the Info template
parameter has key_type or data_type typedefs that have a destructor, for
example like IdentifierIndexWriterTrait in clang's GlobalModuleIndex.cpp.

This fixes a 5-year old bug that's been around since the OnDiskHashTable code
was added in r64192.  Bug found by LSan!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208243 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 19:55:38 +00:00
Rafael Espindola
b507e6601d Replace a virtual with an override.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208242 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 19:52:32 +00:00
Jyotsna Verma
8b915bad69 [Hexagon] Add New TSFlags to be used in the upcoming patches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208239 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 19:07:34 +00:00
Sebastian Pop
4842e7db63 avoid segfaulting
*Quotient and *Remainder don't have to be initialized.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208238 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 19:00:37 +00:00
Sebastian Pop
bde4574fcb do not collect undef terms
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208237 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 19:00:32 +00:00
Matt Arsenault
ad4e6970a1 Fix using wrong result type for setcc.
When reducing the bitwidth of a comparison against a constant, the
original setcc's result type was used, which was incorrect.

No test since I don't think any other in tree targets change the
bitwidth of the setcc type depending on the bitwidth of the compared
type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208236 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 18:26:58 +00:00
Eric Christopher
bbad52193e Debug.h already includes raw_ostream.h, no need to include it again.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208235 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 18:19:04 +00:00
Adam Nemet
a822fab74d [Test] Remove c-index-test from the list of substitutions
All the tests are under the clang tests and none should be under llvm moving
forward.

The topic was discussed in this thread:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140428/214905.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208234 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 18:16:02 +00:00
Sebastian Pop
5026b2cc8b split delinearization pass in 3 steps
To compute the dimensions of the array in a unique way, we split the
delinearization analysis in three steps:

- find parametric terms in all memory access functions
- compute the array dimensions from the set of terms
- compute the delinearized access functions for each dimension

The first step is executed on all the memory access functions such that we
gather all the patterns in which an array is accessed. The second step reduces
all this information in a unique description of the sizes of the array. The
third step is delinearizing each memory access function following the common
description of the shape of the array computed in step 2.

This rewrite of the delinearization pass also solves a problem we had with the
previous implementation: because the previous algorithm was by induction on the
structure of the SCEV, it would not correctly recognize the shape of the array
when the memory access was not following the nesting of the loops: for example,
see polly/test/ScopInfo/multidim_only_ivs_3d_reverse.ll

; void foo(long n, long m, long o, double A[n][m][o]) {
;
;   for (long i = 0; i < n; i++)
;     for (long j = 0; j < m; j++)
;       for (long k = 0; k < o; k++)
;         A[i][k][j] = 1.0;

Starting with this patch we no longer delinearize access functions that do not
contain parameters, for example in test/Analysis/DependenceAnalysis/GCD.ll

;;  for (long int i = 0; i < 100; i++)
;;    for (long int j = 0; j < 100; j++) {
;;      A[2*i - 4*j] = i;
;;      *B++ = A[6*i + 8*j];

these accesses will not be delinearized as the upper bound of the loops are
constants, and their access functions do not contain SCEVUnknown parameters.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208232 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 18:01:20 +00:00
Chandler Carruth
905e33545c [x86] Make the 'x86-64' cpu, what I see as and many use as the generic
default architecture for reasonable modern x86 processors, actually be
modern. This processor model should essentially be "tuned" for modern
x86 chips as much as possible without undue penalties on any specific
architecture. Previously we weren't even using the nice scheduling
models. There are a few other tweaks needed here, but this change at
least I have benchmarked across a decent swatch of chips (intel's
clovertown, westmere, and sandybridge; amd's istanbul) and seen no
significant regressions.

If anyone has suggested ways to test this, just let me know. Somewhat
alarmingly, no existing tests failed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208230 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 17:37:03 +00:00
Chandler Carruth
40b514dc28 Tidy up whitespace with clang-format prior to making significant
changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208229 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 17:36:59 +00:00
Simon Atanasyan
d92c843b2e [yaml2obj] Support ELF x86 relocations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208228 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 17:06:38 +00:00
Rafael Espindola
4d88db0d81 Style update: don't duplicate the function name.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208227 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 17:04:45 +00:00
Alexey Samsonov
0f0974ddb9 [CMake] Add build rules for llvm-PerfectShuffle utility
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208225 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 16:54:00 +00:00
Rafael Espindola
3a163b7692 Style update: don't duplicate the function name.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208224 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 16:43:23 +00:00
Chad Rosier
8f0f458824 [ARM64][fast-isel] Disable target specific optimizations at -O0. Functionally,
this patch disables the dead register elimination pass and the load/store pair
optimization pass at -O0.  The ILP optimizations don't require the optimization
level to be checked because the call to addILPOpts is predicated with the
necessary check.  The AdvSIMDScalar pass is disabled by default at all
optimization levels.  This patch leaves that pass disabled by default.

Also, move command-line options into ARM64TargetMachine.cpp and add a few
additional flags to aid in debugging.  This fixes an issue with the
-debug-pass=Structure flag where passes were printed, but not actually run
(i.e., AdvSIMDScalar pass).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208223 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 16:41:55 +00:00
Daniel Sanders
7858e495e9 [mips] Add highly experimental support for MIPS-I, MIPS-II, MIPS-III, and MIPS-V
Summary:
These processors will only be available for the integrated assembler at
first (CodeGen will emit a fatal error saying they are not implemented).

The intention is to work through the existing instructions and correctly
annotate the ISA they were added in so that we have a sufficiently good
base to start MIPS64r6 development. MIPS64r6 removes/re-encodes certain
instructions and I believe it is best to define ISA's using set-union's
as far as possible rather than using set-subtraction.

Reviewers: vmedic

Subscribers: emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D3569

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208221 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 16:25:22 +00:00
Justin Bogner
459a8aaee2 llvm-cov: Explicitly namespace llvm::make_unique to keep MSVC happy
This is a followup to r208171, where a call to make_unique was
disambiguated for MSVC. Disambiguate two more calls, and remove the
comment about it since this is what we do everywhere.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208219 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 16:01:27 +00:00
Rafael Espindola
6cf16a40d3 Use range loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208218 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:53:32 +00:00
Michael Zolotukhin
355e0a6460 [InstCombine] Add optimization of redundant insertvalue instructions.
rdar://problem/11861387

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208214 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:30:18 +00:00
Daniel Sanders
0c78010b88 [mips] Add FGR_32/FGR_64/GPR_64 adjectives and use then instead of FGRPredicates/GPRPredicates
Summary:
No functional change (confirmed by diffing tablegen-erated files).

Depends on D3642

Reviewers: vmedic, dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D3645

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208213 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:25:43 +00:00
Daniel Sanders
b49c582218 [mips] Add INSN_<name> adverbs and start using them instead of AdditionalPredicates overrides
Summary:
No functional change

Depends on D3641

Reviewers: vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3642

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208212 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:11:46 +00:00
Evgeniy Stepanov
8a387a7aee [msan] Fix -fsanitize=memory -fno-integrated-as.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208211 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:10:51 +00:00
Tim Northover
04a359f768 AArch64/ARM64: optimise vector selects & enable test
When performing a scalar comparison that feeds into a vector select,
it's actually better to do the comparison on the vector side: the
scalar route would be "CMP -> CSEL -> DUP", the vector is "CM -> DUP"
since the vector comparisons are all mask based.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208210 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 14:10:27 +00:00
Daniel Sanders
b1c5f88237 [mips] Add ISA_<name> adverbs and start using them instead of AdditionalPredicates overrides
Summary:
One small functional change. The recently added PAUSE instruction now has
the HasStdEnc predicate which was accidentally removed by a Requires<>.

Depends on D3640

Reviewers: vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3641

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208209 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 13:57:22 +00:00
Rafael Espindola
2842c051b3 Remove the UseCFI option from createAsmStreamer.
We were already always passing true, this just removes the option.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208205 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 13:00:43 +00:00
Ed Maste
fe0b2279a8 DebugInfo: Use enum instead of unsigned
This makes debuging DebugInfo generation with LLDB a little more pleasant.

Differential Revision: http://reviews.llvm.org/D3626


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208202 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:49:08 +00:00
Daniel Sanders
b2d170d61b [mips] Continue splitting Instruction.Predicates into smaller lists and re-join them with !listconcat
Summary:
Move IsGP64bit into GPRPredicates, and IsFP64bit/NotFP64bit into FGRPredicates

No functional change (confirmed by diffing tablegen-erated files).

Depends on D3639

Reviewers: vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3640

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208201 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:48:37 +00:00
James Molloy
2712c87cfe [ARM64-BE] Fix fast-isel, and add appropriate RUN lines to appropriate tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208200 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:33:55 +00:00
James Molloy
d93d214a67 [ARM64-BE] Fix variable-argument saving.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208199 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:33:48 +00:00
James Molloy
fca7f5c585 [ARM64-BE] Implement the lane-twiddling logic at AAPCS boundaries for big endian.
The AAPCS states that values passed in registers must have a value as though
they had been loaded with "LDR". LDR is equivalent to "LD1.64 vX.1D" - that is,
loading scalars to vector registers and loading 1-element vectors is equivalent.

The logic implemented here is to ensure that at all call boundaries and during
formal argument lowering all vectors are treated as their bitwidth-based floating
point scalar counterpart, which is always one of f64 or f128 (v2i32 -> f64,
v4i32 -> f128 etc). A BITCAST is inserted so that the appropriate REV will be
generated during code generation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208198 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:33:41 +00:00
Daniel Sanders
1caec99d5d [mips] Move IsFP64bit/NotFP64bit to the front of the AdditionalPredicates list
Summary:
This makes it easier to prove a more complicated change in the next commit
is non-functional.

Reviewers: vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3639

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208197 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 12:27:46 +00:00
James Molloy
737c2ac4fc [ARM64-BE] Implement the crazy bitcast handling for big endian vectors.
Because we've canonicalised on using LD1/ST1, every time we do a bitcast
between vector types we must do an equivalent lane reversal.

Consider a simple memory load followed by a bitconvert then a store.
  v0 = load v2i32
  v1 = BITCAST v2i32 v0 to v4i16
       store v4i16 v2

In big endian mode every memory access has an implicit byte swap. LDR and
STR do a 64-bit byte swap, whereas LD1/ST1 do a byte swap per lane - that
is, they treat the vector as a sequence of elements to be byte-swapped.
The two pairs of instructions are fundamentally incompatible. We've decided
to use LD1/ST1 only to simplify compiler implementation.

LD1/ST1 perform the equivalent of a sequence of LDR/STR + REV. This makes
the original code sequence:  v0 = load v2i32

  v1 = REV v2i32                  (implicit)
  v2 = BITCAST v2i32 v1 to v4i16
  v3 = REV v4i16 v2               (implicit)
       store v4i16 v3

But this is now broken - the value stored is different to the value loaded
due to lane reordering. To fix this, on every BITCAST we must perform two
other REVs:

  v0 = load v2i32
  v1 = REV v2i32                  (implicit)
  v2 = REV v2i32
  v3 = BITCAST v2i32 v2 to v4i16
  v4 = REV v4i16
  v5 = REV v4i16 v4               (implicit)
       store v4i16 v5

This means an extra two instructions, but actually in most cases the two REV
instructions can be combined into one. For example:
  (REV64_2s (REV64_4h X)) === (REV32_4h X)

There is also no 128-bit REV instruction. This must be synthesized with an
EXT instruction.

Most bitconverts require some sort of conversion. The only exceptions are:
  a) Identity conversions -  vNfX <-> vNiX
  b) Single-lane-to-scalar - v1fX <-> fX or v1iX <-> iX

Even though there are hundreds of changed lines, I have a fairly high confidence
that they are somewhat correct. The changes to add two REV instructions per
bitcast were pretty mechanical, and once I'd done that I threw the resulting
.td at a script I wrote which combined the two REVs together (and added
an EXT instruction, for f128) based on an instruction description I gave it.

This was much less prone to error than doing it all manually, plus my brain
would not just have melted but would have vapourised.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208194 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 11:28:53 +00:00
James Molloy
1f890ce2dc [ARM64-BE] Predicate VLDR/VSTR for vectors as little-endian only. We must use LD1/ST1 on big-endian.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208193 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 11:28:45 +00:00