Commit Graph

113335 Commits

Author SHA1 Message Date
Rafael Espindola
8eeedf74d3 Put each jump table in an independent section if the function is too.
This allows the linker to GC both, fixing pr22557.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228937 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 17:16:46 +00:00
Benjamin Kramer
a858be4291 Fix accidental bit flip.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228936 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 16:30:00 +00:00
Benjamin Kramer
4301b5fd8b CoverageMapping: Bitvectorize code. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228934 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 16:18:07 +00:00
James Molloy
28a123abaf [LoopRerolling] Be more forgiving with instruction order.
We can't solve the full subgraph isomorphism problem. But we can
allow obvious cases, where for example two instructions of different
types are out of order. Due to them having different types/opcodes,
there is no ambiguity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228931 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 15:54:14 +00:00
Benjamin Kramer
d913d9d2c3 MathExtras: Bring Count(Trailing|Leading)Ones and CountPopulation in line with countTrailingZeros
Update all callers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228930 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 15:35:40 +00:00
Tim Northover
6950b93dfd Triple: refactor redundant code.
Should be no functional change, since most of the logic removed was
completely pointless (after some previous refactoring) and the rest
duplicated elsewhere.

Patch by Kamil Rytarowski.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228926 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 15:12:13 +00:00
Michael Kuperstein
fb107d8bf0 [X86] Call frame optimization - allow stack-relative movs to be folded into a push
Since we track esp precisely, there's no reason not to allow this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228924 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 14:17:35 +00:00
Andrea Di Biagio
44926033f6 [TTI] Teach the cost heuristic how to query TLI to check if a zext/trunc is 'free' for the target.
Now that SimplifyCFG uses TTI for the cost heuristic, we can teach BasicTTIImpl
how to query TLI in order to get a more accurate cost for truncates and
zero-extends.

Before this patch, the basic cost heuristic in TargetTransformInfoImplCRTPBase
would have conservatively returned a 'default' TCC_Basic for all zero-extends,
and TCC_Free for truncates on native types.

This patch improves the heuristic so that we query TLI (if available) to get
more accurate answers. If TLI is available, then methods 'isZExtFree' and
'isTruncateFree' can be used to check if a zext/trunc is free for the target.

Added more test cases to SimplifyCFG/X86/speculate-cttz-ctlz.ll.
With this change, SimplifyCFG is now able to speculate a 'cheap' cttz/ctlz
immediately followed by a free zext/trunc.

Differential Revision: http://reviews.llvm.org/D7585


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228923 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 14:17:24 +00:00
Benjamin Kramer
c70b2070db BitVector: Remove manual bit width dispatch, this is handled by templates
NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228922 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 14:02:58 +00:00
Benjamin Kramer
9df4111876 MathExtras: Parametrize count(Trailing|Leading)Zeros on the type size.
Otherwise we will always select the generic version for e.g. unsigned
long if uint64_t is typedef'd to 'unsigned long long'. Also remove
enable_if hacks in favor of static_assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228921 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 13:47:29 +00:00
Asiri Rathnayake
b0d513e1eb ARM: Fix another regression introduced in r223113
The changes in r223113 (ARM modified-immediate syntax) have broken
instructions like:
  mov r0, #~0xffffff00
The problem is that I've added a spurious range check on the immediate
operand to ensure that it lies between INT32_MIN and UINT32_MAX. While
this range check is correct in theory, it causes problems because the
operand is stored in an int64_t (by MC). So valid 32-bit constants like
\#~0xffffff00 become out of range. The solution is to simply remove this
range check. It is not possible to validate the range of the immediate
operand with the current setup because: 1) The operand is stored in an
int64_t by MC, 2) The immediate can be of the forms #imm, #-imm, #~imm
or even #((~imm)) etc. So we just chop the value to 32 bits and use it.

Also noted that the original range check was note tested by any of the
unit tests. I've added a new test to cover #~imm kind of operands.

Change-Id: I411e90d84312a2eff01b732bb238af536c4a7599

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228920 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 13:37:28 +00:00
Dmitry Vyukov
95fa2f9326 tsan: do not instrument not captured values
I've built some tests in WebRTC with and without this change. With this change number of __tsan_read/write calls is reduced by 20-40%, binary size decreases by 5-10% and execution time drops by ~5%. For example:

$ ls -l old/modules_unittests new/modules_unittests
-rwxr-x--- 1 dvyukov 41708976 Jan 20 18:35 old/modules_unittests
-rwxr-x--- 1 dvyukov 38294008 Jan 20 18:29 new/modules_unittests
$ objdump -d old/modules_unittests | egrep "callq.*__tsan_(read|write|unaligned)" | wc -l
239871
$ objdump -d new/modules_unittests | egrep "callq.*__tsan_(read|write|unaligned)" | wc -l
148365

http://reviews.llvm.org/D7069



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228917 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 09:55:28 +00:00
Elena Demikhovsky
f41b8e3e49 AVX-512: Fixed the "test" operation for i1 type
Using KORTESTW for comparison i1 value with zero was wrong since the instruction tests 16 bits.
KORTESTW may be used with KSHIFTL+KSHIFTR that clean the 15 upper bits.
I removed (X86cmp i1, 0) pattern and zero-extend i1 to i8 and then use TESTB.

There are some cases where i1 is in the mask register and the upper bits are already zeroed.
Then KORTESTW is the better solution, but it is subject for optimization.
Meanwhile, I'm fixing the correctness issue.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228916 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 08:40:34 +00:00
Michael Kuperstein
fd98d3be55 [X86] A heuristic to estimate the size impact for converting stack-relative parameter movs to pushes
This gives a rough estimate of whether using pushes instead of movs is profitable, in terms of size.
We go over all calls in the MachineFunction and compute:
a) For each callsite that can not use pushes, the penalty of not having a reserved call frame.
b) For each callsite that can use pushes, the gain of actually replacing the movs with pushes (and the potential penalty of having to readjust the stack).

Differential Revision: http://reviews.llvm.org/D7561

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228915 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 08:36:35 +00:00
Ahmed Bougacha
9e9bde9b54 [CodeGen] Don't blindly combine (fp_round (fp_round x)) to (fp_round x).
We used to do this DAG combine, but it's not always correct:
If the first fp_round isn't a value preserving truncation, it might
introduce a tie in the second fp_round, that wouldn't occur in the
single-step fp_round we want to fold to.
In other words, double rounding isn't the same as rounding.

Differential Revision: http://reviews.llvm.org/D7571


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228911 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 06:15:29 +00:00
George Burgess IV
c571d114ba Fixed a bug where CFLAA would crash the compiler.
We would crash if we couldn't locate a Function that either Location's
Value belonged to. Now we just print out a debug message and return 
conservatively.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228901 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 03:07:07 +00:00
Chandler Carruth
ffc97a6ae1 [slp] Fix a nasty bug in the SLP vectorizer that Joerg pointed out.
Apparently some code finally started to tickle this after my
canonicalization changes to instcombine.

The bug stems from trying to form a vector type out of scalars that
aren't compatible at all. In this example, from x86_mmx values. The code
in the vectorizer that checks for reasonable types whas checking for
aggregates or vectors, but there are lots of other types that should
just never reach the vectorizer.

Debugging this was made more confusing by the lie in an assert in
VectorType::get() -- it isn't that the types are *primitive*. The types
must be integer, pointer, or floating point types. No other types are
allowed.

I've improved the assert and added a helper to the vectorizer to handle
the element type validity checks. It now re-uses the VectorType static
function and then further excludes weird target-specific types that we
probably shouldn't be touching here (x86_fp80 and ppc_fp128). Neither of
these are really reachable anyways (neither 80-bit nor 128-bit things
will get vectorized) but it seems better to just eagerly exclude such
nonesense.

I've added a test case, but while it definitely covers two of the paths
through this code there may be more paths that would benefit from test
coverage. I'm not familiar enough with the SLP vectorizer to synthesize
test cases for all of these, but was able to update the code itself by
inspection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228899 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 02:30:56 +00:00
Hal Finkel
091acf253b [PowerPC] Mark jumps as expensive (using using CR bits)
On PowerPC, which has a full set of logical operations on (its multiple sets
of) condition-register bits, it is not profitable to break of complex
conditions feeding a jump into multiple jumps. We can turn off this feature of
CGP/SDAGBuilder by marking jumps as "expensive".

P7 test-suite speedups (no regressions):
MultiSource/Benchmarks/FreeBench/pcompress2/pcompress2
	-0.626647% +/- 0.323583%
MultiSource/Benchmarks/Olden/power/power
	-18.2821% +/- 8.06481%

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228895 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 01:02:52 +00:00
Zachary Turner
6f4e8d27e9 Revert "Change Path::filename_pos() to skip the drive letter."
This reverts commit 228874.  For some reason users reported
seeing Clang taking up 25+GB of memory and bringing down
machines with this change.  Reverting until we figure it out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228890 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 00:05:49 +00:00
Rafael Espindola
9fbdbaa2d1 Invert the section relocation map.
It now points from rel section to section. Use it to set sh_info, avoiding
a brittle name lookup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228889 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 23:38:33 +00:00
Rafael Espindola
723be8820c Use the existing SymbolTableIndex instead of doing a lookup. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228888 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 23:33:46 +00:00
Rafael Espindola
3ce0dd9867 Create the Seciton -> Rel Section map when it is first needed. NFC.
Saves a walk over every section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228886 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 23:17:48 +00:00
Tim Northover
7f75841a73 DeadArgElim: aggregate Return assessment properly.
I mistakenly thought the liveness of each "RetVal(F, i)" depended only on F. It
actually depends on the index too, which means we need to be careful about how
the results are combined before return. In particular if a single Use returns
Live, that counts for the entire object, at the granularity we're considering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228885 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 23:13:11 +00:00
Rafael Espindola
e3199deda2 Remove unused argument. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228884 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 23:11:18 +00:00
David Majnemer
7418cb0ec6 Unbreak buildbots
The next offset should be updated as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228883 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 22:51:55 +00:00
Rafael Espindola
98f9153ded Don't recompute the entire section map just to add 3 entries. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228881 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 22:41:26 +00:00
David Majnemer
f50e261e1e MC, COFF: Align section contents to a four byte boundary
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228879 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 22:22:30 +00:00
Zachary Turner
b357516cb4 Change Path::filename_pos() to skip the drive letter.
For Windows, filename_pos() tries to find the filename by
searching for separators after the last :.  Instead, it should
really check for the only location that a : is valid, which is
in the second character, and search for separators after that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228874 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 21:16:35 +00:00
Rafael Espindola
f97b99e41c Remove unused argument. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228873 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 21:08:00 +00:00
Mehdi Amini
23af697ae6 Reassociate: cannot negate a INT_MIN value
Summary:
When trying to canonicalize negative constants out of
multiplication expressions, we need to check that the
constant is not INT_MIN which cannot be negated.

Reviewers: mcrosier

Reviewed By: mcrosier

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7286

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228872 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 19:54:44 +00:00
Tom Stellard
293dfe59a5 R600/SI: Disable subreg liveness
This is temporary while we try to fix a crash in the register coalescer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228861 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 18:24:53 +00:00
Simon Pilgrim
d606d6bfe1 [X86][SSE] Added dual vector truncation tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228857 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 18:14:35 +00:00
Adrian Prantl
4058639603 Allow DIBuilder::replaceVTableHolder() to work with temporary nodes,
tested via the clang test CodeGenCXX/vtable-holder-self-reference.cpp .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228854 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:45:10 +00:00
Adrian Prantl
fe98d69578 Add a trackIfUnresolved to DIBuilder::createInheritance(),
tested via the clang test CodeGenCXX/vtable-holder-self-reference.cpp .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228853 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:45:08 +00:00
Adrian Prantl
71a70be163 Generalize DIBuilder's createReplaceableForwardDecl() to a more flexible
createReplaceableCompositeType() that allows to create non-forward-declared
temporary nodes.

Paired commit with CFE.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228852 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:45:05 +00:00
Tom Stellard
28f550eed1 R600: Split AMDGPUPassConfig into R600PassConfig and GCNPassConfig
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228850 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:11:51 +00:00
Tom Stellard
5b98db607b R600: Create an R600TargetMachine for pre-gcn GPUs
No functinality change. R600TargetMachine inherits from
AMDGPUTargetMachine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228849 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:11:50 +00:00
Tom Stellard
946f5e91ef R600/SI: Fix -march in test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228848 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 17:11:48 +00:00
Jan Wen Voung
0dfec56734 Gold-plugin: Broaden scope of get/release_input_file to scope of Module.
Summary:
Move calls to get_input_file and release_input_file out of
getModuleForFile(). Otherwise release_input_file may end up
unmapping a view of the file while the view is still being
used by the Module (on 32-bit hosts).

Fix for PR22482.

Test Plan: Add test using --no-map-whole-files.

Reviewers: rafael, nlewycky

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7539

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228842 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 16:12:50 +00:00
Jonas Paulsson
fc58cf7676 Fix SelectionDAG compile time issue with alias analysis.
Add new token factor node and its users to worklist if alias analysis is
turned on, in DAGCombiner::visitTokenFactor(). Alias analysis may cause
a lot of new token factors to be inserted into the DAG, and they need to
be optimized to avoid significant slow-downs.

Reviewed by Hal Finkel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228841 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 16:10:31 +00:00
Sanjay Patel
cb2ff33a8a fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228836 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 15:00:41 +00:00
Sanjay Patel
00fb386b23 fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228835 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 15:00:19 +00:00
Sanjay Patel
57fb1850e2 fixed to test features, not CPUs
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228834 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 14:58:25 +00:00
Rafael Espindola
831855275d Don't repeat name in comment and clang-format a function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228831 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 14:44:17 +00:00
Marek Olsak
c0021e43ea R600/SI: Enable a lot of existing tests for VI (squashed commits)
This is a union of these commits:

* R600/SI: Enable more tests for VI which need no changes

* R600/SI: Enable V_BCNT tests for VI
    Differences:
    - v_bcnt_..._e32 -> _e64
    - s_load_dword* inline offset is in bytes instead of dwords

* R600/SI: Enable all tests for VI which use S_LOAD_DWORD
    The inline offset is changed from dwords to bytes.

* R600/SI: Enable LDS tests for VI
    Differences:
    - the s_load_dword inline offset changed from dwords to bytes
    - the tests checked very little on CI, so they have been fixed to check all
      instructions that "SI" checked

* R600/SI: Enable lshr tests for VI

* R600/SI: Fix divrem64 tests
    - "v_lshl_64" was missing "b" before "64"
    - added VI-NOT checks

* R600/SI: Enable the SI.tid test for VI

* R600/SI: Enable the frem test for VI
    Also, the frem_f64 checking is added for CI-VI.

* R600/SI: Add VI tests for rsq.clamped

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228830 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 14:26:46 +00:00
Andrea Di Biagio
f033db57e9 [TTI] Improved cost heuristic for cttz/ctlz calls.
This patch is a follow-up of r228826 (see code-review: D7506).

Now that SimplifyCFG uses TargetTransformInfo for cost analysis, we 
have to fix the cost heuristic for intrinsic calls to cttz/ctlz.

This patch defines method 'getIntrinsicCost' in BasicTTIImpl: now, BasicTTIImpl
queries TLI to check if a call to cttz/ctlz is cheap for the target.

Added test cases in Transforms/SimplifyCFG/X86 to verify that on x86,
SimplifyCFG only speculates a call to cttz/ctlz if it is cheap.

Differential Revision: http://reviews.llvm.org/D7554


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228829 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 14:22:18 +00:00
James Molloy
1777ae7a05 Make buildbots better.
This testcase change was associated incorrectly to a followup commit in my git tree, not the base commit. Sorry!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228827 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 12:24:09 +00:00
James Molloy
4de471dd0a [SimplifyCFG] Swap to using TargetTransformInfo for cost
analysis.

We're already using TTI in SimplifyCFG, so remove the hard-baked "cheapness"
heuristic and use TTI directly. Generally NFC intended, but we're using a slightly
different heuristic now so there is a slight test churn.

Test changes:
  * combine-comparisons-by-cse.ll: Removed unneeded branch check.
  * 2014-08-04-muls-it.ll: Test now doesn't branch but emits muleq.
  * coalesce-subregs.ll: Superfluous block check.
  * 2008-01-02-hoist-fp-add.ll: fadd is safe to speculate. Change to udiv.
  * PhiBlockMerge.ll: Superfluous CFG checking code. Main checks still present.
  * select-gep.ll: A variable GEP is not expensive, just TCC_Basic, according to the TTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228826 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 12:15:41 +00:00
Daniel Sanders
7b91359226 [mips] Merge disassemblers into a single implementation.
Summary:
Currently we have Mips32 and Mips64 disassemblers and this causes the target
triple to affect the disassembly despite all the relevant information being in
the ELF header. These implementations do not need to be separate.

This patch merges them together such that the appropriate tables are checked
for the subtarget (e.g. Mips64 is checked when GP64 is enabled).

Reviewers: vmedic

Reviewed By: vmedic

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7498

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228825 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 11:28:56 +00:00
James Molloy
caba7561ae [LoopReroll] Introduce the concept of DAGRootSets.
A DAGRootSet models an induction variable being used in a rerollable
loop. For example:

   x[i*3+0] = y1
   x[i*3+1] = y2
   x[i*3+2] = y3

   Base instruction -> i*3
                    +---+----+
                   /    |     \
               ST[y1]  +1     +2  <-- Roots
                        |      |
                      ST[y2] ST[y3]

There may be multiple DAGRootSets, for example:

   x[i*2+0] = ...   (1)
   x[i*2+1] = ...   (1)
   x[i*2+4] = ...   (2)
   x[i*2+5] = ...   (2)
   x[(i+1234)*2+5678] = ... (3)
   x[(i+1234)*2+5679] = ... (3)

This concept is similar to the "Scale" member used previously, but allows
multiple independent sets of roots based off the same induction variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228821 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-11 09:19:47 +00:00