Commit Graph
100 Commits
Author SHA1 Message Date
Chandler Carruth ea604d92ef [MBP] Spell the conditions the same way through out this if statement.
NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235009 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-15 13:39:42 +00:00
Chandler Carruth 016e977564 [MBP] Sink a comment into the if block to which it pertains. This makes
the content of the comment make much more sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235007 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-15 13:26:41 +00:00
Chandler Carruth ec07ff56b9 [MBP] Fix a really misleading typo in a comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235006 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-15 13:19:54 +00:00
Chandler Carruth ef81f7c255 [ADT] Teach MapVector to support a swap member. Will be used in
a subsequent commit in Clang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233159 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-25 00:50:21 +00:00
Chandler Carruth 8ec61c101a Fix a grammar issue I introduced.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231894 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 00:19:01 +00:00
Chandler Carruth bc026689ab Inspired by r231891, use gender neutral pronouns in the places I've
found in LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231893 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 00:15:44 +00:00
Chandler Carruth 5c12640642 [Modules] Include the header needed for make_unique, otherwise we can't
build this header in a module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231561 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 10:55:47 +00:00
Chandler Carruth 24a6fb0a17 Teach the LLVM CMake build how to explicitly use libc++abi when using
libc++. This lets me almost self-host on Linux with libc++ and libc++abi
very simply.

Currently, MCJIT and OrcJIT are failing due to uncaught exceptions, and
the Go binding tests are failing to build due to not linking in the
correct C++ standard library.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231560 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 10:30:34 +00:00
Chandler Carruth 60557beded [PM] Fixup for r231556 where I missed a dependency on intrinsics
generation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231558 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 09:08:20 +00:00
Chandler Carruth 2349136630 [PM] Create a separate library for high-level pass management code.
This will provide the analogous replacements for the PassManagerBuilder
and other code long term. This code is extracted from the opt tool
currently, and I plan to extend it as I build up support for using the
new pass manager in Clang and other places.

Mailing this out for review in part to let folks comment on the terrible names
here. A brief word about why I chose the names I did.

The library is called "Passes" to try and make it clear that it is a high-level
utility and where *all* of the passes come together and are registered in
a common library. I didn't want it to be *limited* to a registry though, the
registry is just one component.

The class is a "PassBuilder" but this name I'm less happy with. It doesn't
build passes in any traditional sense and isn't a Builder-style API at all. The
class is a PassRegisterer or PassAdder, but neither of those really make a lot
of sense. This class is responsible for constructing passes for registry in an
analysis manager or for population of a pass pipeline. If anyone has a better
name, I would love to hear it. The other candidate I looked at was
PassRegistrar, but that doesn't really fit either. There is no register of all
the passes in use, and so I think continuing the "registry" analog outside of
the registry of pass *names* and *types* is a mistake. The objects themselves
are just objects with the new pass manager.

Differential Revision: http://reviews.llvm.org/D8054

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231556 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-07 09:02:36 +00:00
Chandler Carruth bb535bcc20 [MBP] Use range based for-loops throughout this code. Several had
already been added and the inconsistency made choosing names and
changing code more annoying. Plus, wow are they better for this code!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231347 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 03:19:05 +00:00
Chandler Carruth 35742dd20c [MBP] NFC, run clang-format over this code and tweak things to make the
result reasonable.

This code predated clang-format and so there was a reasonable amount of
crufty formatting that had accumulated. This should ensure that neither
myself nor others end up with formatting-only changes sneaking into
other fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231341 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 02:35:31 +00:00
Chandler Carruth 559a329625 [MBP] This is no longer 'block-placement2'. ;] The old variants are long
gone, update this code to reflect that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231340 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 02:28:25 +00:00
Chandler Carruth 4197c13062 [MBP] Revert r231238 which attempted to fix a nasty bug where MBP is
just arbitrarily interleaving unrelated control flows once they get
moved "out-of-line" (both outside of natural CFG ordering and with
diamonds that cannot be fully laid out by chaining fallthrough edges).

This easy solution doesn't work in practice, and it isn't just a small
bug. It looks like a very different strategy will be required. I'm
working on that now, and it'll again go behind some flag so that
everyone can experiment and make sure it is working well for them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231332 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-05 01:07:03 +00:00
Chandler Carruth 67fade9110 [MBP] Fix a really horrible bug in MachineBlockPlacement, but behind
a flag for now.

First off, thanks to Daniel Jasper for really pointing out the issue
here. It's been here forever (at least, I think it was there when
I first wrote this code) without getting really noticed or fixed.

The key problem is what happens when two reasonably common patterns
happen at the same time: we outline multiple cold regions of code, and
those regions in turn have diamonds or other CFGs for which we can't
just topologically lay them out. Consider some C code that looks like:

  if (a1()) { if (b1()) c1(); else d1(); f1(); }
  if (a2()) { if (b2()) c2(); else d2(); f2(); }
  done();

Now consider the case where a1() and a2() are unlikely to be true. In
that case, we might lay out the first part of the function like:

  a1, a2, done;

And then we will be out of successors in which to build the chain. We go
to find the best block to continue the chain with, which is perfectly
reasonable here, and find "b1" let's say. Laying out successors gets us
to:

  a1, a2, done; b1, c1;

At this point, we will refuse to lay out the successor to c1 (f1)
because there are still un-placed predecessors of f1 and we want to try
to preserve the CFG structure. So we go get the next best block, d1.

... wait for it ...

Except that the next best block *isn't* d1. It is b2! d1 is waaay down
inside these conditionals. It is much less important than b2. Except
that this is exactly what we didn't want. If we keep going we get the
entire set of the rest of the CFG *interleaved*!!!

  a1, a2, done; b1, c1; b2, c2; d1, f1; d2, f2;

So we clearly need a better strategy here. =] My current favorite
strategy is to actually try to place the block whose predecessor is
closest. This very simply ensures that we unwind these kinds of CFGs the
way that is natural and fitting, and should minimize the number of cache
lines instructions are spread across.

It also happens to be *dead simple*. It's like the datastructure was
specifically set up for this use case or something. We only push blocks
onto the work list when the last predecessor for them is placed into the
chain. So the back of the worklist *is* the nearest next block.

Unfortunately, a change like this is going to cause *soooo* many
benchmarks to swing wildly. So for now I'm adding this under a flag so
that we and others can validate that this is fixing the problems
described, that it seems possible to enable, and hopefully that it fixes
more of our problems long term.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231238 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-04 12:18:08 +00:00
Chandler Carruth c4179ffed3 [x86] Run most of the rest of the shuffle combining over non-128-bit
vectors. This lets us fix the rest of the v16 lowering problems when
pshufb is clearly better.

We might still be able to improve some of the lowerings by enabling the
other combine-based rewriting to fire for non-128-bit vectors, but this
at least should remove any regressions from using the fancy v16i16
lowering strategy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230753 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 12:13:14 +00:00
Chandler Carruth 2d58cc5f1b [x86] Teach a bunch of the x86-specific shuffle combining to work with
256-bit vectors as well as 128-bit vectors. Fixes some of the redundant
shuffles for v16i16.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230752 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 11:45:13 +00:00
Chandler Carruth 8c71e440a2 [x86] Make the v8i16 clever single-input shuffle lowering usable for
repeated 128-bit lane shuffles of wider vector types and use it to lower
256-bit v16i16 vector shuffles where applicable.

This should let us perfectly lowering the pattern of pshuflw and pshufhw
even for AVX2 256-bit patterns.

I've not added AVX-512 support, but it should be trivial for someone
working on that to wire up.

Note that currently this generates bad, long shuffle chains because we
don't combine 256-bit target shuffles. The subsequent patches will fix
that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230751 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 11:33:46 +00:00
Chandler Carruth f5651f8ab6 [x86] Add a bunch more tests for v16i16 shuffles. All of these are taken
by mirroring v8i16 test cases across both 128-bit lanes. This should
highlight problems where we aren't correctly using 128-bit shuffles to
implement things.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230750 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 11:25:10 +00:00
Chandler Carruth b1961a3896 [x86] Make the single-input v8i16 lowering directly recurse rather than
going back through the entire vector shuffle lowering.

This is an important step to being able to re-use this logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230743 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 09:11:38 +00:00
Chandler Carruth b54c36fb4d [x86] Fix PR22706 where we would incorrectly try lower a v32i8 dynamic
blend as legal.

We made the same mistake in two different places. Whenever we are custom
lowering a v32i8 blend we need to check whether we are custom lowering
it only for constant conditions that can be shuffled, or whether we
actually have AVX2 and full dynamic blending support on bytes. Both are
fixed, with comments added to make it clear what is going on and a new
test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230695 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 22:15:34 +00:00
Chandler Carruth 205a9a3aec [x86] Restructure the comments and the conditions for handling
dynamic blends.

This makes it much more clear what is going on. The case we're handling
is that of dynamic conditions, and we're bailing when the nature of the
vector types and subtarget preclude lowering the dynamic condition
vselect as an actual blend.

No functionality changed here, but this will make a subsequent bug-fix
to this code much more clear.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230690 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 21:29:06 +00:00
Chandler Carruth 9b9d0fcfe9 [x86] Re-order the combines of select in the X86 backend. This doesn't
change functionality, but makes it more clear that the dynamic case and
the shuffle case don't overlap in any interesting way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230689 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 21:21:36 +00:00
Chandler Carruth 34f88924e1 [x86] Add an assert to catch if we ever try to blend a v32i8 without
AVX2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230688 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 21:18:20 +00:00
Chandler Carruth eabb1227f6 [x86] Sink the single-input v8i16 lowering code that is actually
formulaic into the top v8i16 lowering routine.

This makes the generalized lowering a completely general and single path
lowering which will allow generalizing it in turn for multiple 128-bit
lanes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230623 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 11:00:40 +00:00
Chandler Carruth 177498a4e0 [x86] Remove a SimpleTy usage. No need for it here, we already have the
MVT.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230622 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 10:37:01 +00:00
Chandler Carruth 19c267aed1 [x86] Make the vector shuffle helpers order the SDLoc and MVT arguments.
This ordering matches that of DAG.getNode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230617 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-26 08:19:24 +00:00
Chandler Carruth 634fc5f26b [x86] Switching the shuffle equivalence test to a variadic template was
the wrong answer. We also got initializer lists which are *way* cleaner
for this kind of thing. Let's use those and make this a normal, boring
functionn accepting ArrayRef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230004 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 10:47:28 +00:00
Chandler Carruth efbbaefea5 [x86] Remove the old vector shuffle lowering code and its flag.
The new shuffle lowering has been the default for some time. I've
enabled the new legality testing by default with no really blocking
regressions. I've fuzz tested this very heavily (many millions of fuzz
test cases have passed at this point). And this cleans up a ton of code.
=]

Thanks again to the many folks that helped with this transition. There
was a lot of work by others that went into the new shuffle lowering to
make it really excellent.

In case you aren't using a diff algorithm that can handle this:
  X86ISelLowering.cpp: 22 insertions(+), 2940 deletions(-)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229964 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 04:25:04 +00:00
Chandler Carruth 07ef8904ad [x86] Now that the new vector shuffle legality is enabled and everything
is going well, remove the flag and the code for the old legality tests.

This is the first step toward removing the entire old vector shuffle
lowering. *Much* more code to delete coming up next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229963 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 03:59:35 +00:00
Chandler Carruth 38749b8e07 [x86] Make the new vector shuffle legality test on by default, which
reflects the fact that the x86 backend can in fact lower any shuffle you
want it to with reasonably high code quality.

My recent work on the new vector shuffle has made this regress *very*
little. The diff in the test cases makes me very, very happy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229958 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 03:05:47 +00:00
Chandler Carruth 4fd100f9e9 [x86] Clean up a couple of test cases with the new update script. Split
one test case that is only partially tested in 32-bits into two test
cases so that the script doesn't generate massive spews of tests for the
cases we don't care about.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229955 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 02:44:13 +00:00
Chandler Carruth 90b8e791ac Revert r229944: EH: Prune unreachable resume instructions during Dwarf EH preparation
This doesn't pass 'ninja check-llvm' for me. Lots of tests, including
the ones updated, fail with crashes and other explosions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229952 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 02:15:36 +00:00
Chandler Carruth b7012af85f [x86] Delete still more piles of complex code now that we have a good
systematic lowering of v8i16.

This required a slight strategy shift to prefer unpack lowerings in more
places. While this isn't a cut-and-dry win in every case, it is in the
overwhelming majority. There are only a few places where the old
lowering would probably be a touch faster, and then only by a small
margin.

In some cases, this is yet another significant improvement.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229859 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 15:21:57 +00:00
Chandler Carruth c57e90422f [x86] Teach the unpack lowering how to lower with an initial unpack in
addition to lowering to trees rooted in an unpack.

This saves shuffles and or registers in many various ways, lets us
handle another class of v4i32 shuffles pre SSE4.1 without domain
crosses, etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229856 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 15:06:13 +00:00
Chandler Carruth 7f583a4201 [x86] Dramatically improve v8i16 shuffle lowering by not using its
terribly complex partial blend logic.

This code path was one of the more complex and bug prone when it first
went in and it hasn't faired much better. Ultimately, with the simpler
basis for unpack lowering and support bit-math blending, this is
completely obsolete. In the worst case without this we generate
different but equivalent instructions. However, in many cases we
generate much better code. This is especially true when blends or pshufb
is available.

This does expose one (minor) weakness of the unpack lowering that I'll
try to address.

In case you were wondering, this is actually a big part of what I've
been trying to pull off in the recent string of commits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229853 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 14:08:24 +00:00
Chandler Carruth 943b2ca2de [x86] Remove the final fallback in the v8i16 lowering that isn't really
needed, and significantly improve the SSSE3 path.

This makes the new strategy much more clear. If we can blend, we just go
with that. If we can't blend, we try to permute into an unpack so
that we handle cases where the unpack doing the blend also simplifies
the shuffle. If that fails and we've got SSSE3, we now call into
factored-out pshufb lowering code so that we leverage the fact that
pshufb can set up a blend for us while shuffling. This generates great
code, especially because we *know* we don't have a fast blend at this
point. Finally, we fall back on decomposing into permutes and blends
because we do at least have a bit-math-based blend if we need to use
that.

This pretty significantly improves some of the v8i16 code paths. We
never need to form pshufb for the single-input shuffles because we have
effective target-specific combines to form it there, but we were missing
its effectiveness in the blends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229851 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 13:56:49 +00:00
Chandler Carruth c3d7858505 [x86] Simplify the pre-SSSE3 v16i8 lowering significantly by decomposing
them into permutes and a blend with the generic decomposition logic.

This works really well in almost every case and lets the code only
manage the expansion of a single input into two v8i16 vectors to perform
the actual shuffle. The blend-based merging is often much nicer than the
pack based merging that this replaces. The only place where it isn't we
end up blending between two packs when we could do a single pack. To
handle that case, just teach the v2i64 lowering to handle these blends
by digging out the operands.

With this we're down to only really random permutations that cause an
explosion of instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229849 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 13:15:12 +00:00
Chandler Carruth 3d4542ce3d [x86] Remove the insanely over-aggressive unpack lowering strategy for
v16i8 shuffles, and replace it with new facilities.

This uses precise patterns to match exact unpacks, and the new
generalized unpack lowering only when we detect a case where we will
have to shuffle both inputs anyways and they terminate in exactly
a blend.

This fixes all of the blend horrors that I uncovered by always lowering
blends through the vector shuffle lowering. It also removes *sooooo*
much of the crazy instruction sequences required for v16i8 lowering
previously. Much cleaner now.

The only "meh" aspect is that we sometimes use pshufb+pshufb+unpck when
it would be marginally nicer to use pshufb+pshufb+por. However, the
difference there is *tiny*. In many cases its a win because we re-use
the pshufb mask. In others, we get to avoid the pshufb entirely. I've
left a FIXME, but I'm dubious we can really do better than this. I'm
actually pretty happy with this lowering now.

For SSE2 this exposes some horrors that were really already there. Those
will have to fixed by changing a different path through the v16i8
lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229846 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 12:10:37 +00:00
Chandler Carruth 71164d08b1 [x86] The SELECT x86 DAG combine also does legalization. It used to rely
on things not being marked as either custom or legal, but we now do
custom lowering of more VSELECT nodes. To cope with this, manually
replicate the legality tests here. These have to stay in sync with the
set of tests used in the custom lowering of VSELECT.

Ideally, we wouldn't do any of this combine-based-legalization when we
have an actual custom legalization step for VSELECT, but I'm not going
to be able to rewrite all of that today.

I don't have a test case for this currently, but it was found when
compiling a number of the test-suite benchmarks. I'll try to reduce
a test case and add it.

This should at least fix the test-suite fallout on build bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229844 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 11:43:37 +00:00
Chandler Carruth ac2b1a1bb3 [x86] Add support for bit-wise blending and use it in the v8 and v16
lowering paths. I'm going to be leveraging this to simplify a lot of the
overly complex lowering of v8 and v16 shuffles in pre-SSSE3 modes.

Sadly, this isn't profitable on v4i32 and v2i64. There, the float and
double blending instructions for pre-SSE4.1 are actually pretty good,
and we can't beat them with bit math. And once SSE4.1 comes around we
have direct blending support and this ceases to be relevant.

Also, some of the test cases look odd because the domain fixer
canonicalizes these to floating point domain. That's OK, it'll use the
integer domain when it matters and some day I may be able to update
enough of LLVM to canonicalize the other way.

This restores almost all of the regressions from teaching x86's vselect
lowering to always use vector shuffle lowering for blends. The remaining
problems are because the v16 lowering path is still doing crazy things.
I'll be re-arranging that strategy in more detail in subsequent commits
to finish recovering the performance here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229836 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 10:46:52 +00:00
Chandler Carruth a8fb39af83 [x86,sdag] Two interrelated changes to the x86 and sdag code.
First, don't combine bit masking into vector shuffles (even ones the
target can handle) once operation legalization has taken place. Custom
legalization of vector shuffles may exist for these patterns (making the
predicate return true) but that custom legalization may in some cases
produce the exact bit math this matches. We only really want to handle
this prior to operation legalization.

However, the x86 backend, in a fit of awesome, relied on this. What it
would do is mark VSELECTs as expand, which would turn them into
arithmetic, which this would then match back into vector shuffles, which
we would then lower properly. Amazing.

Instead, the second change is to teach the x86 backend to directly form
vector shuffles from VSELECT nodes with constant conditions, and to mark
all of the vector types we support lowering blends as shuffles as custom
VSELECT lowering. We still mark the forms which actually support
variable blends as *legal* so that the custom lowering is bypassed, and
the legal lowering can even be used by the vector shuffle legalization
(yes, i know, this is confusing. but that's how the patterns are
written).

This makes the VSELECT lowering much more sensible, and in fact should
fix a bunch of bugs with it. However, as you'll see in the test cases,
right now what it does is point out the *hilarious* deficiency of the
new vector shuffle lowering when it comes to blends. Fortunately, my
very next patch fixes that. I can't submit it yet, because that patch,
somewhat obviously, forms the exact and/or pattern that the DAG combine
is matching here! Without this patch, teaching the vector shuffle
lowering to produce the right code infloops in the DAG combiner. With
this patch alone, we produce terrible code but at least lower through
the right paths. With both patches, all the regressions here should be
fixed, and a bunch of the improvements (like using 2 shufps with no
memory loads instead of 2 andps with memory loads and an orps) will
stay. Win!

There is one other change worth noting here. We had hilariously wrong
vectorization cost estimates for vselect because we fell through to the
code path that assumed all "expand" vector operations are scalarized.
However, the "expand" lowering of VSELECT is vector bit math, most
definitely not scalarized. So now we go back to the correct if horribly
naive cost of "1" for "not scalarized". If anyone wants to add actual
modeling of shuffle costs, that would be cool, but this seems an
improvement on its own. Note the removal of 16 and 32 "costs" for doing
a blend. Even in SSE2 we can blend in fewer than 16 instructions. ;] Of
course, we don't right now because of OMG bad code, but I'm going to fix
that. Next patch. I promise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229835 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-19 10:36:19 +00:00
Chandler Carruth 00c954ffc4 [x86] Merge checks for a recently added test case that is the same on
all SSE variants and AVX variants.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229770 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 23:20:49 +00:00
Chandler Carruth a5cc501201 [x86] Tighten the assertions to document that canonicalization has
actually removed all but a *very* small number of choices for v2i64.
Also remove dead code handling cases that simply cannot arise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229670 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 11:46:29 +00:00
Chandler Carruth 406928ebba [x86] Switch an if which is trivially true to an assert. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229669 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 11:46:27 +00:00
Chandler Carruth 72cacedbb7 [x86] Remove some more 'bit' nomenclature from the generic shift
lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229668 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 11:46:23 +00:00
Chandler Carruth 3378af8802 [x86] Fold together the two shift lowering strategies. They were doing
quite literally the same work, we just need to special case the >64-bit
element shift code emission to emit the byte shift instructions and
offsets. This also makes reasoning about each of the vector lowering
strategies easier as we don't have to remember to use both forms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229662 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 10:40:38 +00:00
Chandler Carruth 4e8a4638e9 [x86] Refactor the bit shift code the same as I just did the byte shift
code.

While this didn't have the miscompile (it used MatchLeft consistently)
it missed some cases where it could use right shifts. I've added a test
case Craig Topper came up with to exercise the right shift matching.

This code is really identical between the two. I'm going to merge them
next so that we don't keep two copies of all of this logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229655 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 09:19:58 +00:00
Chandler Carruth c9520b48ae [x86] Rewrite the byte shift detection to not use boolean variables to
track state.

I didn't like this in the code review because the pattern tends to be
error prone, but I didn't see a clear way to rewrite it. Turns out that
there were bugs here, I found them when fuzz testing our shuffle
lowering for correctness on x86.

The core of the problem is that we need to consistently test all our
preconditions for the same directionality of shift and the same input
vector. Instead, formulate this as two predicates (one doesn't depend on
the input in any way), pass things like the directionality and input
vector as inputs, and loop over the alternatives.

This fixes a pattern of very rare miscompiles coming out of this code.
Turned up roughly 4 out of every 1 million v8 shuffles in my fuzz
testing. The new code is over half a million test runs with no failures
yet. I've also fuzzed every other function in the lowering code with
over 3.5 million test cases and not discovered any other miscompiles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229642 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 07:13:48 +00:00
Chandler Carruth 4f1b92cece [shuffles] Tweak my shufflevector fuzz test generation script to produce
more useful output. No more null bytes printed, and now with a newline.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229599 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-18 01:36:45 +00:00
Chandler Carruth 1e357351be [x86] Teach the unpack lowering to try wider element unpacks.
This allows it to match still more places where previously we would have
to fall back on floating point shuffles or other more complex lowering
strategies.

I'm hoping to replace some of the hand-rolled unpack matching with this
routine is it gets more and more clever.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229463 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-17 02:12:24 +00:00
Chandler Carruth cbe6ecfc81 [x86] Add a generic unpack-targeted lowering technique. This can be used
to generically lower blends and is particularly nice because it is
available frome SSE2 onward. This removes a lot of the remaining domain
crossing blends in SSE2 code.

I'm hoping to replace some of the "interleaved" lowering hacks with
something closer to this which should be more principled. First, this
needs to learn how to detect and use other interleavings besides that of
the natural type provided. That will be a follow-up patch though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229378 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 12:28:18 +00:00
Chandler Carruth e62fbca6b7 [x86] Switch this test to use checks generated by my update script. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229377 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 12:23:22 +00:00
Chandler Carruth 29679ccc12 [x86] Add initial basic support for forming blends of v16i8 vectors.
This blend instruction is ... really lame. The register usage is insane.
As a consequence this is probably only *barely* better than 2 pshufbs
followed by a por, and that mostly because it only has to read from
a single memory location.

However, this doesn't fix as much as I kind of expected, so more to go.
Pretty sure that the ordering and delegation of v16i8 is just really,
really bad.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229373 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 10:58:23 +00:00
Chandler Carruth ab497238cb [x86] Add some more test cases for i8 vector blends.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229372 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 10:51:49 +00:00
Chandler Carruth 8b1a5559e9 [x86] Switch my usage of VariadicFunction to a "normal" variadic
template now that we can use them.

This is, of course, horribly ugly because of the required recursive
formulation. Suggestions for making it less ugly welcome.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229367 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 09:59:48 +00:00
Chandler Carruth d99cd97f85 Switch our index sequence away from template aliases and just use
classes. We can't use template aliases because on MSVC they don't appear
to work correctly in the common usage such as Format.h.

Many thanks to Zach for doing all the testing and debugging here. I just
slotted the fix into the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229362 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 08:22:35 +00:00
Chandler Carruth 454c3997b4 [x86] Teach the 128-bit vector shuffle lowering routines to take
advantage of the existence of a reasonable blend instruction.

The 256-bit vector shuffle lowering has leveraged the general technique
of decomposed shuffles and blends for quite some time, but this never
made it back into the 128-bit code, and there are a large number of
patterns where this is substantially better. For example, this removes
almost all domain crossing in vector shuffles that involve some blend
and some permutation with SSE4.1 and later. See the massive reduction
in 'shufps' for integer test cases in this commit.

This isn't perfect yet for a few reasons:

1) The v8i16 shuffle lowering continues to plague me. We don't always
   form an unpack-based blend when that would be better. But the wins
   pretty drastically outstrip the losses here.
2) The v16i8 shuffle lowering is just a disaster here. I never went and
   implemented blend support here for some terrible reason. I'll do
   that next probably. I've not updated it for now.

More variations on this technique are coming as well -- we don't
shuffle-into-unpack or shuffle-into-palignr, both of which would also be
profitable.

Note that some test cases grow significantly in the number of
instructions, but I expect to actually be faster. We use
pshufd+pshufd+blendw instead of a single shufps, but the pshufd's are
very likely to pipeline well (two ports on most modern intel chips) and
the blend is a *very* fast instruction. The domain switch penalty will
essentially always be more than a blend instruction, which is the only
increase in tree height.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229350 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 01:52:02 +00:00
Chandler Carruth aa35e012a3 [x86] Clean up a few test cases with the update script. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229349 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 01:39:50 +00:00
Chandler Carruth 3e93916175 [x86] Add the test case from PR22412, we now get this right even with
the new vector shuffle legality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229310 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 12:45:05 +00:00
Chandler Carruth fbde8bffba [x86] Teach the decomposed shuffle/blend lowering to use an early blend
when that will allow it to lower with a single permute instead of
multiple permutes.

It tries to detect when it will only have to do a single permute in
either case to maximize folding of loads and such.

This cuts a *lot* of the avx2 shuffle permute counts in half. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229309 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 12:42:15 +00:00
Chandler Carruth 72753f87f2 [SDAG] Teach the SelectionDAG to canonicalize vector shuffles of splats
directly into blends of the splats.

These patterns show up even very late in the vector shuffle lowering
where we don't have any chance for DAG combining to kick in, and
blending is a tremendously simpler operation to model. By coercing the
shuffle into a blend we can much more easily match and lower shuffles of
splats.

Immediately with this change there are significantly more blends being
matched in the x86 vector shuffle lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229308 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 12:18:12 +00:00
Chandler Carruth 3d39845812 [x86] Teach the shuffle mask equivalence test to look through build
vectors and detect equivalent inputs.

This lets the code match unpck-style instructions when only one of the
inputs are lined up but the other input is a splat and so which lanes we
pull from doesn't matter. Today, this doesn't really happen, but just by
accident. I have a patch that normalizes how we shuffle splats, and with
that patch this will be necessary for a lot of the mask equivalence
tests to work.

I don't really know how to write a test case for this specific change
until the other change lands though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229307 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 12:07:55 +00:00
Chandler Carruth 23b34c287f [x86] Tweak the ordering of unpack matching vs. element insertion, and
don't try to do element insertion for non-zero-index floating point
vectors.

We don't have any useful patterns or lowering for element insertion into
high elements of a floating point vector, and the generic shuffle
lowering will end up being better -- namely it will fall back to unpck.
But we should try to handle other forms of element insertion before
matching unpck patterns.

While this doesn't matter much right now, I'm working on a patch that
makes unpck matching much more powerful, and that patch will break
without this re-ordering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229306 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 12:01:14 +00:00
Chandler Carruth 52f1b6dbed [x86] Stop shuffling zero vectors. =]
I was somewhat surprised this pattern really came up, but it does. It
seems better to just directly handle it than try to special case every
place where we end up forming a shuffle that devolves to a shuffle of
a zero vector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229301 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 10:34:52 +00:00
Chandler Carruth 1a9c1dbe4d [x86] Use a more helpful parenthesizing of these comparisons. Silences
a -Wparentheses complaint from GCC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229300 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 10:15:20 +00:00
Chandler Carruth 46d3e580ed [x86] When splitting 256-bit vectors into 128-bit vectors, don't extract
subvectors from buildvectors. That doesn't really make any sense and it
breaks all of the down-stream matching of buildvectors to cleverly lower
shuffles.

With this, we now get the shift-based lowering of 256-bit vector
shuffles with AVX1 when we split them into 128-bit vectors. We also do
much better on the zero-extension patterns, although there remains quite
a bit of room for improvement here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229299 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 10:12:02 +00:00
Chandler Carruth 27acd682e0 [x86] Make computing the zeroable elements slightly more powerful, at
least in theory.

I don't actually have a test case that benefits from this, but
theoretically, it could come up, and I don't want to try to think about
whether this is the culprit or something else is, so I'd rather just
make this code powerful. =/ Makes me sad that I can't really test it
though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229298 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 09:33:36 +00:00
Chandler Carruth 4d2dfa703e [x86] Update some tests with the latest version of my script and llc.
This mostly adds some shuffle decode comments and cleans up indentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229296 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 09:26:15 +00:00
Chandler Carruth 62ba2b29d8 [x86] Add a slight variation on some of the other generic shuffle
lowerings -- one which decomposes into an initial blend followed by
a permute.

Particularly on newer chips, blends are handled independently of
shuffles and so this is much less bottlenecked on the single port that
floating point shuffles are executed with on Intel.

I'll be adding this lowering to a bunch of other code paths in
subsequent commits to handle still more places where we can effectively
leverage blends when they're available in the ISA.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229292 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 08:26:30 +00:00
Chandler Carruth 8e8b9bd42f [x86] Add a test case for PR22390 which was a dup of PR22377 and fixed
by r229285. This is a nice different test case though, so I'd like to
have the extra testing of these kinds of patterns.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229286 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 07:05:50 +00:00
Chandler Carruth 5ee516549f [x86] Fix PR22377, a regression with the new vector shuffle legality
test.

This was just a matter of the DAG combine for vector shuffles being too
aggressive. This is a bit of a grey area, but I think generally if we
can re-use intermediate shuffles, we should. Certainly, given the test
cases I have available, this seems like the right call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229285 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 07:01:10 +00:00
Chandler Carruth 9bb943b185 [x86] Switch a collection of tests explicitly to the new vector shuffle
legality test (essentially, everything is legal).

I'm planning to make this the default shortly, but I'd like to fix
a collection of the bugs it exposes first, and this will let me easily
test them. It also showcases both the improvements and a few of the
regressions triggered by the change. The biggest improvements by far are
the significantly reduced shuffling and domain crossing in the combining
test case. The biggest regressions are missing some clever blending
patterns.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229284 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 06:37:21 +00:00
Chandler Carruth 0294b517ac [x86] Remove the now-default-on flag for the new vector shuffle lowering
strategy from a bunch of tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229283 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 06:20:51 +00:00
Chandler Carruth da0198de41 [x86] Teach my test updating script about another quirk of the printed
asm and port the mmx vector shuffle test to it.

Not thrilled with how it handles the stack manipulation logic, but I'm
much less bothered by that than I am by updating the test manually. =]
If anyone wants to teach the test checks management script about stack
adjustment patterns, that'd be cool too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229268 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-15 00:08:01 +00:00
Chandler Carruth 15db81893f [gold] Consolidate the gold plugin options and actually search for
a gold binary explicitly. Substitute this binary into the tests rather
than just directly executing the 'ld' binary.

This should allow folks to inject a cross compiling gold binary, or in
my case to use a gold binary built and installed somewhere other than
/usr/bin/ld. It should also allow the tests to find 'ld.gold' so that
things work even if gold isn't the default on the system.

I've only stubbed out support in the makefile to preserve the existing
behavior with none of the fancy logic. If someone else wants to add
logic here, they're welcome to do so.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229251 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 09:43:57 +00:00
Chandler Carruth 96db150cec Remove a variable only used in an assert and sink its initializer into
the assert. Fixes -Wunused-variable on non-asserts builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229250 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 09:14:44 +00:00
Chandler Carruth 4d97764220 Back out two accidental changes that snuck in with r229245. Sorry these
snuck in, they weren't ready for prime time and had *nothing* to do
with that commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229248 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 09:05:58 +00:00
Chandler Carruth 45d67e923d [lit] Make the gold plugin support testing work with a python3
interpreter. Seems that's a better path than pinning to python2.7.

Thanks to Justin for prodding me toward a fix. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229247 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 09:05:56 +00:00
Chandler Carruth c9864d8a73 Revert r229224: Make the 'llvm-lit' utility defend against a system where Python3
Apparantly python2.7 also doesn't work. Awesome.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229245 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 07:11:25 +00:00
Chandler Carruth 9230ff9ba3 [lit] Make the 'llvm-lit' utility defend against a system where Python3
is the default.

The lit.cfg files are not all valid Python3 and I've no idea if anyone
is really prepared to update them. The easiest way I know of to ensure
that this script uses Python 2 is to use 'python2.7' in the command. Mac
and Linux are definitely fine with this and I think other platforms will
be as well, but if anyone struggles with this set up and has better
ideas, let me know.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229244 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 07:05:15 +00:00
Chandler Carruth 29a861abc9 [PM] Fix a compile error I introduced in r229094 and didn't notice
because I didn't have binutils set up properly to build the gold plugin.

Fixes PR22581 which was filed because this broke the build for folks
relying on the plugin. Very sorry! =]

I've gotten the plugin stuff building now as well so it shouldn't keep
happening.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229156 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 21:10:58 +00:00
Chandler Carruth 7ea33e53c7 [PM] Update the examples to reflect the removal of the
llvm/PassManager.h wrapper header and its using declarations. These now
directly use the legacy namespace.

I had updated the #include lines in my large commit but forgot that the
examples weren't being built and didn't update the code to use the
correct namespace. Sorry for the noise here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229095 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 10:21:05 +00:00
Chandler Carruth 417c5c172c [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229094 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 10:01:29 +00:00
Chandler Carruth 09c9b6f0c4 Re-sort the #include lines in bindings and examples which I managed to
miss previously.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229089 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 09:14:30 +00:00
Chandler Carruth 02d6288667 Re-sort #include lines using my handy dandy ./utils/sort_includes.py
script. This is in preparation for changes to lots of include lines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229088 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 09:09:03 +00:00
Chandler Carruth 00ae03a747 Revert a series of commits starting at r228886 which is triggering some
regressions for LLDB on Linux. Rafael indicated on lldb-dev that we
should just go ahead and revert these but that he wasn't at a computer.
The patches backed out are as follows:

r228980: Add support for having multiple sections with the name and ...
r228889: Invert the section relocation map.
r228888: Use the existing SymbolTableIndex intsead of doing a lookup.
r228886: Create the Section -> Rel Section map when it is first needed.

These patches look pretty nice to me, so hoping its not too hard to get
them re-instated. =D

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229080 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 07:52:39 +00:00
Chandler Carruth 25fa343bd8 [unroll] Concede defeat and disable the unroll analyzer for now.
The issues with the new unroll analyzer are more fundamental than code
cleanup, algorithm, or data structure changes. I've sent an email to the
original commit thread with details and a proposal for how to redesign
things. I'm disabling this for now so that we don't spend time
debugging issues with it in its current state.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229064 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 05:31:46 +00:00
Chandler Carruth e95568c0a0 [unroll] Merge the simplification and DCE estimation methods on the
UnrollAnalyzer.

Now they share a single worklist and have less implicit state between
them. There was no real benefit to separating these two things out.

I'm going to subsequently refactor things to share even more code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229062 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:39:05 +00:00
Chandler Carruth 17cc3c80ee [unroll] Remove pointless dyn_cast<>s to Instruction - the users of an
instruction must by definition be instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229061 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:33:21 +00:00
Chandler Carruth 2d38576d56 [unroll] Don't check the loop set for whether an instruction is
contained in it each time we try to add it to the worklist, just check
this when pulling it off the worklist. That way we do it at most once
per instruction with the cost of the worklist set we would need to pay
anyways.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229060 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:30:44 +00:00
Chandler Carruth b9cb5b19d9 [unroll] Change the other worklist in the unroll analyzer to be a set
vector.

In addition to dramatically reducing the work required for contrived
example loops, this also has to correct some serious latent bugs in the
cost computation. Previously, we might add an instruction onto the
worklist once for every load which it used and was simplified. Then we
would visit it many times and accumulate "savings" each time.

I mean, fortunately this couldn't matter for things like calls with 100s
of operands, but even for binary operators this code seems like it must
be double counting the savings.

I just noticed this by inspection and due to the runtime problems it can
introduce, I don't have any test cases for cases where the cost produced
by this routine is unacceptable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229059 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:27:50 +00:00
Chandler Carruth 361ac0df65 [unroll] Replace a boolean, for loop, condition, and break with
std::all_of and a lambda. Much cleaner, no functionality
changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229058 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:18:14 +00:00
Chandler Carruth 758256535c [unroll] Directly query for dead instructions.
In the unroll analyzer, it is checking each user to see if that user
will become dead. However, it first checked if that user was missing
from the simplified values map, and then if was also missing from the
dead instructions set. We add everything from the simplified values map
to the dead instructions set, so the first step is completely subsumed
by the second. Moreover, the first step requires *inserting* something
into the simplified value map which isn't what we want at all.

This also replaces a dyn_cast with a cast as an instruction cannot be
used by a non-instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229057 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:14:05 +00:00
Chandler Carruth 2640fd5bae [unroll] Replace a linear time check for no uses with a constant time
check.

Also hoist this into the enqueue process as it is faster even than
testing the worklist set, we should just directly filter these out much
like we filter out constants and such.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229056 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 04:06:08 +00:00
Chandler Carruth 6a12276573 [unroll] Rather than an operand set, use a setvector for the worklist.
We don't just want to handle duplicate operands within an instruction,
but also duplicates across operands of different instructions. I should
have gone straight to this, but I had convinced myself that it wasn't
going to be necessary briefly. I've come to my senses after chatting
more with Nick, and am now happier here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229054 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 03:57:40 +00:00
Chandler Carruth 29e00cf519 [unroll] Extract the code to enqueue operansd for the worklist in the
unroll analysis into a lambda and call it. That's much simpler than
duplicating all the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229053 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 03:49:41 +00:00
Chandler Carruth 76908cba94 [unroll] Use a small set to de-duplicate operands prior to putting them
into the worklist. This avoids allocating lots of worklist memory for
them when there are large numbers of repeated operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229052 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 03:48:38 +00:00
Chandler Carruth 595a99573a [unroll] Make the unroll cost analysis terminate deterministically and
reasonably quickly.

I don't have a reduced test case, but for a version of FFMPEG, this
makes the loop unroller start finishing at all (after over 15 minutes of
running, it hadn't terminated for me, no idea if it was a true infloop
or just exponential work).

The key thing here is to check the DeadInstructions set when pulling
things off the worklist. Without this, we would re-walk the user list of
already dead instructions again and again and again. Consider phi nodes
with many, many operands and other patterns.

The other important aspect of this is that because we would keep
re-visiting instructions that were already known dead, we kept adding
their cost savings to this! This would cause our cost savings to be
*insanely* inflated from this.

While I was here, I also rotated the operand walk out of the worklist
loop to make the code easier to read. There is still work to be done to
minimize worklist traffic because we don't de-duplicate operands. This
means we may add the same instruction onto the worklist 1000s of times
if it shows up in 1000s of operansd to a PHI node for example.

Still, with this patch, the ffmpeg testcase I have finishes quickly and
I can't measure the runtime impact of the unroll analysis any more. I'll
probably try to do a few more cleanups to this code, but not sure how
much cleanup I can justify right now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229038 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 03:40:58 +00:00
Chandler Carruth 8f2faeecdb [unroll] Make range based for loops a bit more explicit and more
readable.

The biggest thing that was causing me problems is recognizing the
references vs. poniters here. I also found that for maps naming the loop
variable as KeyValue helps make it obvious why you don't actually use it
directly. Finally, using 'auto' instead of 'User *' doesn't seem like
a good tradeoff. Much like with the other cases, I like to know its
a pointer, and 'User' is just as long and tells the reader a lot more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229033 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 02:45:17 +00:00