Commit Graph

250 Commits

Author SHA1 Message Date
Matthias Braun f84547c6e0 LiveIntervalAnalysis: Remove LiveVariables requirement
This requirement was a huge hack to keep LiveVariables alive because it
was optionally used by TwoAddressInstructionPass and PHIElimination.
However we have AnalysisUsage::addUsedIfAvailable() which we can use in
those passes.

This re-applies r260806 with LiveVariables manually added to PowerPC to
hopefully not break the stage 2 bots this time.

llvm-svn: 267954
2016-04-28 23:42:51 +00:00
Andrew Kaylor 289bd5f684 Add optimization bisect opt-in calls for PowerPC passes
Differential Revision: http://reviews.llvm.org/D19554

llvm-svn: 267769
2016-04-27 19:39:32 +00:00
Ehsan Amiri 4701a91e59 [PPC] Enable transformations in PPCPassConfig::addIRPasses at O2
http://reviews.llvm.org/D18562

A large number of testcases has been modified so they pass after this test.
One testcase is deleted, because I realized even after undoing the original
change that was committed with this testcase, the testcase still passes. So
I removed it. The change to one other testcase (test/CodeGen/PowerPC/pr25802.ll)
is an arbitrary change to keep it passing. Given the original intention of the
testcase, and the fact that fixing it will require some time to change the testcase,
we concluded that this quick change will be enough.

llvm-svn: 265683
2016-04-07 15:30:55 +00:00
Hal Finkel fc35391f2b [PowerPC] Add a late MI-level pass for QPX load/splat simplification
Chapter 3 of the QPX manual states that, "Scalar floating-point load
instructions, defined in the Power ISA, cause a replication of the source data
across all elements of the target register." Thus, if we have a load followed
by a QPX splat (from the first lane), the splat is redundant. This adds a late
MI-level pass to remove the redundant splats in some of these cases
(specifically when both occur in the same basic block).

This optimization is scheduled just prior to post-RA scheduling. It can't happen
before anything that might replace the load with some already-computed quantity
(i.e. store-to-load forwarding).

llvm-svn: 265047
2016-03-31 20:39:41 +00:00
Nirav Dave 8dd66e5753 Remove HasFnAttribute guards to getFnAttribute calls
These checks are redundant and can be removed

Reviewers: hans

Subscribers: llvm-commits, mzolotukhin

Differential Revision: http://reviews.llvm.org/D18564

llvm-svn: 264872
2016-03-30 15:41:12 +00:00
Adam Nemet 9d9cb274ea [PPCLoopDataPrefetch] Move pass to Transforms/Scalar/LoopDataPrefetch. NFC
This patch is part of the work to make PPCLoopDataPrefetch
target-independent
(http://thread.gmane.org/gmane.comp.compilers.llvm.devel/92758).

Obviously the pass still only used from PPC at this point.  Subsequent
patches will start driving this from ARM64 as well.

Due to the previous patch most lines should show up as moved lines.

llvm-svn: 261265
2016-02-18 21:38:19 +00:00
Petar Jovanovic 280f7101e8 [Power PC] llvm soft float support for ppc32
This is the second in a set of patches for soft float support for ppc32,
it enables soft float operations.

Patch by Strahinja Petrovic.

Differential Revision: http://reviews.llvm.org/D13700

llvm-svn: 255516
2015-12-14 17:57:33 +00:00
Kit Barton a1c712fae5 [PPC64] Convert bool literals to i32
Convert i1 values to i32 values if they should be allocated in GPRs instead of CRs.

Phabricator: http://reviews.llvm.org/D14064
llvm-svn: 254942
2015-12-07 20:50:29 +00:00
Bill Schmidt 34af5e1c76 [PowerPC] Add an MI SSA peephole pass.
This patch adds a pass for doing PowerPC peephole optimizations at the
MI level while the code is still in SSA form.  This allows for easy
modifications to the instructions while depending on a subsequent pass
of DCE.  Both passes are very fast due to the characteristics of SSA.

At this time, the only peepholes added are for cleaning up various
redundancies involving the XXPERMDI instruction.  However, I would
expect this will be a useful place to add more peepholes for
inefficiencies generated during instruction selection.  The pass is
placed after VSX swap optimization, as it is best to let that pass
remove unnecessary swaps before performing any remaining clean-ups.

The utility of these clean-ups are demonstrated by changes to four
existing test cases, all of which now have tighter expected code
generation.  I've also added Eric Schweiz's bugpoint-reduced test from
PR25157, for which we now generate tight code.  One other test started
failing for me, and I've fixed it
(test/Transforms/PlaceSafepoints/finite-loops.ll) as well; this is not
related to my changes, and I'm not sure why it works before and not
after.  The problem is that the CHECK-NOT: of "statepoint" from test1
fails because of the "statepoint" in test2, and so forth.  Adding a
CHECK-LABEL in between keeps the different occurrences of that string
properly scoped.

llvm-svn: 252651
2015-11-10 21:38:26 +00:00
NAKAMURA Takumi 0a7d0ad95f Untabify.
llvm-svn: 248264
2015-09-22 11:15:07 +00:00
NAKAMURA Takumi 84965031a7 Reformat comment lines.
llvm-svn: 248262
2015-09-22 11:14:12 +00:00
NAKAMURA Takumi 70ad98aca4 Reformat.
llvm-svn: 248261
2015-09-22 11:13:55 +00:00
Eric Christopher a4e5d3cf8e constify the Function parameter to the TTI creation callback and
propagate to all callers/users/etc.

llvm-svn: 247864
2015-09-16 23:38:13 +00:00
Hal Finkel 5d36b230b5 [PowerPC] Use the MachineCombiner to reassociate fadd/fmul
This is a direct port of the code from the X86 backend (r239486/r240361), which
uses the MachineCombiner to reassociate (floating-point) adds/muls to increase
ILP, to the PowerPC backend. The rationale is the same.

There is a lot of copy-and-paste here between the X86 code and the PowerPC
code, and we should extract at least some of this into CodeGen somewhere.
However, I don't want to do that until this code is enhanced to handle FMAs as
well. After that, we'll be in a better position to extract the common parts.

llvm-svn: 242279
2015-07-15 08:23:05 +00:00
Hal Finkel cbf08925ef [PowerPC] Make use of the TargetRecip system
r238842 added the TargetRecip system for controlling use of reciprocal
estimates for sqrt and division using a set of parameters that can be set by
the frontend. Clang now supports a sophisticated -mrecip option, and this will
allow that option to effectively control the relevant code-generation
functionality of the PPC backend.

llvm-svn: 241985
2015-07-12 02:33:57 +00:00
Daniel Sanders c81f450f1a Clean up redundant copies of Triple objects. NFC
Summary:

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10382

llvm-svn: 239823
2015-06-16 15:44:21 +00:00
Daniel Sanders 335487ad87 Replace string GNU Triples with llvm::Triple in TargetMachine::getTargetTriple(). NFC.
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10381

llvm-svn: 239815
2015-06-16 13:15:50 +00:00
Daniel Sanders 3e5de88dac Replace string GNU Triples with llvm::Triple in TargetMachine. NFC.
Summary:
For the moment, TargetMachine::getTargetTriple() still returns a StringRef.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: ted, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10362

llvm-svn: 239554
2015-06-11 19:41:26 +00:00
Daniel Sanders a73f1fdb19 Replace string GNU Triples with llvm::Triple in MCSubtargetInfo and create*MCSubtargetInfo(). NFC.
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rafael

Reviewed By: rafael

Subscribers: rafael, ted, jfb, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10311

llvm-svn: 239467
2015-06-10 12:11:26 +00:00
Hal Finkel 8340de142c [PowerPC] Add extra r2 read deps on @toc@l relocations
If some commits are happy, and some commits are sad, this is a sad commit. It
is sad because it restricts instruction scheduling to work around a binutils
linker bug, and moreover, one that may never be fixed. On 2012-05-21, GCC was
updated not to produce code triggering this bug, and now we'll do the same...

When resolving an address using the ELF ABI TOC pointer, two relocations are
generally required: one for the high part and one for the low part. Only
the high part generally explicitly depends on r2 (the TOC pointer). And, so,
we might produce code like this:

.Ltmp526:
        addis 3, 2, .LC12@toc@ha
.Ltmp1628:
        std 2, 40(1)
        ld 5, 0(27)
        ld 2, 8(27)
        ld 11, 16(27)
        ld 3, .LC12@toc@l(3)
        rldicl 4, 4, 0, 32
        mtctr 5
        bctrl
        ld 2, 40(1)

And there is nothing wrong with this code, as such, but there is a linker bug
in binutils (https://sourceware.org/bugzilla/show_bug.cgi?id=18414) that will
misoptimize this code sequence to this:
        nop
        std     r2,40(r1)
        ld      r5,0(r27)
        ld      r2,8(r27)
        ld      r11,16(r27)
        ld      r3,-32472(r2)
        clrldi  r4,r4,32
        mtctr   r5
        bctrl
        ld      r2,40(r1)
because the linker does not know (and does not check) that the value in r2
changed in between the instruction using the .LC12@toc@ha (TOC-relative)
relocation and the instruction using the .LC12@toc@l(3) relocation.
Because it finds these instructions using the relocations (and not by
scanning the instructions), it has been asserted that there is no good way
to detect the change of r2 in between. As a result, this bug may never be
fixed (i.e. it may become part of the definition of the ABI). GCC was
updated to add extra dependencies on r2 to instructions using the @toc@l
relocations to avoid this problem, and we'll do the same here.

This is done as a separate pass because:
 1. These extra r2 dependencies are not really properties of the
    instructions, but rather due to a linker bug, and maybe one day we'll be
    able to get rid of them when targeting linkers without this bug (and,
    thus, keeping the logic centralized here will make that
    straightforward).
 2. There are ISel-level peephole optimizations that propagate the @toc@l
    relocations to some user instructions, and so the exta dependencies do
    not apply only to a fixed set of instructions (without undesirable
    definition replication).

The test case was reduced with the help of bugpoint, with minimal cleaning. I'm
looking forward to our upcoming MI serialization support, and with that, much
better tests can be created.

llvm-svn: 237556
2015-05-18 06:25:59 +00:00
Bill Schmidt fe723b9a6d [PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations
This patch adds a new SSA MI pass that runs on little-endian PPC64
code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors
without alignment constraints are accomplished for little-endian using
lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional
xxswapd instructions hurts performance in comparison with big-endian
code, but they are necessary in the general case to support correct
semantics.

However, the general case does not apply to most vector code. Many
vector instructions are lane-insensitive; they do not "care" which
lanes the parallel computations are performed within, provided that
the resulting data is stored into the correct locations. Thus this
pass looks for computations that perform only lane-insensitive
operations, and remove the unnecessary swaps from loads and stores in
such computations.

Future improvements will allow computations using certain
lane-sensitive operations to also be optimized in this manner, by
modifying the lane-sensitive operations to account for the permuted
order of the lanes. However, this patch only adds the infrastructure
to permit this; no lane-sensitive operations are optimized at this
time.

This code is heavily exercised by the various vectorizing applications
in the projects/test-suite tree. For the time being, I have only added
one simple test case to demonstrate what the pass is doing. Although
it is quite simple, it provides coverage for much of the code,
including the special case handling of copies and subreg-to-reg
operations feeding the swaps. I plan to add additional tests in the
future as I fill in more of the "special handling" code.

Two existing tests were affected, because they expected the swaps to
be present, but they are now removed.

llvm-svn: 235910
2015-04-27 19:57:34 +00:00
Eric Christopher ed1042b97c Add computeFSAdditions to the function based subtarget creation
for PPC due to some unfortunate default setting via TargetMachine
creation. I've added a FIXME on how this can be unraveled in the
backend and a test to make sure we successfully legalize 64-bit things
if we say we're 64-bits.

llvm-svn: 233239
2015-03-26 00:50:23 +00:00
Eric Christopher 83eb13c967 Remove the bare getSubtargetImpl call from the PPC port. As part
of this add a test that shows we can generate code with
for functions that differ by subtarget feature.

llvm-svn: 232882
2015-03-21 03:36:02 +00:00
Mehdi Amini 93e1ea167e Move the DataLayout to the generic TargetMachine, making it mandatory.
Summary:
I don't know why every singled backend had to redeclare its own DataLayout.
There was a virtual getDataLayout() on the common base TargetMachine, the
default implementation returned nullptr. It was not clear from this that
we could assume at call site that a DataLayout will be available with
each Target.

Now getDataLayout() is no longer virtual and return a pointer to the
DataLayout member of the common base TargetMachine. I plan to turn it into
a reference in a future patch.

The only backend that didn't have a DataLayout previsouly was the CPPBackend.
It now initializes the default DataLayout. This commit is NFC for all the
other backends.

Test Plan: clang+llvm ninja check-all

Reviewers: echristo

Subscribers: jfb, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8243

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231987
2015-03-12 00:07:24 +00:00
Hal Finkel e5aaf3f2cd [PowerPC] Loop Data Prefetching for the BG/Q
The IBM BG/Q supercomputer's A2 cores have a hardware prefetching unit, the
L1P, but it does not prefetch directly into the A2's L1 cache. Instead, it
prefetches into its own L1P buffer, and the latency to access that buffer is
significantly higher than that to the L1 cache (although smaller than the
latency to the L2 cache). As a result, especially when multiple hardware
threads are not actively busy, explicitly prefetching data into the L1 cache is
advantageous.

I've been using this pass out-of-tree for data prefetching on the BG/Q for well
over a year, and it has worked quite well. It is enabled by default only for
the BG/Q, but can be enabled for other cores as well via a command-line option.

Eventually, we might want to add some TTI interfaces and move this into
Transforms/Scalar (there is nothing particularly target dependent about it,
although only machines like the BG/Q will benefit from its simplistic
strategy).

llvm-svn: 229966
2015-02-20 05:08:21 +00:00
Eric Christopher fee6aaf683 Move ABI handling and 64-bitness to the PowerPC target machine.
This required changing how the computation of the ABI is handled
and how some of the checks for ABI/target are done.

llvm-svn: 229471
2015-02-17 06:45:15 +00:00
Duncan P. N. Exon Smith 5bedaf934f PowerPC: Canonicalize access to function attributes, NFC
Canonicalize access to function attributes to use the simpler API.

getAttributes().getAttribute(AttributeSet::FunctionIndex, Kind)
  => getFnAttribute(Kind)

getAttributes().hasAttribute(AttributeSet::FunctionIndex, Kind)
  => hasFnAttribute(Kind)

llvm-svn: 229224
2015-02-14 02:54:07 +00:00
Chandler Carruth 30d69c2e36 [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".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00
Bill Schmidt 82f1c775a0 [PowerPC] Fix reverted patch r227976 to avoid register assignment issues
See full discussion in http://reviews.llvm.org/D7491.

We now hide the add-immediate and call instructions together in a
separate pseudo-op, which is tagged to define GPR3 and clobber the
call-killed registers.  The PPCTLSDynamicCall pass prior to RA now
expands this op into the two separate addi and call ops, with explicit
definitions of GPR3 on both instructions, and explicit clobbers on the
call instruction.  The pass is now marked as requiring and preserving
the LiveIntervals and SlotIndexes analyses, and fixes these up after
the replacement sequences are introduced.

Self-hosting has been verified on LE P8 and BE P7 with various
optimization levels, etc.  It has also been verified with the
--no-tls-optimize flag workaround removed.

llvm-svn: 228725
2015-02-10 19:09:05 +00:00
Hal Finkel 0d2a1515d5 Revert "r227976 - [PowerPC] Yet another approach to __tls_get_addr" and related fixups
Unfortunately, even with the workaround of disabling the linker TLS
optimizations in Clang restored (which has already been done), this still
breaks self-hosting on my P7 machine (-O3 -DNDEBUG -mcpu=native).

Bill is currently working on an alternate implementation to address the TLS
issue in a way that also fully elides the linker bug (which, unfortunately,
this approach did not fully), so I'm reverting this now.

llvm-svn: 228460
2015-02-06 23:07:40 +00:00
Hal Finkel c9dd02066c [PowerPC] Prepare loops for pre-increment loads/stores
PowerPC supports pre-increment load/store instructions (except for Altivec/VSX
vector load/stores). Using these on embedded cores can be very important, but
most loops are not naturally set up to use them. We can often change that,
however, by placing loops into a non-canonical form. Generically, this means
transforming loops like this:

  for (int i = 0; i < n; ++i)
    array[i] = c;

to look like this:

  T *p = array[-1];
  for (int i = 0; i < n; ++i)
    *++p = c;

the key point is that addresses accessed are pulled into dedicated PHIs and
"pre-decremented" in the loop preheader. This allows the use of pre-increment
load/store instructions without loop peeling.

A target-specific late IR-level pass (running post-LSR), PPCLoopPreIncPrep, is
introduced to perform this transformation. I've used this code out-of-tree for
generating code for the PPC A2 for over a year. Somewhat to my surprise,
running the test suite + externals on a P7 with this transformation enabled
showed no performance regressions, and one speedup:

External/SPEC/CINT2006/483.xalancbmk/483.xalancbmk
	-2.32514% +/- 1.03736%

So I'm going to enable it on everything for now. I was surprised by this
because, on the POWER cores, these pre-increment load/store instructions are
cracked (and, thus, harder to schedule effectively). But seeing no regressions,
and feeling that it is generally easier to split instructions apart late than
it is to combine them late, this might be the better approach regardless.

In the future, we might want to integrate this functionality into LSR (but
currently LSR does not create new PHI nodes, so (for that and other reasons)
significant work would need to be done).

llvm-svn: 228328
2015-02-05 18:43:00 +00:00
Bill Schmidt 685aa8b0c5 [PowerPC] Yet another approach to __tls_get_addr
This patch is a third attempt to properly handle the local-dynamic and
global-dynamic TLS models.

In my original implementation, calls to __tls_get_addr were hidden
from view until the asm-printer phase, at which point the underlying
branch-and-link instruction was created with proper relocations.  This
mostly worked well, but I used some repellent techniques to ensure
that the TLS_GET_ADDR nodes at the SD and MI levels correctly received
input from GPR3 and produced output into GPR3.  This proved to work
badly in the presence of multiple TLS variable accesses, with the
copies to and from GPR3 being scheduled incorrectly and generally
creating havoc.

In r221703, I addressed that problem by representing the calls to
__tls_get_addr as true calls during instruction lowering.  This had
the advantage of removing all of the bad hacks and relying on the
existing call machinery to properly glue the copies in place. It
looked like this was going to be the right way to go.

However, as a side effect of the recent discovery of problems with
linker optimizations for TLS, we discovered cases of suboptimal code
generation with this strategy.  The problem comes when tls_get_addr is
called for the same address, and there is a resulting CSE
opportunity.  It turns out that in such cases MachineCSE will common
the addis/addi instructions that set up the input value to
tls_get_addr, but will not common the calls themselves.  MachineCSE
does not have any machinery to common idempotent calls.  This is
perfectly sensible, since presumably this would be done at the IR
level, and introducing calls in the back end isn't commonplace.  In
any case, we end up with two calls to __tls_get_addr when one would
suffice, and that isn't good.

I presumed that the original design would have allowed commoning of
the machine-specific nodes that hid the __tls_get_addr calls, so as
suggested by Ulrich Weigand, I went back to that design and cleaned it
up so that the copies were properly held together by glue
nodes.  However, it turned out that this didn't work either...the
presence of copies to physical registers kept the machine-specific
nodes from being commoned also.

All of which leads to the design presented here.  This is a return to
the original design, except that no attempt is made to introduce
copies to and from GPR3 during instruction lowering.  Virtual registers
are used until prior to register allocation.  At that point, a special
pass is run that identifies the machine-specific nodes that hide the
tls_get_addr calls and introduces the copies to and from GPR3 around
them.  The register allocator then coalesces these copies away.  With
this design, MachineCSE succeeds in commoning tls_get_addr calls where
possible, and we get nice optimal code generation (better than GCC at
the moment, which does not common these calls).

One additional problem must be dealt with:  After introducing the
mentions of the physical register GPR3, the aggressive anti-dependence
breaker sees opportunities to improve scheduling by selecting a
different register instead.  Flags must be used on the instruction
descriptions to tell the anti-dependence breaker to keep its hands in
its pockets.

One thing missing from the original design was recording a definition
of the link register on the GET_TLS_ADDR nodes.  Doing this was found
to be insufficient to force a stack frame to be created, which led to
looping behavior because two different LR values were stored at the
same address.  This appears to have been an oversight in
PPCFrameLowering::determineFrameLayout(), which is repaired here.

Because MustSaveLR() returns true for calls to builtin_return_address,
this changed the expected behavior of
test/CodeGen/PowerPC/retaddr2.ll, which now stacks a frame but
formerly did not.  I've fixed the test case to reflect this.

There are existing TLS tests to catch regressions; the checks in
test/CodeGen/PowerPC/tls-store2.ll proved to be too restrictive in the
face of instruction scheduling with these changes, so I fixed that
up.

I've added a new test case based on the PrettyStackTrace module that
demonstrated the original problem. This checks that we get correct
code generation and that CSE of the calls to __get_tls_addr has taken
place.

llvm-svn: 227976
2015-02-03 16:16:01 +00:00
Hal Finkel 83d695419c [PowerPC] Remove the PPCVSXCopyCleanup pass
This MI-level pass was necessary when VSX support was first being developed,
specifically, before the ABI code had been updated to use VSX registers for
arguments (the register assignments did not change, in a physical sense, but
the VSX super-registers are now used). Unfortunately, I never went back and
removed this pass after that was done. I believe this code is now effectively
dead.

llvm-svn: 227767
2015-02-01 21:20:58 +00:00
Chandler Carruth 8b04c0d26a [multiversion] Switch all of the targets over to use the
TargetIRAnalysis access path directly rather than implementing getTTI.

This even removes getTTI from the interface. It's more efficient for
each target to just register a precise callback that creates their
specific TTI.

As part of this, all of the targets which are building their subtargets
individually per-function now build their TTI instance with the function
and thus look up the correct subtarget and cache it. NVPTX, R600, and
XCore currently don't leverage this functionality, but its trivial for
them to add it now.

llvm-svn: 227735
2015-02-01 13:20:00 +00:00
Chandler Carruth 93dcdc47db [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

llvm-svn: 227685
2015-01-31 11:17:59 +00:00
Chandler Carruth 705b185f90 [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00
Eric Christopher b1874ebd32 Remove unused function.
llvm-svn: 227624
2015-01-30 22:02:36 +00:00
Eric Christopher 8b7706517c Move DataLayout back to the TargetMachine from TargetSubtargetInfo
derived classes.

Since global data alignment, layout, and mangling is often based on the
DataLayout, move it to the TargetMachine. This ensures that global
data is going to be layed out and mangled consistently if the subtarget
changes on a per function basis. Prior to this all targets(*) have
had subtarget dependent code moved out and onto the TargetMachine.

*One target hasn't been migrated as part of this change: R600. The
R600 port has, as a subtarget feature, the size of pointers and
this affects global data layout. I've currently hacked in a FIXME
to enable progress, but the port needs to be updated to either pass
the 64-bitness to the TargetMachine, or fix the DataLayout to
avoid subtarget dependent features.

llvm-svn: 227113
2015-01-26 19:03:15 +00:00
Hal Finkel e2ab0f17cf [PowerPC] Loosen ELFv1 PPC64 func descriptor loads for indirect calls
Function pointers under PPC64 ELFv1 (which is used on PPC64/Linux on the
POWER7, A2 and earlier cores) are really pointers to a function descriptor, a
structure with three pointers: the actual pointer to the code to which to jump,
the pointer to the TOC needed by the callee, and an environment pointer. We
used to chain these loads, and make them opaque to the rest of the optimizer,
so that they'd always occur directly before the call. This is not necessary,
and in fact, highly suboptimal on embedded cores. Once the function pointer is
known, the loads can be performed ahead of time; in fact, they can be hoisted
out of loops.

Now these function descriptors are almost always generated by the linker, and
thus the contents of the descriptors are invariant. As a result, by default,
we'll mark the associated loads as invariant (allowing them to be hoisted out
of loops). I've added a target feature to turn this off, however, just in case
someone needs that option (constructing an on-stack descriptor, casting it to a
function pointer, and then calling it cannot be well-defined C/C++ code, but I
can imagine some JIT-compilation system doing so).

Consider this simple test:
  $ cat call.c

  typedef void (*fp)();
  void bar(fp x) {
    for (int i = 0; i < 1600000000; ++i)
      x();
  }

  $ cat main.c

  typedef void (*fp)();
  void bar(fp x);
  void foo() {}
  int main() {
    bar(foo);
  }

On the PPC A2 (the BG/Q supercomputer), marking the function-descriptor loads
as invariant brings the execution time down to ~8 seconds from ~32 seconds with
the loads in the loop.

The difference on the POWER7 is smaller. Compiling with:

  gcc -std=c99 -O3 -mcpu=native call.c main.c : ~6 seconds [this is 4.8.2]

  clang -O3 -mcpu=native call.c main.c : ~5.3 seconds

  clang -O3 -mcpu=native call.c main.c -mno-invariant-function-descriptors : ~4 seconds
  (looks like we'd benefit from additional loop unrolling here, as a first
   guess, because this is faster with the extra loads)

The -mno-invariant-function-descriptors will be added to Clang shortly.

llvm-svn: 226207
2015-01-15 21:17:34 +00:00
Chandler Carruth d9903888d9 [cleanup] Re-sort all the #include lines in LLVM using
utils/sort_includes.py.

I clearly haven't done this in a while, so more changed than usual. This
even uncovered a missing include from the InstrProf library that I've
added. No functionality changed here, just mechanical cleanup of the
include order.

llvm-svn: 225974
2015-01-14 11:23:27 +00:00
Matthias Braun 7e37a5f523 [CodeGen] Add print and verify pass after each MachineFunctionPass by default
Previously print+verify passes were added in a very unsystematic way, which is
annoying when debugging as you miss intermediate steps and allows bugs to stay
unnotice when no verification is performed.

To make this change practical I added the possibility to explicitely disable
verification. I used this option on all places where no verification was
performed previously (because alot of places actually don't pass the
MachineVerifier).
In the long term these problems should be fixed properly and verification
enabled after each pass. I'll enable some more verification in subsequent
commits.

This is the 2nd attempt at this after realizing that PassManager::add() may
actually delete the pass.

llvm-svn: 224059
2014-12-11 21:26:47 +00:00
Rafael Espindola 01c73610d0 This reverts commit r224043 and r224042.
check-llvm was failing.

llvm-svn: 224045
2014-12-11 20:03:57 +00:00
Matthias Braun a7c82a9f1d [CodeGen] Add print and verify pass after each MachineFunctionPass by default
Previously print+verify passes were added in a very unsystematic way, which is
annoying when debugging as you miss intermediate steps and allows bugs to stay
unnotice when no verification is performed.

To make this change practical I added the possibility to explicitely disable
verification. I used this option on all places where no verification was
performed previously (because alot of places actually don't pass the
MachineVerifier).
In the long term these problems should be fixed properly and verification
enabled after each pass. I'll enable some more verification in subsequent
commits.

llvm-svn: 224042
2014-12-11 19:42:05 +00:00
Hal Finkel f413be11f0 [PPC] Use SeparateConstOffsetFromGEP
This mirrors r222331, which enabled SeparateConstOffsetFromGEP on AArch64, in
the PowerPC backend. Yields, on a POWER7 machine, a 30% speedup on
SingleSource/Benchmarks/Shootout/nestedloop (this might just be from LICM,
there is a store moved out of the inner loop) and a potential speedup on
MultiSource/Benchmarks/mediabench/mpeg2/mpeg2dec/mpeg2decode. Regardless, it
makes some code look cleaner, and synchronizing the backends in this regard
seems like a generally good thing.

llvm-svn: 222504
2014-11-21 04:35:51 +00:00
Reid Kleckner 357600eab5 Add out of line virtual destructors to all LLVMTargetMachine subclasses
These recently all grew a unique_ptr<TargetLoweringObjectFile> member in
r221878.  When anyone calls a virtual method of a class, clang-cl
requires all virtual methods to be semantically valid. This includes the
implicit virtual destructor, which triggers instantiation of the
unique_ptr destructor, which fails because the type being deleted is
incomplete.

This is just part of the ongoing saga of PR20337, which is affecting
Blink as well. Because the MSVC ABI doesn't have key functions, we end
up referencing the vtable and implicit destructor on any virtual call
through a class. We don't actually end up emitting the dtor, so it'd be
good if we could avoid this unneeded type completion work.

llvm-svn: 222480
2014-11-20 23:37:18 +00:00
Aditya Nandakumar a27193297f This patch changes the ownership of TLOF from TargetLoweringBase to TargetMachine so that different subtargets could share the TLOF effectively
llvm-svn: 221878
2014-11-13 09:26:31 +00:00
Eric Christopher 3faf2f1e02 Add subtarget caches to aarch64, arm, ppc, and x86.
These will make it easier to test further changes to the
code generation and optimization pipelines as those are
moved to subtargets initialized with target feature and
target cpu.

llvm-svn: 219106
2014-10-06 06:45:36 +00:00
Eric Christopher eb6e3bbf47 Now that the optimization level is adjusting the feature string
before we hit the subtarget, remove the constructor parameter.

llvm-svn: 218817
2014-10-01 21:05:35 +00:00
Eric Christopher 36448af7f5 Rework the PPC TargetMachine so that the non-function specific
overrides happen at TargetMachine creation and not on every
subtarget creation.

llvm-svn: 218805
2014-10-01 20:38:26 +00:00
Robin Morisset 2212996936 [Power] Use AtomicExpandPass for fence insertion, and use lwsync where appropriate
Summary:
This patch makes use of AtomicExpandPass in Power for inserting fences around
atomic as part of an effort to remove fence insertion from SelectionDAGBuilder.
As a big bonus, it lets us use sync 1 (lightweight sync, often used by the mnemonic
lwsync) instead of sync 0 (heavyweight sync) in many cases.

I also added a test, as there was no test for the barriers emitted by the Power
backend for atomic loads and stores.

Test Plan: new test + make check-all

Reviewers: jfb

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5180

llvm-svn: 218331
2014-09-23 20:46:49 +00:00