Commit Graph

22 Commits

Author SHA1 Message Date
Chandler Carruth
aeef83c6af Switch TargetTransformInfo from an immutable analysis pass that requires
a TargetMachine to construct (and thus isn't always available), to an
analysis group that supports layered implementations much like
AliasAnalysis does. This is a pretty massive change, with a few parts
that I was unable to easily separate (sorry), so I'll walk through it.

The first step of this conversion was to make TargetTransformInfo an
analysis group, and to sink the nonce implementations in
ScalarTargetTransformInfo and VectorTargetTranformInfo into
a NoTargetTransformInfo pass. This allows other passes to add a hard
requirement on TTI, and assume they will always get at least on
implementation.

The TargetTransformInfo analysis group leverages the delegation chaining
trick that AliasAnalysis uses, where the base class for the analysis
group delegates to the previous analysis *pass*, allowing all but tho
NoFoo analysis passes to only implement the parts of the interfaces they
support. It also introduces a new trick where each pass in the group
retains a pointer to the top-most pass that has been initialized. This
allows passes to implement one API in terms of another API and benefit
when some other pass above them in the stack has more precise results
for the second API.

The second step of this conversion is to create a pass that implements
the TargetTransformInfo analysis using the target-independent
abstractions in the code generator. This replaces the
ScalarTargetTransformImpl and VectorTargetTransformImpl classes in
lib/Target with a single pass in lib/CodeGen called
BasicTargetTransformInfo. This class actually provides most of the TTI
functionality, basing it upon the TargetLowering abstraction and other
information in the target independent code generator.

The third step of the conversion adds support to all TargetMachines to
register custom analysis passes. This allows building those passes with
access to TargetLowering or other target-specific classes, and it also
allows each target to customize the set of analysis passes desired in
the pass manager. The baseline LLVMTargetMachine implements this
interface to add the BasicTTI pass to the pass manager, and all of the
tools that want to support target-aware TTI passes call this routine on
whatever target machine they end up with to add the appropriate passes.

The fourth step of the conversion created target-specific TTI analysis
passes for the X86 and ARM backends. These passes contain the custom
logic that was previously in their extensions of the
ScalarTargetTransformInfo and VectorTargetTransformInfo interfaces.
I separated them into their own file, as now all of the interface bits
are private and they just expose a function to create the pass itself.
Then I extended these target machines to set up a custom set of analysis
passes, first adding BasicTTI as a fallback, and then adding their
customized TTI implementations.

The fourth step required logic that was shared between the target
independent layer and the specific targets to move to a different
interface, as they no longer derive from each other. As a consequence,
a helper functions were added to TargetLowering representing the common
logic needed both in the target implementation and the codegen
implementation of the TTI pass. While technically this is the only
change that could have been committed separately, it would have been
a nightmare to extract.

The final step of the conversion was just to delete all the old
boilerplate. This got rid of the ScalarTargetTransformInfo and
VectorTargetTransformInfo classes, all of the support in all of the
targets for producing instances of them, and all of the support in the
tools for manually constructing a pass based around them.

Now that TTI is a relatively normal analysis group, two things become
straightforward. First, we can sink it into lib/Analysis which is a more
natural layer for it to live. Second, clients of this interface can
depend on it *always* being available which will simplify their code and
behavior. These (and other) simplifications will follow in subsequent
commits, this one is clearly big enough.

Finally, I'm very aware that much of the comments and documentation
needs to be updated. As soon as I had this working, and plausibly well
commented, I wanted to get it committed and in front of the build bots.
I'll be doing a few passes over documentation later if it sticks.

Commits to update DragonEgg and Clang will be made presently.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171681 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 01:37:14 +00:00
Tom Stellard
a52c3acc14 Add a MachinePostDominator pass
This is used in the AMDIL and R600 backends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164029 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-17 14:08:37 +00:00
Nadav Rotem
c05d30601c Add a new optimization pass: Stack Coloring, that merges disjoint static allocations (allocas). Allocas are known to be
disjoint if they are marked by disjoint lifetime markers (@llvm.lifetime.XXX intrinsics).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163299 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 09:17:37 +00:00
Jakob Stoklund Olesen
33242fd3ed Add an experimental early if-conversion pass, off by default.
This pass performs if-conversion on SSA form machine code by
speculatively executing both sides of the branch and using a cmov
instruction to select the result. This can help lower the number of
branch mispredictions on architectures like x86 that don't have
predicable instructions.

The current implementation is very aggressive, and causes regressions on
mosts tests. It needs good heuristics that have yet to be implemented.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159694 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-04 00:09:54 +00:00
Jakob Stoklund Olesen
312244747c Remove the RenderMachineFunction HTML output pass.
I don't think anyone has been using this functionality for a while, and
it is getting in the way of refactoring now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158876 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-20 23:47:58 +00:00
Jakob Stoklund Olesen
05ec712e7f Reintroduce VirtRegRewriter.
OK, not really. We don't want to reintroduce the old rewriter hacks.

This patch extracts virtual register rewriting as a separate pass that
runs after the register allocator. This is possible now that
CodeGen/Passes.cpp can configure the full optimizing register allocator
pipeline.

The rewriter pass uses register assignments in VirtRegMap to rewrite
virtual registers to physical registers, and it inserts kill flags based
on live intervals.

These finalization steps are the same for the optimizing register
allocators: RABasic, RAGreedy, and PBQP.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158244 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-08 23:44:45 +00:00
Bob Wilson
6e1b812850 Add an insertPass API to TargetPassConfig. <rdar://problem/11498613>
Besides adding the new insertPass function, this patch uses it to
enhance the existing -print-machineinstrs so that the MachineInstrs
after a specific pass can be printed.

Patch by Bin Zeng!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157655 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 00:17:12 +00:00
Andrew Trick
1dd8c8560d Codegen pass definition cleanup. No functionality.
Moving toward a uniform style of pass definition to allow easier target configuration.
Globally declare Pass ID.
Globally declare pass initializer.
Use INITIALIZE_PASS consistently.
Add a call to the initializer from CodeGen.cpp.
Remove redundant "createPass" functions and "getPassName" methods.

While cleaning up declarations, cleaned up comments (sorry for large diff).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150100 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 21:23:13 +00:00
Andrew Trick
61f1e3db43 Move pass configuration out of pass constructors: BranchFolderPass
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150095 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 21:22:48 +00:00
Andrew Trick
7461334084 Make TargetPassConfig an ImmutablePass so CodeGenPasses can query options
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149752 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-04 02:56:45 +00:00
Andrew Trick
42b7a71dc7 Renamed MachineScheduler to ScheduleTopDownLive.
Responding to code review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148290 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-17 06:55:03 +00:00
Andrew Trick
96f678f2d7 Added the MachineSchedulerPass skeleton.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148105 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-13 06:30:30 +00:00
Lang Hames
bae56b4c21 Kill off the LoopSplitter. It's not being used or maintained.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145897 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-06 01:57:59 +00:00
NAKAMURA Takumi
569561c7ee Prune more RALinScan. RALinScan was also here!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144487 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-13 01:33:10 +00:00
Chandler Carruth
37efc9fe42 Begin collecting some of the statistics for block placement discussed on
the mailing list. Suggestions for other statistics to collect would be
awesome. =]

Currently these are implemented as a separate pass guarded by a separate
flag. I'm not thrilled by that, but I wanted to be able to collect the
statistics for the old code placement as well as the new in order to
have a point of comparison. I'm planning on folding them into the single
pass if / when there is only one pass of interest.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143537 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-02 07:17:12 +00:00
Chandler Carruth
db35087d21 Implement a block placement pass based on the branch probability and
block frequency analyses. This differs substantially from the existing
block-placement pass in LLVM:

1) It operates on the Machine-IR in the CodeGen layer. This exposes much
   more (and more precise) information and opportunities. Also, the
   results are more stable due to fewer transforms ocurring after the
   pass runs.
2) It uses the generalized probability and frequency analyses. These can
   model static heuristics, code annotation derived heuristics as well
   as eventual profile loading. By basing the optimization on the
   analysis interface it can work from any (or a combination) of these
   inputs.
3) It uses a more aggressive algorithm, both building chains from tho
   bottom up to maximize benefit, and using an SCC-based walk to layout
   chains of blocks in a profitable ordering without O(N^2) iterations
   which the old pass involves.

The pass is currently gated behind a flag, and not enabled by default
because it still needs to grow some important features. Most notably, it
needs to support loop aligning and careful layout of loop structures
much as done by hand currently in CodePlacementOpt. Once it supports
these, and has sufficient testing and quality tuning, it should replace
both of these passes.

Thanks to Nick Lewycky and Richard Smith for help authoring & debugging
this, and to Jakob, Andy, Eric, Jim, and probably a few others I'm
forgetting for reviewing and answering all my questions. Writing
a backend pass is *sooo* much better now than it used to be. =D

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142641 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-21 06:46:38 +00:00
Jakub Staszak
f55c1c8588 Rename BlockFrequency to BlockFrequencyInfo and MachineBlockFrequency to
MachineBlockFrequencyInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135937 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-25 19:25:40 +00:00
Evan Cheng
f10711fb8c Remove the experimental (and unused) pre-ra splitting pass. Greedy regalloc can split live ranges.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133962 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-27 23:40:45 +00:00
Rafael Espindola
5b220213bf There is only one register coalescer. Merge it into the base class and
remove the analysis group.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133899 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-26 22:34:10 +00:00
Jakob Stoklund Olesen
bb7b23f5b7 Stub out a new LiveDebugVariables pass.
This analysis is going to run immediately after LiveIntervals. It will stay
alive during register allocation and keep track of user variables mentioned in
DBG_VALUE instructions.

When the register allocator is moving values between registers and the stack, it
is very hard to keep track of DBG_VALUE instructions. We usually get it wrong.
This analysis maintains a data structure that makes it easy to update DBG_VALUE
instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120385 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 02:17:10 +00:00
Owen Anderson
081c34b725 Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19 17:21:58 +00:00
Owen Anderson
78b152470d Add initialization routines for CodeGen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115949 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 18:41:20 +00:00