Commit Graph

29 Commits

Author SHA1 Message Date
Sanjay Patel 33ec5dbe35 less indent; NFCI
llvm-svn: 252643
2015-11-10 20:09:02 +00:00
Sanjay Patel 766589efdc add 'MustReduceDepth' as an objective/cost-metric for the MachineCombiner
This is one of the problems noted in PR25016:
https://llvm.org/bugs/show_bug.cgi?id=25016
and:
http://lists.llvm.org/pipermail/llvm-dev/2015-October/090998.html

The spilling problem is independent and not addressed by this patch.

The MachineCombiner was doing reassociations that don't improve or even worsen the critical path. 
This is caused by inclusion of the "slack" factor when calculating the critical path of the original
code sequence. If we don't add that, then we have a more conservative cost comparison of the old code
sequence vs. a new sequence. The more liberal calculation must be preserved, however, for the AArch64
MULADD patterns because benchmark regressions were observed without that.

The two failing test cases now have identical asm that does what we want:
a + b + c + d ---> (a + b) + (c + d)

Differential Revision: http://reviews.llvm.org/D13417

llvm-svn: 252616
2015-11-10 16:48:53 +00:00
Sanjay Patel 387e66e79f replace MachineCombinerPattern namespace and enum with enum class; NFCI
Also, remove an enum hack where enum values were used as indexes into an array.

We may want to make this a real class to allow pattern-based queries/customization (D13417).

llvm-svn: 252196
2015-11-05 19:34:57 +00:00
Hans Wennborg 083ca9bb32 Fix Clang-tidy modernize-use-nullptr warnings in source directories and generated files; other minor cleanups.
Patch by Eugene Zelenko!

Differential Revision: http://reviews.llvm.org/D13321

llvm-svn: 249482
2015-10-06 23:24:35 +00:00
Sanjay Patel acd4baefca include equal sign in debug equations; NFC
llvm-svn: 249248
2015-10-03 20:45:01 +00:00
Sanjay Patel 74ca312666 fix minsize detection: minsize attribute implies optimizing for size
llvm-svn: 244604
2015-08-11 14:31:14 +00:00
Hal Finkel 17caf326e5 [MachineCombiner] Don't use the opcode-only form of computeInstrLatency
In r242277, I updated the MachineCombiner to work with itineraries, but I
missed a call that is scheduling-model-only (the opcode-only form of
computeInstrLatency). Using the form that takes an MI* allows this to work with
itineraries (and should be NFC for subtargets with scheduling models).

llvm-svn: 244020
2015-08-05 07:45:28 +00:00
Sanjay Patel 924879ad2c wrap OptSize and MinSize attributes for easier and consistent access (NFCI)
Create wrapper methods in the Function class for the OptimizeForSize and MinSize
attributes. We want to hide the logic of "or'ing" them together when optimizing
just for size (-Os).

Currently, we are not consistent about this and rely on a front-end to always set
OptimizeForSize (-Os) if MinSize (-Oz) is on. Thus, there are 18 FIXME changes here
that should be added as follow-on patches with regression tests.

This patch is NFC-intended: it just replaces existing direct accesses of the attributes
by the equivalent wrapper call.

Differential Revision: http://reviews.llvm.org/D11734

llvm-svn: 243994
2015-08-04 15:49:57 +00:00
Hal Finkel e0fa8f2c86 [MachineCombiner] Work with itineraries
MachineCombiner predicated its use of scheduling-based metrics on
hasInstrSchedModel(), but useful conclusions can be drawn from pipeline
itineraries as well. Almost all of the logic (except for resource tracking in
preservesResourceLen) can be used if we have an itinerary, so enable it in that
case as well.

This will be used by the PowerPC backend in an upcoming commit.

llvm-svn: 242277
2015-07-15 08:22:23 +00:00
Alexander Kornienko f00654e31b Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Sanjay Patel e79b43a01f [x86] generalize reassociation optimization in machine combiner to 2 instructions
Currently ( D10321, http://reviews.llvm.org/rL239486 ), we can use the machine combiner pass
to reassociate the following sequence to reduce the critical path:

A = ? op ?
B = A op X
C = B op Y
-->
A = ? op ?
B = X op Y
C = A op B

'op' is currently limited to x86 AVX scalar FP adds (with fast-math on), but in theory, it could
be any associative math/logic op (see TODO in code comment).

This patch generalizes the pattern match to ignore the instruction that defines 'A'. So instead of
a sequence of 3 adds, we now only need to find 2 dependent adds and decide if it's worth
reassociating them.

This generalization has a compile-time cost because we can now match more instruction sequences
and we rely more heavily on the machine combiner to discard sequences where reassociation doesn't
improve the critical path.

For example, in the new test case:

A = M div N
B = A add X
C = B add Y

We'll match 2 reassociation patterns, but this transform doesn't reduce the critical path:

A = M div N
B = A add Y
C = B add X

We need the combiner to reject that pattern but select this:

A = M div N
B = X add Y
C = B add A

Differential Revision: http://reviews.llvm.org/D10460

llvm-svn: 240361
2015-06-23 00:39:40 +00:00
Sanjay Patel cfe0393b82 name change: hasPattern() -> getMachineCombinerPatterns() ; NFC
This was suggested as part of D10460, but it's independent of
any functional change.

llvm-svn: 240192
2015-06-19 23:21:42 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Sanjay Patel 5714998484 hoist loop-invariant; NFCI
llvm-svn: 239681
2015-06-13 15:33:15 +00:00
Sanjay Patel 85924e5bf3 remove unnecessary casts; NFCI
llvm-svn: 239678
2015-06-13 15:06:33 +00:00
Sanjay Patel ccb8d5cc57 punctuation policing; NFC
llvm-svn: 239484
2015-06-10 19:52:58 +00:00
Sanjay Patel a32fadd14a fix typo in comment; NFC
llvm-svn: 239478
2015-06-10 17:08:12 +00:00
Sanjay Patel f911484051 fix typo in comment; NFC
llvm-svn: 237962
2015-05-21 21:29:13 +00:00
Sanjay Patel f69f4e42ce use range-based for-loops; NFCI
llvm-svn: 237918
2015-05-21 17:43:26 +00:00
Duncan P. N. Exon Smith 70eb9c5ae5 CodeGen: 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)

Also, add `Function::getFnStackAlignment()`, and canonicalize:

getAttributes().getStackAlignment(AttributeSet::FunctionIndex)
  => getFnStackAlignment()

llvm-svn: 229208
2015-02-14 01:44:41 +00:00
Sanjay Patel b1ca4e48d4 remove function names from comments; NFC
llvm-svn: 227256
2015-01-27 22:26:56 +00:00
Sanjay Patel 6b280777b7 fix typos; NFC
llvm-svn: 227253
2015-01-27 22:16:52 +00:00
Eric Christopher 3d4276f053 The subtarget is cached on the MachineFunction. Access it directly.
llvm-svn: 227173
2015-01-27 07:31:29 +00:00
Pete Cooper 1175945710 Change MCSchedModel to be a struct of statically initialized data.
This removes static initializers from the backends which generate this data, and also makes this struct match the other Tablegen generated structs in behaviour

Reviewed by Andy Trick and Chandler C

llvm-svn: 216919
2014-09-02 17:43:54 +00:00
Gerolf Hoflehner fe2c11ffd6 [MachineCombiner] Removal of dangling DBG_VALUES after combining [20598]
This is a cleaner solution to the problem described in r215431.
When instructions are combined a dangling DBG_VALUE is removed.
This resolves bug 20598.

llvm-svn: 215587
2014-08-13 22:07:36 +00:00
Gerolf Hoflehner 97c383bc36 MachineCombiner Pass for selecting faster instruction sequence on AArch64
Re-commit of r214832,r21469 with a work-around that
avoids the previous problem with gcc build compilers

The work-around is to use SmallVector instead of ArrayRef
of basic blocks in preservesResourceLen()/MachineCombiner.cpp

llvm-svn: 215151
2014-08-07 21:40:58 +00:00
Eric Christopher d913448b38 Remove the TargetMachine forwards for TargetSubtargetInfo based
information and update all callers. No functional change.

llvm-svn: 214781
2014-08-04 21:25:23 +00:00
Saleem Abdulrasool befa21532c CodeGen: silence a warning
GCC 4.8.2 objects to the tautological condition in the assert as the unsigned
value is guaranteed to be >= 0.  Simplify the assertion by dropping the
tautological condition.

llvm-svn: 214671
2014-08-03 23:00:38 +00:00
Gerolf Hoflehner 5e1207e54c MachineCombiner Pass for selecting faster instruction
sequence -  target independent framework

 When the DAGcombiner selects instruction sequences
 it could increase the critical path or resource len.

 For example, on arm64 there are multiply-accumulate instructions (madd,
 msub). If e.g. the equivalent  multiply-add sequence is not on the
 crictial path it makes sense to select it instead of  the combined,
 single accumulate instruction (madd/msub). The reason is that the
 conversion from add+mul to the madd could lengthen the critical path
 by the latency of the multiply.

 But the DAGCombiner would always combine and select the madd/msub
 instruction.

 This patch uses machine trace metrics to estimate critical path length
 and resource length of an original instruction sequence vs a combined
 instruction sequence and picks the faster code based on its estimates.

 This patch only commits the target independent framework that evaluates
 and selects code sequences. The machine instruction combiner is turned
 off for all targets and expected to evolve over time by gradually
 handling DAGCombiner pattern in the target specific code.

 This framework lays the groundwork for fixing
 rdar://16319955

llvm-svn: 214666
2014-08-03 21:35:39 +00:00