Commit Graph

137 Commits

Author SHA1 Message Date
Andrew Kaylor 50271f787e Add opt-bisect support to additional passes that can be skipped
Differential Revision: http://reviews.llvm.org/D19882

llvm-svn: 268457
2016-05-03 22:32:30 +00:00
Mehdi Amini b550cb1750 [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
Duncan P. N. Exon Smith da68cbc4ad IR: RF_IgnoreMissingValues => RF_IgnoreMissingLocals, NFC
Clarify what this RemapFlag actually means.

  - Change the flag name to match its intended behaviour.
  - Clearly document that it's not supposed to affect globals.
  - Add a host of FIXMEs to indicate how to fix the behaviour to match
    the intent of the flag.

RF_IgnoreMissingLocals should only affect the behaviour of
RemapInstruction for function-local operands; namely, for operands of
type Argument, Instruction, and BasicBlock.  Currently, it is *only*
passed into RemapInstruction calls (and the transitive MapValue calls
that it makes).

When I split Metadata from Value I didn't understand the flag, and I
used it in a bunch of places for "global" metadata.

This commit doesn't have any functionality change, but prepares to
cleanup MapMetadata and MapValue.

llvm-svn: 265628
2016-04-07 00:26:43 +00:00
Sanjoy Das 2eac48de9e Return StringRef instead of a naked char*; NFC
llvm-svn: 262989
2016-03-09 02:34:19 +00:00
Sanjoy Das f13900f8ac [IRCE] Reflow comments; NFC
llvm-svn: 262988
2016-03-09 02:34:15 +00:00
Chandler Carruth 31088a9d58 [LPM] Factor all of the loop analysis usage updates into a common helper
routine.

We were getting this wrong in small ways and generally being very
inconsistent about it across loop passes. Instead, let's have a common
place where we do this. One minor downside is that this will require
some analyses like SCEV in more places than they are strictly needed.
However, this seems benign as these analyses are complete no-ops, and
without this consistency we can in many cases end up with the legacy
pass manager scheduling deciding to split up a loop pass pipeline in
order to run the function analysis half-way through. It is very, very
annoying to fix these without just being very pedantic across the board.

The only loop passes I've not updated here are ones that use
AU.setPreservesAll() such as IVUsers (an analysis) and the pass printer.
They seemed less relevant.

With this patch, almost all of the problems in PR24804 around loop pass
pipelines are fixed. The one remaining issue is that we run simplify-cfg
and instcombine in the middle of the loop pass pipeline. We've recently
added some loop variants of these passes that would seem substantially
cleaner to use, but this at least gets us much closer to the previous
state. Notably, the seven loop pass managers is down to three.

I've not updated the loop passes using LoopAccessAnalysis because that
analysis hasn't been fully wired into LoopSimplify/LCSSA, and it isn't
clear that those transforms want to support those forms anyways. They
all run late anyways, so this is harmless. Similarly, LSR is left alone
because it already carefully manages its forms and doesn't need to get
fused into a single loop pass manager with a bunch of other loop passes.

LoopReroll didn't use loop simplified form previously, and I've updated
the test case to match the trivially different output.

Finally, I've also factored all the pass initialization for the passes
that use this technique as well, so that should be done regularly and
reliably.

Thanks to James for the help reviewing and thinking about this stuff,
and Ben for help thinking about it as well!

Differential Revision: http://reviews.llvm.org/D17435

llvm-svn: 261316
2016-02-19 10:45:18 +00:00
Duncan P. N. Exon Smith 3a9c9e3dcd Scalar: Remove some implicit ilist iterator conversions, NFC
Remove some of the implicit ilist iterator conversions in
LLVMScalarOpts.  More to go.

llvm-svn: 250197
2015-10-13 18:26:00 +00:00
Sanjoy Das da0d79e0a0 [IRCE] Add INITIALIZE_PASS_DEPENDENCY invocations.
IRCE was just using INITIALIZE_PASS(), which is incorrect.

llvm-svn: 247122
2015-09-09 03:47:18 +00:00
Chandler Carruth 2f1fd1658f [PM] Port ScalarEvolution to the new pass manager.
This change makes ScalarEvolution a stand-alone object and just produces
one from a pass as needed. Making this work well requires making the
object movable, using references instead of overwritten pointers in
a number of places, and other refactorings.

I've also wired it up to the new pass manager and added a RUN line to
a test to exercise it under the new pass manager. This includes basic
printing support much like with other analyses.

But there is a big and somewhat scary change here. Prior to this patch
ScalarEvolution was never *actually* invalidated!!! Re-running the pass
just re-wired up the various other analyses and didn't remove any of the
existing entries in the SCEV caches or clear out anything at all. This
might seem OK as everything in SCEV that can uses ValueHandles to track
updates to the values that serve as SCEV keys. However, this still means
that as we ran SCEV over each function in the module, we kept
accumulating more and more SCEVs into the cache. At the end, we would
have a SCEV cache with every value that we ever needed a SCEV for in the
entire module!!! Yowzers. The releaseMemory routine would dump all of
this, but that isn't realy called during normal runs of the pipeline as
far as I can see.

To make matters worse, there *is* actually a key that we don't update
with value handles -- there is a map keyed off of Loop*s. Because
LoopInfo *does* release its memory from run to run, it is entirely
possible to run SCEV over one function, then over another function, and
then lookup a Loop* from the second function but find an entry inserted
for the first function! Ouch.

To make matters still worse, there are plenty of updates that *don't*
trip a value handle. It seems incredibly unlikely that today GVN or
another pass that invalidates SCEV can update values in *just* such
a way that a subsequent run of SCEV will incorrectly find lookups in
a cache, but it is theoretically possible and would be a nightmare to
debug.

With this refactoring, I've fixed all this by actually destroying and
recreating the ScalarEvolution object from run to run. Technically, this
could increase the amount of malloc traffic we see, but then again it is
also technically correct. ;] I don't actually think we're suffering from
tons of malloc traffic from SCEV because if we were, the fact that we
never clear the memory would seem more likely to have come up as an
actual problem before now. So, I've made the simple fix here. If in fact
there are serious issues with too much allocation and deallocation,
I can work on a clever fix that preserves the allocations (while
clearing the data) between each run, but I'd prefer to do that kind of
optimization with a test case / benchmark that shows why we need such
cleverness (and that can test that we actually make it faster). It's
possible that this will make some things faster by making the SCEV
caches have higher locality (due to being significantly smaller) so
until there is a clear benchmark, I think the simple change is best.

Differential Revision: http://reviews.llvm.org/D12063

llvm-svn: 245193
2015-08-17 02:08:17 +00:00
Cong Hou ab23bfbc0e Create a wrapper pass for BranchProbabilityInfo.
This new wrapper pass is useful when we want to do branch probability analysis conditionally (e.g. only in PGO mode) but don't want to add one more pass dependence.

http://reviews.llvm.org/D11241

llvm-svn: 242349
2015-07-15 22:48:29 +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
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
Sanjoy Das 45dc94a856 [IRCE] Fix how IRCE checks for no-sign-overflow.
IRCE requires the induction variables it handles to not sign-overflow.
The current scheme of checking if sext({X,+,S}) == {sext(X),+,sext(S)}
fails when SCEV simplifies sext(X) too.  After this change we //also//
check no-signed-wrap by looking at the flags set on the SCEVAddRecExpr.

llvm-svn: 233102
2015-03-24 19:29:22 +00:00
Sanjoy Das 337d46b36f [IRCE] Fix a regression introduced in r232444.
IRCE should not try to eliminate range checks that check an induction
variable against a loop-varying length.

llvm-svn: 233101
2015-03-24 19:29:18 +00:00
Benjamin Kramer 799003bf8c Re-sort includes with sort-includes.py and insert raw_ostream.h where it's used.
llvm-svn: 232998
2015-03-23 19:32:43 +00:00
David Blaikie c4dfa63928 Fix GCC -Wparentheses warning (& reformat now that the precedence is fixed)
Benign warning (clang deliberately suppresses this case) but does
regularly produce bad formatting, so it's nice to fix/reformat.

llvm-svn: 232508
2015-03-17 17:48:24 +00:00
Reid Kleckner 0b16859805 Use an underlying enum type of unsigned to silence a -Wmicrosoft warning about being unable to put (unsigned)-1 into the default underyling type of int
llvm-svn: 232498
2015-03-17 16:50:20 +00:00
Sanjoy Das 9c1bfae604 [IRCE] Add a -irce-print-range-checks option.
-irce-print-range-checks prints out the set of range checks recognized
by IRCE.

llvm-svn: 232451
2015-03-17 01:40:22 +00:00
Sanjoy Das 7a0b7f5996 [IRCE] Add comments, NFC.
This change adds some comments that justify why a potentially
overflowing operation is safe.

llvm-svn: 232445
2015-03-17 00:42:16 +00:00
Sanjoy Das e2cde6f195 [IRCE] Support half-range checks.
This change to IRCE gets it to recognize "half" range checks.  Half
range checks are range checks that only either check if the index is
`slt` some positive integer ("length") or if the index is `sge` `0`.

The range solver does not try to be clever / aggressive about solving
half-range checks -- it transforms "I < L" to "0 <= I < L" and "0 <= I"
to "0 <= I < INT_SMAX".  This is safe, but not always optimal.

llvm-svn: 232444
2015-03-17 00:42:13 +00:00
Mehdi Amini a28d91d81b DataLayout is mandatory, update the API to reflect it with references.
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.

This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.

I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.

I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.

Test Plan:

Reviewers: echristo

Subscribers: llvm-commits

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231740
2015-03-10 02:37:25 +00:00
Sanjoy Das e91665de39 IRCE: only touch loops that have been shown to have a high
backedge-taken count in profiliing data.

llvm-svn: 230619
2015-02-26 08:56:04 +00:00
Sanjoy Das e75ed92630 IRCE: generalize to handle loops with decreasing induction variables.
IRCE can now split the iteration space for loops like:

   for (i = n; i >= 0; i--)
     a[i + k] = 42; // bounds check on access

llvm-svn: 230618
2015-02-26 08:19:31 +00:00
Sanjoy Das 48c75814a5 IRCE: print newline after printing an InductiveRangeCheck.
llvm-svn: 230607
2015-02-26 04:03:31 +00:00
Sanjoy Das 95c476db94 IRCE: generalize InductiveRangeCheck::computeSafeIterationSpace to
work with a non-canonical induction variable.

This is currently a non-functional change because we only ever call
computeSafeIterationSpace on a canonical induction variable; but the
generalization will be useful in a later commit.

llvm-svn: 230151
2015-02-21 22:20:22 +00:00
Sanjoy Das 7fc60da2f5 IRCE: use SCEVs instead of llvm::Value's for intermediate
calculations.  Semantically non-functional change.

This gets rid of some of the SCEV -> Value -> SCEV round tripping and
the Construct(SMin|SMax)Of and MaybeSimplify helper routines.

llvm-svn: 230150
2015-02-21 22:07:32 +00:00
Benjamin Kramer 970eac40bf Make helper functions/classes/globals static. NFC.
llvm-svn: 228410
2015-02-06 17:51:54 +00:00
Benjamin Kramer 39f76acb5c IRCE: Demote template to ArrayRef and SmallVector to array.
NFC.

llvm-svn: 228398
2015-02-06 14:43:49 +00:00
Sanjoy Das dcf2651043 Teach IRCE to look at branch weights when recognizing range checks
Splitting a loop to make range checks redundant is profitable only if
the range check "never" fails. Make this fact a part of recognizing a
range check -- a branch is a range check only if it is expected to
pass (via branch_weights metadata).

Differential Revision: http://reviews.llvm.org/D7192

llvm-svn: 227249
2015-01-27 21:38:12 +00:00
Sanjoy Das 351db05308 [NFC] Introduce a 'struct Range' for IRCE
Use the struct instead of a std::pair<Value *, Value *>.  This makes a
Range an obviously immutable object, and we can now assert that a
range is well-typed (Begin->getType() == End->getType()) on its
construction.

llvm-svn: 226804
2015-01-22 09:32:02 +00:00
Sanjoy Das d1fb13ce4c Fix crashes in IRCE caused by mismatched types
There are places where the inductive range check elimination pass
depends on two llvm::Values or llvm::SCEVs to be of the same
llvm::Type when they do not need to be. This patch relaxes those
restrictions (by bailing out of the optimization if the types
mismatch), and adds test cases to trigger those paths.

These issues were found by bootstrapping clang with IRCE running in
the -O3 pass ordering.

Differential Revision: http://reviews.llvm.org/D7082

llvm-svn: 226793
2015-01-22 08:29:18 +00:00
Chandler Carruth 691addc25f [PM] Now that LoopInfo isn't in the Pass type hierarchy, it is much
cleaner to derive from the generic base.

Thise removes a ton of boiler plate code and somewhat strange and
pointless indirections. It also remove a bunch of the previously needed
friend declarations. To fully remove these, I also lifted the verify
logic into the generic LoopInfoBase, which seems good anyways -- it is
generic and useful logic even for the machine side.

llvm-svn: 226385
2015-01-18 01:25:51 +00:00
Chandler Carruth 4f8f307c77 [PM] Split the LoopInfo object apart from the legacy pass, creating
a LoopInfoWrapperPass to wire the object up to the legacy pass manager.

This switches all the clients of LoopInfo over and paves the way to port
LoopInfo to the new pass manager. No functionality change is intended
with this iteration.

llvm-svn: 226373
2015-01-17 14:16:18 +00:00
Sanjoy Das a1837a342d Add a new pass "inductive range check elimination"
IRCE eliminates range checks of the form

  0 <= A * I + B < Length

by splitting a loop's iteration space into three segments in a way
that the check is completely redundant in the middle segment.  As an
example, IRCE will convert

  len = < known positive >
  for (i = 0; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }

to

  len = < known positive >
  limit = smin(n, len)
  // no first segment
  for (i = 0; i < limit; i++) {
    if (0 <= i && i < len) { // this check is fully redundant
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }
  for (i = limit; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }


IRCE can deal with multiple range checks in the same loop (it takes
the intersection of the ranges that will make each of them redundant
individually).

Currently IRCE does not do any profitability analysis.  That is a
TODO.

Please note that the status of this pass is *experimental*, and it is
not part of any default pass pipeline.  Having said that, I will love
to get feedback and general input from people interested in trying
this out.

This pass was originally r226201.  It was reverted because it used C++
features not supported by MSVC 2012.

Differential Revision: http://reviews.llvm.org/D6693

llvm-svn: 226238
2015-01-16 01:03:22 +00:00
Sanjoy Das 7f62ac8e4d Revert r226201 (Add a new pass "inductive range check elimination")
The change used C++11 features not supported by MSVC 2012.  I will fix
the change to use things supported MSVC 2012 and recommit shortly.

llvm-svn: 226216
2015-01-15 22:18:10 +00:00
David Majnemer f1f72c9e43 InductiveRangeCheckElimination: Remove extra ';'
This silences a GCC warning.

llvm-svn: 226215
2015-01-15 21:55:16 +00:00
Sanjoy Das 7059e2959d Add a new pass "inductive range check elimination"
IRCE eliminates range checks of the form

  0 <= A * I + B < Length

by splitting a loop's iteration space into three segments in a way
that the check is completely redundant in the middle segment.  As an
example, IRCE will convert

  len = < known positive >
  for (i = 0; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }

to

  len = < known positive >
  limit = smin(n, len)
  // no first segment
  for (i = 0; i < limit; i++) {
    if (0 <= i && i < len) { // this check is fully redundant
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }
  for (i = limit; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }


IRCE can deal with multiple range checks in the same loop (it takes
the intersection of the ranges that will make each of them redundant
individually).

Currently IRCE does not do any profitability analysis.  That is a
TODO.

Please note that the status of this pass is *experimental*, and it is
not part of any default pass pipeline.  Having said that, I will love
to get feedback and general input from people interested in trying
this out.

Differential Revision: http://reviews.llvm.org/D6693

llvm-svn: 226201
2015-01-15 20:45:46 +00:00