Commit Graph

282 Commits

Author SHA1 Message Date
Kazu Hirata c9fca53af1 [CodeGen, Target] Use pred_empty and succ_empty (NFC) 2021-09-10 11:11:31 -07:00
Guozhi Wei 50b6273145 [MBP] findBestLoopTopHelper should exit if OldTop is not a chain header
Function findBestLoopTopHelper tries to find a new loop top block which can also
fall through to OldTop, but it's impossible if OldTop is not a chain header, so
it should exit immediately.

Differential Revision: https://reviews.llvm.org/D106329
2021-07-28 19:00:45 -07:00
Fangrui Song d8aba75a76 Internalize some cl::opt global variables or move them under namespace llvm 2021-05-07 11:15:43 -07:00
Nicholas Guy cd880442ae [CodeGen][AArch64] Add TargetInstrInfo hook to modify the TailDuplicateSize default threshold
Different targets might handle branch performance differently, so this patch allows for
targets to specify the TailDuplicateSize threshold. Said threshold defines how small a branch
can be and still be duplicated to generate straight-line code instead.
This patch also specifies said override values for the AArch64 subtarget.

Differential Revision: https://reviews.llvm.org/D95631
2021-02-08 13:28:00 +00:00
Kazu Hirata 7bc76fd0ec [CodeGen] Construct SmallVector with iterator ranges (NFC) 2020-12-31 09:39:11 -08:00
Guozhi Wei 687e80be7f [MBP] Add whole chain to BlockFilterSet instead of individual BB
Currently we add individual BB to BlockFilterSet if its frequency satisfies

  LoopFreq / Freq <= LoopToColdBlockRatio

LoopFreq is edge frequency from outside to loop header.
LoopToColdBlockRatio is a command line parameter.

It doesn't make sense since we always layout whole chain, not individual BBs.

It may also cause a tricky problem. Sometimes it is possible that the LoopFreq
of an inner loop is smaller than LoopFreq of outer loop. So a BB can be in
BlockFilterSet of inner loop, but not in BlockFilterSet of outer loop,
like .cold in the test case. So it is added to the chain of inner loop. When
work on the outer loop, .cold is not added to BlockFilterSet, so the edge to
successor .problem is not counted in UnscheduledPredecessors of .problem chain.
But other blocks in the inner loop are added BlockFilterSet, so the whole inner
loop chain can be layout, and markChainSuccessors is called to decrease
UnscheduledPredecessors of following chains. markChainSuccessors calls
markBlockSuccessors for every BB, even it is not in BlockFilterSet, like .cold,
so .problem chain's UnscheduledPredecessors is decreased, but this edge was not
counted on in fillWorkLists, so .problem chain's UnscheduledPredecessors
becomes 0 when it still has an unscheduled predecessor .pred! And it causes
problems in following various successor BB selection algorithms.

Differential Revision: https://reviews.llvm.org/D89088
2020-12-16 15:45:47 -08:00
Guozhi Wei d50d7c37a1 [MBP] Prevent rotating a chain contains entry block
The entry block should always be the first BB in a function.
So we should not rotate a chain contains the entry block.

Differential Revision: https://reviews.llvm.org/D92882
2020-12-14 12:48:55 -08:00
Kazu Hirata ee5b5b7a35 [CodeGen] Use llvm::erase_value (NFC) 2020-12-13 20:05:48 -08:00
Kazu Hirata a553ac9791 [CodeGen] llvm::erase_if (NFC) 2020-12-05 15:44:40 -08:00
Kazu Hirata 68403af007 [MBP] Remove unused declaration shouldPredBlockBeOutlined (NFC)
The function was introduced on Jun 12, 2016 in commit
071d0f1807.  Its definition was removed
on Mar 2, 2017 in commit 1393761e0c.
2020-11-21 23:35:02 -08:00
Han Shen e42f6c0ac0 Revert "[MBP] Add whole chain to BlockFilterSet instead of individual BB"
This reverts commit adfb541501.

This is reverted because it caused an chrome error: https://crbug.com/1140168
2020-10-22 17:31:01 -07:00
Guozhi Wei adfb541501 [MBP] Add whole chain to BlockFilterSet instead of individual BB
Currently we add individual BB to BlockFilterSet if its frequency satisfies

LoopFreq / Freq <= LoopToColdBlockRatio

LoopFreq is edge frequency from outside to loop header.
LoopToColdBlockRatio is a command line parameter.

It doesn't make sense since we always layout whole chain, not individual BBs.

It may also cause a tricky problem. Sometimes it is possible that the LoopFreq
of an inner loop is smaller than LoopFreq of outer loop. So a BB can be in
BlockFilterSet of inner loop, but not in BlockFilterSet of outer loop,
like .cold in the test case. So it is added to the chain of inner loop. When
work on the outer loop, .cold is not added to BlockFilterSet, so the edge to
successor .problem is not counted in UnscheduledPredecessors of .problem chain.
But other blocks in the inner loop are added BlockFilterSet, so the whole inner
loop chain can be layout, and markChainSuccessors is called to decrease
UnscheduledPredecessors of following chains. markChainSuccessors calls
markBlockSuccessors for every BB, even it is not in BlockFilterSet, like .cold,
so .problem chain's UnscheduledPredecessors is decreased, but this edge was not
counted on in fillWorkLists, so .problem chain's UnscheduledPredecessors
becomes 0 when it still has an unscheduled predecessor .pred! And it causes
problems in following various successor BB selection algorithms.

Differential Revision: https://reviews.llvm.org/D89088
2020-10-14 11:55:10 -07:00
Guozhi Wei fd75ad8662 [MBFIWrapper] Add a new function getBlockProfileCount
MBFIWrapper keeps track of block frequencies of newly created blocks and
modified blocks, modified block frequencies should also impact block profile
count. This class doesn't provide interface getBlockProfileCount, users can only
use the underlying MBFI to query profile count, the underlying MBFI doesn't know
the modifications made in MBFIWrapper, so it either provides stale profile count
for modified block or simply crashes on new blocks.

So this patch add function getBlockProfileCount to class MBFIWrapper to handle
new blocks or modified blocks.

Differential Revision: https://reviews.llvm.org/D87802
2020-09-23 09:31:45 -07:00
Fangrui Song 6913812abc Fix some clang-tidy bugprone-argument-comment issues 2020-09-19 20:41:25 -07:00
Guozhi Wei 28759e9fcc [MBP] Use profile count to compute tail dup cost if it is available
Current tail duplication in machine block placement pass uses block frequency
information in cost model. But frequency number has only relative meaning
compared to other basic blocks in the same function. A large frequency number
doesn't mean it is hot and a small frequency number doesn't mean it is cold.

To overcome this problem, this patch uses profile count in cost model if it's
available. So we can tail duplicate real hot basic blocks.

Differential Revision: https://reviews.llvm.org/D83265
2020-07-21 11:18:06 -07:00
Yuanfang Chen 78c69a00a4 [NFC] Clean up uses of MachineModuleInfoWrapperPass 2020-07-01 09:45:05 -07:00
James Y Knight 1978309db1 MachineBasicBlock::updateTerminator now requires an explicit layout successor.
Previously, it tried to infer the correct destination block from the
successor list, but this is a rather tricky propspect, given the
existence of successors that occur mid-block, such as invoke, and
potentially in the future, callbr/INLINEASM_BR. (INLINEASM_BR, in
particular would be problematic, because its successor blocks are not
distinct from "normal" successors, as EHPads are.)

Instead, require the caller to pass in the expected fallthrough
successor explicitly. In most callers, the correct block is
immediately clear. But, in MachineBlockPlacement, we do need to record
the original ordering, before starting to reorder blocks.

Unfortunately, the goal of decoupling the behavior of end-of-block
jumps from the successor list has not been fully accomplished in this
patch, as there is currently no other way to determine whether a block
is intended to fall-through, or end as unreachable. Further work is
needed there.

Differential Revision: https://reviews.llvm.org/D79605
2020-06-06 22:30:51 -04:00
Benjamin Kramer 97f92261df [MBP] tuple->pair. NFC.
std::pair has a trivial copy ctor, std::tuple doesn't.
2020-05-02 20:23:34 +02:00
Hongtao Yu 11455a7905 [CodeGen] Allow partial tail duplication in Machine Block Placement.
Summary: A count profile may affect tail duplication's heuristic causing a block to be duplicated in only a part of its predecessors. This is not allowed in the Machine Block Placement pass where an assert will go off. I'm removing the assert and making the optimization bail out when such case happens.

Reviewers: wenlei, davidxl, Carrot

Reviewed By: Carrot

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77748
2020-04-11 12:20:31 -07:00
Hiroshi Yamauchi c3417592c8 Revert "Include static prof data when collecting loop BBs"
This reverts commit 129c911efa.

Due to an internal benchmark regression.
2020-03-24 09:41:16 -07:00
Bill Wendling 129c911efa Include static prof data when collecting loop BBs
Summary:
If the programmer adds static profile data to a branch---i.e. uses
"__builtin_expect()" or similar---then we should honor it. Otherwise,
"__builtin_expect()" is ignored in crucial situations. So we trust that
the programmer knows what they're doing until proven wrong.

Subscribers: hiraditya, JDevlieghere, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74809
2020-02-19 11:33:48 -08:00
Guozhi Wei 369d086d78 [MBP] Partial tail duplication into hot predecessors
Current tail duplication embedded in MBP duplicates a BB into all or none of its predecessors without too much cost analysis. So sometimes it is duplicated into cold predecessors, and in other cases it may miss the duplication into hot predecessors.

This patch improves tail duplication in 3 aspects:

  A successor can be duplicated into part of its predecessors.
  A more fine-grained benefit analysis, combined with 1, now a successor is duplicated into hot predecessors only.
  If a successor can't be duplicated into one predecessor, it doesn't impact the duplication into other predecessors.

Differential Revision: https://reviews.llvm.org/D73387
2020-02-12 15:22:33 -08:00
Hiroshi Yamauchi ac8da31a0f [PGO][PGSO] Handle MBFIWrapper
Some code gen passes use MBFIWrapper to keep track of the frequency of new
blocks. This was not taken into account and could lead to incorrect frequencies
as MBFI silently returns zero frequency for unknown/new blocks.

Add a variant for MBFIWrapper in the PGSO query interface.

Depends on D73494.
2020-01-31 09:36:55 -08:00
Hiroshi Yamauchi 2c03c899d5 [MBFI] Move BranchFolding::MBFIWrapper to its own files. NFC.
Summary:
To avoid header file circular dependency issues in passing updated MBFI (in
MBFIWrapper) to the interface of profile guided size optimizations.

A prep step for (and split off of) D73381.

Reviewers: davidxl

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73494
2020-01-28 10:58:46 -08:00
Krzysztof Parzyszek 020041d99b Update spelling of {analyze,insert,remove}Branch in strings and comments
These names have been changed from CamelCase to camelCase, but there were
many places (comments mostly) that still used the old names.

This change is NFC.
2020-01-21 10:15:38 -06:00
Hiroshi Yamauchi d9ae493937 [PGO][PGSO] Instrument the code gen / target passes.
Summary:
Split off of D67120.

Add the profile guided size optimization instrumentation / queries in the code
gen or target passes. This doesn't enable the size optimizations in those passes
yet as they are currently disabled in shouldOptimizeForSize (for non-IR pass
queries).

A second try after reverted D71072.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71149
2019-12-09 12:42:59 -08:00
Hiroshi Yamauchi 2eb30fafa5 Revert "[PGO][PGSO] Instrument the code gen / target passes."
This reverts commit 9a0b5e1407.

This seems to break buildbots.
2019-12-06 12:17:32 -08:00
Hiroshi Yamauchi 9a0b5e1407 [PGO][PGSO] Instrument the code gen / target passes.
Summary:
Split off of D67120.

Add the profile guided size optimization instrumentation / queries in the code
gen or target passes. This doesn't enable the size optimizations in those passes
yet as they are currently disabled in shouldOptimizeForSize (for non-IR pass
queries).

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71072
2019-12-06 10:43:39 -08:00
Guozhi Wei 72942459d0 [MBP] Avoid tail duplication if it can't bring benefit
Current tail duplication integrated in bb layout is designed to increase the fallthrough from a BB's predecessor to its successor, but we have observed cases that duplication doesn't increase fallthrough, or it brings too much size overhead.

To overcome these two issues in function canTailDuplicateUnplacedPreds I add two checks:

  make sure there is at least one duplication in current work set.
  the number of duplication should not exceed the number of successors.

The modification in hasBetterLayoutPredecessor fixes a bug that potential predecessor must be at the bottom of a chain.

Differential Revision: https://reviews.llvm.org/D64376
2019-12-06 09:53:53 -08:00
Reid Kleckner 05da2fe521 Sink all InitializePasses.h includes
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.

I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
  recompiles    touches affected_files  header
  342380        95      3604    llvm/include/llvm/ADT/STLExtras.h
  314730        234     1345    llvm/include/llvm/InitializePasses.h
  307036        118     2602    llvm/include/llvm/ADT/APInt.h
  213049        59      3611    llvm/include/llvm/Support/MathExtras.h
  170422        47      3626    llvm/include/llvm/Support/Compiler.h
  162225        45      3605    llvm/include/llvm/ADT/Optional.h
  158319        63      2513    llvm/include/llvm/ADT/Triple.h
  140322        39      3598    llvm/include/llvm/ADT/StringRef.h
  137647        59      2333    llvm/include/llvm/Support/Error.h
  131619        73      1803    llvm/include/llvm/Support/FileSystem.h

Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.

Reviewers: bkramer, asbirlea, bollu, jdoerfert

Differential Revision: https://reviews.llvm.org/D70211
2019-11-13 16:34:37 -08:00
Reid Kleckner 67cfa79c01 Revert [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
This reverts r371177 (git commit f879c68755)

It caused PR43566 by removing empty, address-taken MachineBasicBlocks.
Such blocks may have references from blockaddress or other operands, and
need more consideration to be removed.

See the PR for a test case to use when relanding.

llvm-svn: 373805
2019-10-04 22:24:21 +00:00
Yuanfang Chen cc382cf727 [NewPM] Port MachineModuleInfo to the new pass manager.
Existing clients are converted to use MachineModuleInfoWrapperPass. The
new interface is for defining a new pass manager API in CodeGen.

Reviewers: fedor.sergeev, philip.pfaffe, chandlerc, arsenm

Reviewed By: arsenm, fedor.sergeev

Differential Revision: https://reviews.llvm.org/D64183

llvm-svn: 373240
2019-09-30 17:54:50 +00:00
Guillaume Chatelet 18f805a7ea [Alignment][NFC] Remove unneeded llvm:: scoping on Align types
llvm-svn: 373081
2019-09-27 12:54:21 +00:00
Guillaume Chatelet d4c4671aa7 [Alignment][NFC] Remove LogAlignment functions
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: arsenm, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, MaskRay, atanasyan, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67620

llvm-svn: 372231
2019-09-18 15:49:49 +00:00
Guillaume Chatelet 3729b17cff [Alignment][NFC] Use llvm::Align for TargetLowering::getPrefLoopAlignment
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Reviewed By: courbet

Subscribers: wuzish, arsenm, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, MaskRay, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67386

llvm-svn: 371511
2019-09-10 12:00:43 +00:00
Kang Zhang f879c68755 [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
Summary:

Fix a bug of not update the jump table and recommit it again.

In `block-placement` pass, it will create some patterns for unconditional we can do the simple early retrun.
But the `early-ret` pass is before `block-placement`, we don't want to run it again.
This patch is to do the simple early return to optimize the blocks at the last of `block-placement`.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D63972

llvm-svn: 371177
2019-09-06 08:16:18 +00:00
Guillaume Chatelet aff45e4b23 [LLVM][Alignment] Make functions using log of alignment explicit
Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:

 - `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
 - `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
 - `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,

Reviewers: lattner, thegameg, courbet

Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65945

llvm-svn: 371045
2019-09-05 10:00:22 +00:00
Jordan Rupprecht f9f81289e6 Revert [MBP] Disable aggressive loop rotate in plain mode
This reverts r369664 (git commit 51f48295cb)

It causes many benchmark regressions, internally and in llvm's benchmark suite.

llvm-svn: 370398
2019-08-29 19:03:58 +00:00
Jinsong Ji 7f536bcf22 Revert "[CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks"
This reverts commit b3d258fc44.

@skatkov is reporting crash in D63972#1646303
Contacted @ZhangKang, and revert the commit on behalf of him.

llvm-svn: 370069
2019-08-27 14:59:08 +00:00
Guozhi Wei 51f48295cb [MBP] Disable aggressive loop rotate in plain mode
Patch https://reviews.llvm.org/D43256 introduced more aggressive loop layout optimization which depends on profile information. If profile information is not available, the statically estimated profile information(generated by BranchProbabilityInfo.cpp) is used. If user program doesn't behave as BranchProbabilityInfo.cpp expected, the layout may be worse.

To be conservative this patch restores the original layout algorithm in plain mode. But user can still try the aggressive layout optimization with -force-precise-rotation-cost=true.

Differential Revision: https://reviews.llvm.org/D65673

llvm-svn: 369664
2019-08-22 16:21:32 +00:00
Kang Zhang b3d258fc44 [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
Summary:

Fix a bug of preducessors.

In `block-placement` pass, it will create some patterns for unconditional we can do the simple early retrun.
But the `early-ret` pass is before `block-placement`, we don't want to run it again.
This patch is to do the simple early return to optimize the blocks at the last of `block-placement`.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D63972

llvm-svn: 369191
2019-08-17 14:37:05 +00:00
Florian Hahn 403e85cbc5 Revert [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
This reverts r368997 (git commit 2a903c0b67)

It looks like this commit adds invalid predecessors to MBBs. The example
below fails the verifier after MachineBlockPlacement (run llc
-verify-machineinstrs):

@global.4 = external constant i8*

declare i32 @zot(...)

define i16* @snork.67() personality i8* bitcast (i32 (...)* @zot to i8*) {
bb:
  invoke void undef()
          to label %bb5 unwind label %bb4

bb4:                                              ; preds = %bb
  %tmp = landingpad { i8*, i32 }
          catch i8* null
  unreachable

bb5:                                              ; preds = %bb
  %tmp6 = load i32, i32* null, align 4
  %tmp7 = icmp eq i32 %tmp6, 0
  br i1 %tmp7, label %bb14, label %bb8

bb8:                                              ; preds = %bb11, %bb5
  invoke void undef()
          to label %bb9 unwind label %bb11

bb9:                                              ; preds = %bb8
  %tmp10 = invoke i16* undef()
          to label %bb14 unwind label %bb11

bb11:                                             ; preds = %bb9, %bb8
  %tmp12 = landingpad { i8*, i32 }
          cleanup
          catch i8* bitcast (i8** @global.4 to i8*)
  %tmp13 = icmp ult i64 undef, undef
  br i1 %tmp13, label %bb8, label %bb14

bb14:                                             ; preds = %bb11, %bb9, %bb5
  %tmp15 = phi i16* [ null, %bb5 ], [ null, %bb11 ], [ %tmp10, %bb9 ]
  ret i16* %tmp15
}

llvm-svn: 369104
2019-08-16 13:19:29 +00:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
Kang Zhang 2a903c0b67 [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
Summary:

This patch has trigger a bug of r368339, and the r368339 has been reverted, So upstream this patch again.

In `block-placement` pass, it will create some patterns for unconditional we can do the simple early retrun.
But the `early-ret` pass is before `block-placement`, we don't want to run it again.
This patch is to do the simple early return to optimize the blocks at the last of `block-placement`.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D63972

llvm-svn: 368997
2019-08-15 13:05:16 +00:00
Hans Wennborg a45f301f7a Revert r368339 "[MBP] Disable aggressive loop rotate in plain mode"
It caused assertions to fire when building Chromium:

  lib/CodeGen/LiveDebugValues.cpp:331: bool
  {anonymous}::LiveDebugValues::OpenRangesSet::empty() const: Assertion
  `Vars.empty() == VarLocs.empty() && "open ranges are inconsistent"' failed.

See https://crbug.com/992871#c3 for how to reproduce.

> Patch https://reviews.llvm.org/D43256 introduced more aggressive loop layout optimization which depends on profile information. If profile information is not available, the statically estimated profile information(generated by BranchProbabilityInfo.cpp) is used. If user program doesn't behave as BranchProbabilityInfo.cpp expected, the layout may be worse.
>
> To be conservative this patch restores the original layout algorithm in plain mode. But user can still try the aggressive layout optimization with -force-precise-rotation-cost=true.
>
> Differential Revision: https://reviews.llvm.org/D65673

llvm-svn: 368579
2019-08-12 14:23:13 +00:00
Kang Zhang 489efc68a5 Revert r368565: [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
llvm-svn: 368574
2019-08-12 14:00:31 +00:00
Kang Zhang 342fb0db6d [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks
Summary:

In `block-placement` pass, it will create some patterns for unconditional we can do the simple early retrun.
But the `early-ret` pass is before `block-placement`, we don't want to run it again.
This patch is to do the simple early return to optimize the blocks at the last of `block-placement`.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D63972

llvm-svn: 368565
2019-08-12 13:15:31 +00:00
Hans Wennborg 5b96d4655c Revert r368509 "[CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks"
> In `block-placement` pass, it will create some patterns for unconditional we can do the simple early retrun.
> But the `early-ret` pass is before `block-placement`, we don't want to run it again.
> This patch is to do the simple early return to optimize the blocks at the last of `block-placement`.
>
> Reviewed By: efriedma
>
> Differential Revision: https://reviews.llvm.org/D63972

This also revertes follow-ups r368514 and r368532.

llvm-svn: 368560
2019-08-12 12:43:51 +00:00
Kang Zhang b1a62d168f [NFC][CodeGen] Use while loop instead for loop in MachineBlockPlacement::optimizeBranches()
This will pass EXPENSIVE check.

llvm-svn: 368532
2019-08-11 12:58:50 +00:00
Kang Zhang 555f7495df [NFC][CodeGen] Modify the PI++ to ++PI in MachineBlockPlacement::optimizeBranches()
llvm-svn: 368514
2019-08-10 16:23:17 +00:00