Commit Graph

99 Commits

Author SHA1 Message Date
Alina Sbirlea 5c5cf899ef [MemorySSA] Moving at the end often means before terminator.
Moving accesses in MemorySSA at InsertionPlace::End, when an instruction is
moved into a block, almost always means insert at the end of the block, but
before the block terminator. This matters when the block terminator is a
MemoryAccess itself (an invoke), and the insertion must be done before
the terminator for the update to be correct.

Insert an additional position: InsertionPlace:BeforeTerminator and update
current usages where this applies.

Resolves PR44027.
2019-11-20 17:11:00 -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
Alina Sbirlea 4ae74cc99f [GVNHoist] Preserve AAResults.
Resolves PR38906, PR40898.
2019-11-12 14:10:04 -08:00
Simon Pilgrim 57e8f0b055 GVNHoist - silence static analyzer dyn_cast<> null dereference warning in hasEHOrLoadsOnPath call. NFCI.
The static analyzer is warning about a potential null dereference, but we should be able to use cast<> directly and if not assert will fire for us.

llvm-svn: 375429
2019-10-21 17:15:49 +00:00
Guillaume Chatelet d400d45150 [Alignment][NFC] Remove StoreInst::setAlignment(unsigned)
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, bollu, jdoerfert

Subscribers: hiraditya, asbirlea, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D68268

llvm-svn: 373595
2019-10-03 13:17:21 +00:00
Guillaume Chatelet ab11b9188d [Alignment][NFC] Remove AllocaInst::setAlignment(unsigned)
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: jholewinski, arsenm, jvesely, nhaehnle, eraman, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D68141

llvm-svn: 373207
2019-09-30 13:34:44 +00:00
Guillaume Chatelet 17380227e8 [Alignment][NFC] Remove LoadInst::setAlignment(unsigned)
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, jdoerfert

Subscribers: hiraditya, asbirlea, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D68142

llvm-svn: 373195
2019-09-30 09:37:05 +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
Fangrui Song efd94c56ba Use llvm::stable_sort
While touching the code, simplify if feasible.

llvm-svn: 358996
2019-04-23 14:51:27 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Michael Kruse 978ba61536 Introduce llvm.loop.parallel_accesses and llvm.access.group metadata.
The current llvm.mem.parallel_loop_access metadata has a problem in that
it uses LoopIDs. LoopID unfortunately is not loop identifier. It is
neither unique (there's even a regression test assigning the some LoopID
to multiple loops; can otherwise happen if passes such as LoopVersioning
make copies of entire loops) nor persistent (every time a property is
removed/added from a LoopID's MDNode, it will also receive a new LoopID;
this happens e.g. when calling Loop::setLoopAlreadyUnrolled()).
Since most loop transformation passes change the loop attributes (even
if it just to mark that a loop should not be processed again as
llvm.loop.isvectorized does, for the versioned and unversioned loop),
the parallel access information is lost for any subsequent pass.

This patch unlinks LoopIDs and parallel accesses.
llvm.mem.parallel_loop_access metadata on instruction is replaced by
llvm.access.group metadata. llvm.access.group points to a distinct
MDNode with no operands (avoiding the problem to ever need to add/remove
operands), called "access group". Alternatively, it can point to a list
of access groups. The LoopID then has an attribute
llvm.loop.parallel_accesses with all the access groups that are parallel
(no dependencies carries by this loop).

This intentionally avoid any kind of "ID". Loops that are clones/have
their attributes modifies retain the llvm.loop.parallel_accesses
attribute. Access instructions that a cloned point to the same access
group. It is not necessary for each access to have it's own "ID" MDNode,
but those memory access instructions with the same behavior can be
grouped together.

The behavior of llvm.mem.parallel_loop_access is not changed by this
patch, but should be considered deprecated.

Differential Revision: https://reviews.llvm.org/D52116

llvm-svn: 349725
2018-12-20 04:58:07 +00:00
Chandler Carruth e303c87e19 [TI removal] Make `getTerminator()` return a generic `Instruction`.
This removes the primary remaining API producing `TerminatorInst` which
will reduce the rate at which code is introduced trying to use it and
generally make it much easier to remove the remaining APIs across the
codebase.

Also clean up some of the stragglers that the previous mechanical update
of variables missed.

Users of LLVM and out-of-tree code generally will need to update any
explicit variable types to handle this. Replacing `TerminatorInst` with
`Instruction` (or `auto`) almost always works. Most of these edits were
made in prior commits using the perl one-liner:
```
perl -i -ple 's/TerminatorInst(\b.* = .*getTerminator\(\))/Instruction\1/g'
```

This also my break some rare use cases where people overload for both
`Instruction` and `TerminatorInst`, but these should be easily fixed by
removing the `TerminatorInst` overload.

llvm-svn: 344504
2018-10-15 10:42:50 +00:00
Fangrui Song 0cac726a00 llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)
Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: dblaikie, javed.absar, JDevlieghere, andreadb

Subscribers: MatzeB, sanjoy, arsenm, dschuff, mehdi_amini, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, eraman, aheejin, kbarton, JDevlieghere, javed.absar, gbedwell, jrtc27, mgrang, atanasyan, steven_wu, george.burgess.iv, dexonsmith, kristina, jsji, llvm-commits

Differential Revision: https://reviews.llvm.org/D52573

llvm-svn: 343163
2018-09-27 02:13:45 +00:00
Alexandros Lamprineas 54d56f274c [GVNHoist] computeInsertionPoints() miscalculates IDF
Fix for https://bugs.llvm.org/show_bug.cgi?id=38912.

In GVNHoist::computeInsertionPoints() we iterate over the Value
Numbers and calculate the Iterated Dominance Frontiers without
clearing the IDFBlocks vector first. IDFBlocks ends up accumulating
an insane number of basic blocks, which bloats the compilation time
of SemaChecking.cpp with ubsan enabled.

Differential Revision: https://reviews.llvm.org/D51980

llvm-svn: 342055
2018-09-12 14:28:23 +00:00
Alexandros Lamprineas 484bd13e2d [GVNHoist] Prune out useless CHI insertions
Fix for the out-of-memory error when compiling SemaChecking.cpp
with GVNHoist and ubsan enabled. I've used a cache for inserted
CHIs to avoid excessive memory usage.

Differential Revision: https://reviews.llvm.org/D50323

llvm-svn: 340818
2018-08-28 11:07:54 +00:00
Chandler Carruth 9ae926b973 [IR] Replace `isa<TerminatorInst>` with `isTerminator()`.
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.

All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.

llvm-svn: 340701
2018-08-26 09:51:22 +00:00
Chandler Carruth 96fc1de77d [IR] Begin removal of TerminatorInst by removing successor manipulation.
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.

The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.

Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.

This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

There will be a series of much more mechanical changes following this
one to complete this move.

Differential Revision: https://reviews.llvm.org/D47467

llvm-svn: 340698
2018-08-26 08:41:15 +00:00
Florian Hahn 406f1ff1cd [Local] Make DoesKMove required for combineMetadata.
This patch makes the DoesKMove argument non-optional, to force people
to think about it. Most cases where it is false are either code hoisting
or code sinking, where we pick one instruction from a set of
equal instructions among different code paths.

Reviewers: dberlin, nlopes, efriedma, davide

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D47475

llvm-svn: 340606
2018-08-24 11:40:04 +00:00
Alexandros Lamprineas 592cc78dd8 [GVNHoist] safeToHoistLdSt allows illegal hoisting
Bug fix for PR36787. When reasoning if it's safe to hoist a load we
want to make sure that the defining memory access dominates the new
insertion point of the hoisted instruction. safeToHoistLdSt calls
firstInBB(InsertionPoint,DefiningAccess) which returns false if
InsertionPoint == DefiningAccess, and therefore it falsely thinks
it's safe to hoist.

Differential Revision: https://reviews.llvm.org/D49555

llvm-svn: 337674
2018-07-23 09:42:35 +00:00
David Blaikie 31b98d2e99 Move Analysis/Utils/Local.h back to Transforms
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)

llvm-svn: 333954
2018-06-04 21:23:21 +00:00
Vedant Kumar 5a0872c2b7 [STLExtras] Add size() for ranges, and remove distance()
r332057 introduced distance() for ranges. Based on post-commit feedback,
this renames distance() to size(). The new size() is also only enabled
when the operation is O(1).

Differential Revision: https://reviews.llvm.org/D46976

llvm-svn: 332551
2018-05-16 23:20:42 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Vedant Kumar e0b5f86b30 [STLExtras] Add distance() for ranges, pred_size(), and succ_size()
This commit adds a wrapper for std::distance() which works with ranges.
As it would be a common case to write `distance(predecessors(BB))`, this
also introduces `pred_size()` and `succ_size()` helpers to make that
easier to write.

Differential Revision: https://reviews.llvm.org/D46668

llvm-svn: 332057
2018-05-10 23:01:54 +00:00
Mandeep Singh Grang 636d94db3b [Transforms] Change std::sort to llvm::sort in response to r327219
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.

Reviewers: kcc, pcc, danielcdh, jmolloy, sanjoy, dberlin, ruiu

Reviewed By: ruiu

Subscribers: ruiu, llvm-commits

Differential Revision: https://reviews.llvm.org/D45142

llvm-svn: 330059
2018-04-13 19:47:57 +00:00
David Blaikie 2be3922807 Fix a couple of layering violations in Transforms
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.

Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.

Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.

llvm-svn: 328165
2018-03-21 22:34:23 +00:00
Alexander Ivchenko 836eac3e8d Add missed PostDominatorTree analysis dependency to GVN hoist pass.
Summary:
GVN hoist pass is using PostDominatorTree analysis, therefore the analysis
should be listed in the pass initialization as a dependency.

Reviewed By: sebpop

Differential Revision: https://reviews.llvm.org/D43007

Author: ashlykov <arkady.shlykov@intel.com>
llvm-svn: 324597
2018-02-08 11:45:36 +00:00
Hiroshi Inoue c8e9245816 [NFC] fix trivial typos in comments and documents
"to to" -> "to"

llvm-svn: 323628
2018-01-29 05:17:03 +00:00
Aditya Kumar 1f90cae80f [GVNHoist] Fix: PR35222 gvn-hoist incorrectly erases load in case of a loop
Reviewers:
    dberlin
    sebpop
    eli.friedman

Differential Revision: https://reviews.llvm.org/D41453

llvm-svn: 321789
2018-01-04 07:47:24 +00:00
Aditya Kumar 49c03b11df [GVNHoist] Fix: PR35222 gvn-hoist incorrectly erases load
w.r.t. the paper
"A Practical Improvement to the Partial Redundancy Elimination in SSA Form"
(https://sites.google.com/site/jongsoopark/home/ssapre.pdf)

Proper dominance check was missing here, so having a loopinfo should not be required.
Committing this diff as this fixes the bug, if there are
further concerns, I'll be happy to work on them.

Differential Revision: https://reviews.llvm.org/D39781

llvm-svn: 320607
2017-12-13 19:40:07 +00:00
Craig Topper 062bcf30b1 [GVNHoist] Fix a signed/unsigned comparison warning that occurs in 32-bit builds with gcc.
std::distance returns ptrdiff_t which is signed. 64-bit builds don't notice because type promotion widens the unsigned first.

llvm-svn: 318354
2017-11-16 00:19:59 +00:00
Dan Gohman 2c74fe977d Add an @llvm.sideeffect intrinsic
This patch implements Chandler's idea [0] for supporting languages that
require support for infinite loops with side effects, such as Rust, providing
part of a solution to bug 965 [1].

Specifically, it adds an `llvm.sideeffect()` intrinsic, which has no actual
effect, but which appears to optimization passes to have obscure side effects,
such that they don't optimize away loops containing it. It also teaches
several optimization passes to ignore this intrinsic, so that it doesn't
significantly impact optimization in most cases.

As discussed on llvm-dev [2], this patch is the first of two major parts.
The second part, to change LLVM's semantics to have defined behavior
on infinite loops by default, with a function attribute for opting into
potential-undefined-behavior, will be implemented and posted for review in
a separate patch.

[0] http://lists.llvm.org/pipermail/llvm-dev/2015-July/088103.html
[1] https://bugs.llvm.org/show_bug.cgi?id=965
[2] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118632.html

Differential Revision: https://reviews.llvm.org/D38336

llvm-svn: 317729
2017-11-08 21:59:51 +00:00
Mandeep Singh Grang f83268bd9e [GVNHoist] Fix non-deterministic sort order of PHIs for identical instructions
Summary: This fixes failure in Transforms/GVNHoist/hoist.ll uncovered by D39245.

Reviewers: hiraditya, spop, dberlin

Reviewed By: dberlin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39410

llvm-svn: 316949
2017-10-30 19:42:41 +00:00
Eugene Zelenko 3b87939604 [Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 315760
2017-10-13 21:17:07 +00:00
Aditya Kumar dfa8741c96 [GVNHoist] Factor out reachability to search for anticipable instructions quickly
Factor out the reachability such that multiple queries to find reachability of values are fast. This is based on finding
the ANTIC points
in the CFG which do not change during hoisting. The ANTIC points are basically the dominance-frontiers in the inverse
graph. So we introduce a data structure (CHI nodes)
to keep track of values flowing out of a basic block. We only do this for values with multiple occurrences in the
function as they are the potential hoistable candidates.

This patch allows us to hoist instructions to a basic block with >2 successors, as well as deal with infinite loops in a
trivial way.
Relevant test cases are added to show the functionality as well as regression fixes from PR32821.

Regression from previous GVNHoist:
We do not hoist fully redundant expressions because fully redundant expressions are already handled by NewGVN

Differential Revision: https://reviews.llvm.org/D35918
Reviewers: dberlin, sebpop, gberry,

llvm-svn: 313116
2017-09-13 05:28:03 +00:00
Reid Kleckner 0e8c4bb055 Sink some IntrinsicInst.h and Intrinsics.h out of llvm/include
Many of these uses can get by with forward declarations. Hopefully this
speeds up compilation after adding a single intrinsic.

llvm-svn: 312759
2017-09-07 23:27:44 +00:00
Davide Italiano 32504cf661 [GVNHoist] Move duplicated code to a helper function. NFCI.
llvm-svn: 312575
2017-09-05 20:49:41 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Nikolai Bozhenov 9e4a1c39db [GVNHoist] Mark GlobalsAA as preserved by GVNHoist.
Reviewers: sebpop, hiraditya

Reviewed By: sebpop

Subscribers: n.bozhenov, llvm-commits

Differential Revision: https://reviews.llvm.org/D32158
Patch by Andrei Elovikov <andrei.elovikov@intel.com>

llvm-svn: 300552
2017-04-18 13:25:49 +00:00
Daniel Berlin 554dcd8c89 MemorySSA: Move to Analysis, from Transforms/Utils. It's used as
Analysis, it has Analysis passes, and once NewGVN is made an Analysis,
this removes the cross dependency from Analysis to Transform/Utils.
NFC.

llvm-svn: 299980
2017-04-11 20:06:36 +00:00
Geoff Berry 635e505675 [GVNHoist] Call isGuaranteedToTransferExecutionToSuccessor on each instruction
w.r.t. https://bugs.llvm.org/show_bug.cgi?id=32153
The consensus seems to be isGuaranteedToTransferExecutionToSuccessor should be called for each function.

Patch by Aditya Kumar

Differential Revision: https://reviews.llvm.org/D31035

llvm-svn: 299882
2017-04-10 20:45:17 +00:00
Daniel Berlin dcb004fdf1 Move defClobbersUseOrDef to being a protected member of a class since we don't want anyone else using it
llvm-svn: 296838
2017-03-02 23:06:46 +00:00
Hans Wennborg 19c0be90f9 [GVNHoist] Don't hoist unsafe scalars at -Oz (PR31729)
Based on Aditya Kumar's patch:

Differential Revision: https://reviews.llvm.org/D29092

llvm-svn: 296642
2017-03-01 17:15:08 +00:00
Daniel Berlin 17e8d0eae2 Move updating functions to MemorySSAUpdater.
Add updater to passes that now need it.
Move around code in MemorySSA to expose needed functions.

Summary: Mostly cleanup

Reviewers: george.burgess.iv

Subscribers: llvm-commits, Prazek

Differential Revision: https://reviews.llvm.org/D30221

llvm-svn: 295887
2017-02-22 22:19:55 +00:00
Reid Kleckner 79e37d517c Revert "[GVNHoist] Merge DebugLoc metadata on hoisted instructions"
This reverts commit r294250. It caused PR31891.

Add a test case that shows that inlinable calls retain location
information with an accurate scope.

llvm-svn: 294317
2017-02-07 17:31:13 +00:00
Taewook Oh 44a856f7d5 [GVNHoist] Merge DebugLoc metadata on hoisted instructions
Summary:
When instructions are hoisted, current implementation keeps DebugLoc metadata of the instruction that chosen as Repl (and its GEP operand if Repl is a load or a store). However, DebugLoc metadata should be updated to the 'merged' location across all hoisted instructions. See the following example code:


```
  1:  typedef struct {
  2:    int a[10];
  3:  } S1;
  4: 
  5:  extern S1 *s1[10];
  6: 
  7:  void foo(int x, int y, int i) {
  8:    if (y)
  9:      s1[i]->a[i] = x + y;
 10:    else
 11:      s1[i]->a[i] = x;
 12:  }
```

Below is LLVM IR representation of the program before gvn-hoist:


```
%struct.S1 = type { [10 x i32] }
@s1 = external local_unnamed_addr global [10 x %struct.S1*], align 16

define void @foo(i32 %x, i32 %y, i32 %i) !dbg !4 {
entry:
  %tobool = icmp ne i32 %y, 0, !dbg !8
  br i1 %tobool, label %if.then, label %if.else, !dbg !10

if.then:                                          ; preds = %entry
  %add = add nsw i32 %x, %y, !dbg !11
  %idxprom = sext i32 %i to i64, !dbg !12
  %arrayidx = getelementptr inbounds [10 x %struct.S1*], [10 x %struct.S1*]* @s1, i64 0, i64 %idxprom, !dbg !12
  %0 = load %struct.S1*, %struct.S1** %arrayidx, align 8, !dbg !12, !tbaa !13
  %a = getelementptr inbounds %struct.S1, %struct.S1* %0, i32 0, i32 0, !dbg !17
  br label %if.end, !dbg !12

if.else:                                          ; preds = %entry
  %idxprom3 = sext i32 %i to i64, !dbg !18
  %arrayidx4 = getelementptr inbounds [10 x %struct.S1*], [10 x %struct.S1*]* @s1, i64 0, i64 %idxprom3, !dbg !18
  %1 = load %struct.S1*, %struct.S1** %arrayidx4, align 8, !dbg !18, !tbaa !13
  %a5 = getelementptr inbounds %struct.S1, %struct.S1* %1, i32 0, i32 0, !dbg !19
  br label %if.end

if.end:                                           ; preds = %if.else, %if.then
  %a5.sink = phi [10 x i32]* [ %a5, %if.else ], [ %a, %if.then ]
  %.sink = phi i32 [ %x, %if.else ], [ %add, %if.then ]
  %idxprom6 = sext i32 %i to i64
  %arrayidx7 = getelementptr inbounds [10 x i32], [10 x i32]* %a5.sink, i64 0, i64 %idxprom6
  store i32 %.sink, i32* %arrayidx7, align 4, !tbaa !20
  ret void, !dbg !22
}

```
where


```
!11 = !DILocation(line: 9, column: 18, scope: !9)
!12 = !DILocation(line: 9, column: 5, scope: !9)
!18 = !DILocation(line: 11, column: 5, scope: !9)
!19 = !DILocation(line: 11, column: 9, scope: !9)
```

. And below is after gvn-hoist:


```
define void @foo(i32 %x, i32 %y, i32 %i) !dbg !4 {
entry:
  %tobool = icmp ne i32 %y, 0, !dbg !8
  %idxprom = sext i32 %i to i64, !dbg !10
  %0 = getelementptr inbounds [10 x %struct.S1*], [10 x %struct.S1*]* @s1, i64 0, i64 %idxprom, !dbg !10
  %1 = load %struct.S1*, %struct.S1** %0, align 8, !dbg !10, !tbaa !11
  br i1 %tobool, label %if.then, label %if.else, !dbg !15

if.then:                                          ; preds = %entry
  %add = add nsw i32 %x, %y, !dbg !16
  %arrayidx = getelementptr inbounds [10 x %struct.S1*], [10 x %struct.S1*]* @s1, i64 0, i64 %idxprom, !dbg !10
  %a = getelementptr inbounds %struct.S1, %struct.S1* %1, i32 0, i32 0, !dbg !17
  br label %if.end, !dbg !10

if.else:                                          ; preds = %entry
  %arrayidx4 = getelementptr inbounds [10 x %struct.S1*], [10 x %struct.S1*]* @s1, i64 0, i64 %idxprom, !dbg !18
  %a5 = getelementptr inbounds %struct.S1, %struct.S1* %1, i32 0, i32 0, !dbg !19
  br label %if.end

if.end:                                           ; preds = %if.else, %if.then
  %a5.sink = phi [10 x i32]* [ %a5, %if.else ], [ %a, %if.then ]
  %.sink = phi i32 [ %x, %if.else ], [ %add, %if.then ]
  %arrayidx7 = getelementptr inbounds [10 x i32], [10 x i32]* %a5.sink, i64 0, i64 %idxprom
  store i32 %.sink, i32* %arrayidx7, align 4, !tbaa !20
  ret void, !dbg !22
}

```
As you see, loads and their GEPs have been hosited from if.then/if.else block to entry block. However, DebugLoc metadata of these new instructions are still same as the instructions in if.then block, as they are moved/cloned from if.then block. This may result incorrect stepping and imprecise sample profile result.

Reviewers: majnemer, pcc, sebpop

Reviewed By: sebpop

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29377

llvm-svn: 294250
2017-02-06 22:05:04 +00:00
Eli Friedman c6885fc369 [GVNHoist] Invalidate MemDep when an instruction is moved.
See also r279907.

Fixes https://llvm.org/bugs/show_bug.cgi?id=30991 .

Differential Revision: https://reviews.llvm.org/D27493

llvm-svn: 288968
2016-12-07 19:55:59 +00:00
Aditya Kumar 314ebe05ac [GVNHoist] Rename variables.
Differential Revision: https://reviews.llvm.org/D27110

llvm-svn: 288142
2016-11-29 14:36:27 +00:00
Aditya Kumar 07cb304826 [GVNHoist] Enable aggressive hoisting when optimizing for code-size
Enable scalar hoisting at -Oz as it is safe to hoist scalars to a place
where they are partially needed.

Differential Revision: https://reviews.llvm.org/D27111

llvm-svn: 288141
2016-11-29 14:34:01 +00:00
George Burgess IV 66837aba0a [MemorySSA] Tighten up types to make our API prettier. NFC.
Patch by bryant.

Differential Revision: https://reviews.llvm.org/D26126

llvm-svn: 285750
2016-11-01 21:17:46 +00:00
Sebastian Pop 5ba9f24ed7 commit back "GVN-hoist: fix store past load dependence analysis (PR30216, PR30499)"
This is with an extra change to avoid calling MemoryLocation::get() on a call instruction.

Differential Revision: https://reviews.llvm.org/D25542

llvm-svn: 284098
2016-10-13 01:39:10 +00:00