Commit Graph

57 Commits

Author SHA1 Message Date
Jun Bum Lim 10e58e867d Fixed typo in r260530
llvm-svn: 260541
2016-02-11 16:46:13 +00:00
Jun Bum Lim 339e9723c1 [InstCombine] Simplify a known nonzero incoming value of PHI
Summary:
When a PHI is used only to be compared with zero, it is possible to replace an
incoming value with any non-zero constant if the incoming value can be proved as
a known nonzero value. For example, in below code, we can replace the incoming value %v with
any non-zero constant based on the fact that the PHI is only used to be compared with zero
and %v is a known non-zero value:
  %v = select %cond, 1, 2
  %p = phi [%v, BB] ...
  %c = icmp eq, %p, 0

Reviewers: mcrosier, jmolloy, sanjoy

Subscribers: hfinkel, mcrosier, majnemer, llvm-commits, haicheng, bmakam, mssimpso, gberry

Differential Revision: http://reviews.llvm.org/D16240

llvm-svn: 260530
2016-02-11 15:50:07 +00:00
Sanjay Patel 4b198802b3 function names start with a lowercase letter; NFC
llvm-svn: 259425
2016-02-01 22:23:39 +00:00
David Majnemer eafa28a0d9 [InstCombine] Teach FoldPHIArgZextsIntoPHI about EHPads
FoldPHIArgZextsIntoPHI cannot insert an instruction after the PHI if
there is an EHPad in the BB.  Doing so would result in an instruction
inserted after a terminator.

llvm-svn: 252377
2015-11-07 00:52:53 +00:00
David Majnemer 27f2447fb3 [InstCombine] Don't insert an instruction after a terminator
We tried to insert a cast of a phi in a block whose terminator is an
EHPad.  This is invalid.  Do not attempt the transform in these
circumstances.

llvm-svn: 252370
2015-11-06 23:59:23 +00:00
Artur Pilipenko 5c5011d503 Preserve load alignment and dereferenceable metadata during some transformations
Reviewed By: hfinkel

Differential Revision: http://reviews.llvm.org/D13953

llvm-svn: 251809
2015-11-02 17:53:51 +00:00
Duncan P. N. Exon Smith 9f8aaf21ba InstCombine: Remove ilist iterator implicit conversions, NFC
Stop relying on implicit conversions of ilist iterators in
LLVMInstCombine.  No functionality change intended.

llvm-svn: 250183
2015-10-13 16:59:33 +00:00
Sanjay Patel 9533407566 [InstCombine] fold zexts and constants into a phi (PR24766)
This is one step towards solving PR24766:
https://llvm.org/bugs/show_bug.cgi?id=24766

We were not producing the same IR for these two C functions because the store
to the temp bool causes extra zexts:

#include <stdbool.h>

bool switchy(char x1, char x2, char condition) {
   bool conditionMet = false;
   switch (condition) {
   case 0: conditionMet = (x1 == x2); break;
   case 1: conditionMet = (x1 <= x2); break;
   }
   return conditionMet;
}

bool switchy2(char x1, char x2, char condition) {
   switch (condition) {
   case 0: return (x1 == x2);
   case 1: return (x1 <= x2);
   }
  return false;
}

As noted in the code comments, this test case manages to avoid the more general existing
phi optimizations where there are only 2 phi inputs or where there are no constant phi 
args mixed in with the casts ops. It seems like a corner case, but if we don't catch it, 
then I don't think we can get SimplifyCFG to further optimize towards the canonical form
for this function shown in the bug report.

Differential Revision: http://reviews.llvm.org/D12866

llvm-svn: 248689
2015-09-27 20:34:31 +00:00
Akira Hatanaka f6afd11538 [InstCombine] Preserve metadata when merging loads that are phi
arguments.

Make sure InstCombiner::FoldPHIArgLoadIntoPHI doesn't drop the following
metadata:

MD_tbaa
MD_alias_scope
MD_noalias
MD_invariant_load
MD_nonnull
MD_range

rdar://problem/17617709

Differential Revision: http://reviews.llvm.org/D12710

llvm-svn: 248419
2015-09-23 18:40:57 +00:00
David Majnemer 8ed559ad22 Revert "[InstCombinePHI] Partial simplification of identity operations."
This reverts commit r244887, it caused PR24470.

llvm-svn: 245194
2015-08-17 03:11:26 +00:00
Charlie Turner 6153698f26 [InstCombinePHI] Partial simplification of identity operations.
Consider this code:

BB:
  %i = phi i32 [ 0, %if.then ], [ %c, %if.else ]
  %add = add nsw i32 %i, %b
  ...

In this common case the add can be moved to the %if.else basic block, because
adding zero is an identity operation. If we go though %if.then branch it's
always a win, because add is not executed; if not, the number of instructions
stays the same.

This pattern applies also to other instructions like sub, shl, shr, ashr | 0,
mul, sdiv, div | 1.

Patch by Jakub Kuderski!

llvm-svn: 244887
2015-08-13 12:38:58 +00:00
Sanjay Patel 9b7e6776a1 don't repeat function names in comments; NFC
llvm-svn: 240478
2015-06-23 23:05:08 +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
Pete Cooper 833f34d837 Convert PHI getIncomingValue() to foreach over incoming_values(). NFC.
We already had a method to iterate over all the incoming values of a PHI.  This just changes all eligible code to use it.

Ineligible code included anything which cared about the index, or was also trying to get the i'th incoming BB.

llvm-svn: 237169
2015-05-12 20:05:31 +00:00
David Blaikie 741c8f81e4 [opaque pointer type] Start migrating GEP creation to explicitly specify the pointee type
I'm just going to migrate these in a pretty ad-hoc & incremental way -
providing the backwards compatible API for now, then locally removing
it, fixing a few callers, adding it back in and commiting those callers.
Rinse, repeat.

The assertions should ensure that if I get this wrong we'll find out
about it and not just have one giant patch to revert, recommit, revert,
recommit, etc.

llvm-svn: 232240
2015-03-14 01:53:18 +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
Chandler Carruth a917458203 [PM] Rename InstCombine.h to InstCombineInternal.h in preparation for
creating a non-internal header file for the InstCombine pass.

I thought about calling this InstCombiner.h or in some way more clearly
associating it with the InstCombiner clas that it is primarily defining,
but there are several other utility interfaces defined within this for
InstCombine. If, in the course of refactoring, those end up moving
elsewhere or going away, it might make more sense to make this the
combiner's header alone.

Naturally, this is a bikeshed to a certain degree, so feel free to lobby
for a different shade of paint if this name just doesn't suit you.

llvm-svn: 226783
2015-01-22 05:25:13 +00:00
Chandler Carruth 66b3130cda [PM] Split the AssumptionTracker immutable pass into two separate APIs:
a cache of assumptions for a single function, and an immutable pass that
manages those caches.

The motivation for this change is two fold. Immutable analyses are
really hacks around the current pass manager design and don't exist in
the new design. This is usually OK, but it requires that the core logic
of an immutable pass be reasonably partitioned off from the pass logic.
This change does precisely that. As a consequence it also paves the way
for the *many* utility functions that deal in the assumptions to live in
both pass manager worlds by creating an separate non-pass object with
its own independent API that they all rely on. Now, the only bits of the
system that deal with the actual pass mechanics are those that actually
need to deal with the pass mechanics.

Once this separation is made, several simplifications become pretty
obvious in the assumption cache itself. Rather than using a set and
callback value handles, it can just be a vector of weak value handles.
The callers can easily skip the handles that are null, and eventually we
can wrap all of this up behind a filter iterator.

For now, this adds boiler plate to the various passes, but this kind of
boiler plate will end up making it possible to port these passes to the
new pass manager, and so it will end up factored away pretty reasonably.

llvm-svn: 225131
2015-01-04 12:03:27 +00:00
David Blaikie 70573dcd9f Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

llvm-svn: 222334
2014-11-19 07:49:26 +00:00
Hal Finkel 60db05896a Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.)
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.

As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.

The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.

Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.

This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).

llvm-svn: 217342
2014-09-07 18:57:58 +00:00
Craig Topper 71b7b68b74 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 216158
2014-08-21 05:55:13 +00:00
Craig Topper 6230691c91 Revert "Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size."
Getting a weird buildbot failure that I need to investigate.

llvm-svn: 215870
2014-08-18 00:24:38 +00:00
Craig Topper 5229cfd163 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.
llvm-svn: 215868
2014-08-17 23:47:00 +00:00
Craig Topper f40110f4d8 [C++] Use 'nullptr'. Transforms edition.
llvm-svn: 207196
2014-04-25 05:29:35 +00:00
Chandler Carruth 964daaaf19 [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

llvm-svn: 206844
2014-04-22 02:55:47 +00:00
Chandler Carruth 5f1f26e891 [Modules] Sink all the DEBUG_TYPE defines for InstCombine out of the
header files and into the cpp files.

These files will require more touches as the header files actually use
DEBUG(). Eventually, I'll have to introduce a matched #define and #undef
of DEBUG_TYPE for the header files, but that comes as step N of many to
clean all of this up.

llvm-svn: 206777
2014-04-21 19:51:41 +00:00
Chandler Carruth cdf4788401 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

llvm-svn: 203364
2014-03-09 03:16:01 +00:00
Rafael Espindola 37dc9e19f5 Rename many DataLayout variables from TD to DL.
I am really sorry for the noise, but the current state where some parts of the
code use TD (from the old name: TargetData) and other parts use DL makes it
hard to write a patch that changes where those variables come from and how
they are passed along.

llvm-svn: 201827
2014-02-21 00:06:31 +00:00
Benjamin Kramer 30d249a1b3 Push analysis passes to InstSimplify when they're around anyways.
llvm-svn: 191309
2013-09-24 16:37:40 +00:00
Eli Friedman 77d7fbb924 Get rid of unused isPodLike definitions.
llvm-svn: 190461
2013-09-11 00:36:54 +00:00
Matt Arsenault e6db76071c Consistently use dbgs() in debug printing
llvm-svn: 190093
2013-09-05 19:48:28 +00:00
Jim Grosbach bdbd73460c Tidy up a bit. No functional change.
llvm-svn: 178915
2013-04-05 21:20:12 +00:00
Chandler Carruth 9fb823bbd4 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366
2013-01-02 11:36:10 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Micah Villmow cdfe20b97f Move TargetData to DataLayout.
llvm-svn: 165402
2012-10-08 16:38:25 +00:00
Eli Friedman 8bc586e770 Update instcombine for atomic load/store.
llvm-svn: 137664
2011-08-15 22:09:40 +00:00
Frits van Bommel ede0dc6dda Shorten some expressions by using ArrayRef::slice().
llvm-svn: 135910
2011-07-25 15:13:01 +00:00
Jay Foad d1b7849d49 Convert GetElementPtrInst to use ArrayRef.
llvm-svn: 135904
2011-07-25 09:48:08 +00:00
Chris Lattner 229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Eli Friedman 35211c6091 Final step of instcombine debuginfo; switch a couple more places over to InsertNewInstWith, and use setDebugLoc for the cases which can't be easily handled by the automated mechanisms.
llvm-svn: 132167
2011-05-27 00:19:40 +00:00
Duncan Sands 085ad3b81a Stop trying to have instcombine preserve LCSSA form: this was not
effective in avoiding recomputation of LCSSA form; the widespread
use of instsimplify (which looks through phi nodes) means it was
not preserving LCSSA form anyway; and instcombine is no longer
scheduled in the middle of the loop passes so this doesn't matter
anymore.

llvm-svn: 130301
2011-04-27 10:55:12 +00:00
Frits van Bommel d6d4f987b4 Rename a misleadingly-named variable.
llvm-svn: 129644
2011-04-16 14:32:34 +00:00
Jay Foad 7d03e9be47 Fix bug when checking phi operands in InstCombiner::visitPHINode(),
found by code inspection.

llvm-svn: 129641
2011-04-16 14:17:37 +00:00
Chris Lattner 0ab5e2cded Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
2011-04-15 05:18:47 +00:00
Jay Foad 52131344a2 Remove PHINode::reserveOperandSpace(). Instead, add a parameter to
PHINode::Create() giving the (known or expected) number of operands.

llvm-svn: 128537
2011-03-30 11:28:46 +00:00
Jay Foad e0938d8a87 (Almost) always call reserveOperandSpace() on newly created PHINodes.
llvm-svn: 128535
2011-03-30 11:19:20 +00:00
Jay Foad 1c83965f5a Make more use of PHINode::getNumIncomingValues().
llvm-svn: 128406
2011-03-28 13:03:10 +00:00
Chris Lattner a8fed47eed have instcombine preserve nsw/nuw/exact when sinking
common operations through a phi. 

llvm-svn: 125790
2011-02-17 23:01:49 +00:00
Chris Lattner 75ae5a45ff fix typo
llvm-svn: 125787
2011-02-17 22:32:54 +00:00