The number of SCEV expressions is usually linear in the number of IR
instructions being modeled. However, a naive SCEV visitor is not. For
an expression like x*x, "x" will be visited twice. If x is itself an
expression like x*x, that will be visited twice, etc, and the overall
runtime is O(2^N) in the number of SCEV expressions.
To prevent this from happening, add a cache, so we only visit each SCEV
expression once.
Not sure this is the best solution. Maybe we can instead check whether
the SCEV is scop-invariant (in which case we never need to map the
value). But we don't have a utility for that at the moment.
Differential Revision: https://reviews.llvm.org/D47087
llvm-svn: 335783
Move the optimized getDefToTarget() from ForwardOpTree to ZoneAlgo such
that it can be used by makeValInst.
This reduces the compile time of GrTestUtils of the aosp buildbot from
2m46s to 21s, which should fix the timeout issue.
Differential Revision: https://reviews.llvm.org/D48579
llvm-svn: 335606
Summary:
The function is currently awfully complicated. Drop the IILE and use
StringRef over std::string.
Reviewers: Meinersbur, grosser, bollu
Reviewed By: Meinersbur
Subscribers: nemanjai, kbarton, bollu, llvm-commits, pollydev
Differential Revision: https://reviews.llvm.org/D48070
llvm-svn: 334695
First build the surrounding loops and then build up the polyhedral
structures. Before r326664 we had to mix these updates, clean this
up to improve readability (slightly).
llvm-svn: 334412
In case the schedule has not changed and the operand tree root uses a
value defined in an ancestor loop, the def-to-target mapping is trivial.
For instance, the SCoP
for (int i < 0; i < N; i+=1) {
DefStmt:
D = ...;
for (int j < 0; j < N; j+=1) {
TargetStmt:
use(D);
}
}
has DefStmt-to-TargetStmt mapping of
{ DefStmt[i] -> TargetStmt[i,j] }
This should apply on the majority of def-to-target mappings.
This patch detects this case and directly constructs the expected
mapping. It assumes that the mapping never crosses the loop header
DefStmt is in, which ForwardOpTree does not support at the moment
anyway.
Differential Revision: https://reviews.llvm.org/D47752
llvm-svn: 334134
The aosp-O3-polly-before-vectorizer-unprofitable buildbot currently
fails in ZoneAlgorithm::isNormalized, presumably because an
out-of-quota happens in that function.
Modify ZoneAlgorithm::isNormalized to return an isl::boolean such
it can report an error.
In the failing case, it was called in an assertion in ForwardOpTree.
Allow to pass the assertion in an out-of-quota event, a condition that
is later checked before forwarding an operand tree.
llvm-svn: 333709
This update adds new list types and adds functions which convert isl
data types to lists of their contained elements:
isl::set::get_basic_set_list
isl::union_set::get_set_list
isl::map::get_basic_map_list
isl::union_map::get_map_list
llvm-svn: 333688
Besides other changes, this update introduces functions to translate a
maps and sets into lists of their elements. These lists are useful as
we can define iterators for lists, which allow us to replace many uses
of foreach.
llvm-svn: 333621
When forwarding a LoadInst to another statement, a map that translates
their domain is needed. Before this patch, is was computed by appending
the def-to-use map to the def-to-target of the operand tree's target.
This patch lets the new method getDefToTarget do this. This is
computationally less expensive due to:
* Caching of the result such that it can be used for multiple operands
tree to the same target.
* The map is only computed when there is a LoadInst that needs it.
* It is only computed for the statement requiring the translator map,
instead of having an intermediate result for every edge in the
operand tree.
The downside is that this scheme cannot handle forwarding from a
previous loop iteration (which would require the entire path from
statement to target). Since ForwardOpTree currently does not support
forwarding across loop iterations (SCEV expressions would need to be
transformed), this was not needed anyway.
Differential Revision: https://reviews.llvm.org/D47385
llvm-svn: 333426
Summary: This patch updates `Scop::addUserContext()` function to the new C++ interface and replaces the `auto` keyword with explicit type wherever used in this function.
Reviewers: grosser, bollu, philip.pfaffe, chelini, Meinersbur
Reviewed By: grosser
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47438
llvm-svn: 333366
Besides normal updates this change also contains a bug-fix to in
isl_coalesce which broke the AOSP buildbot. Thanks to Michael Kruse for
reporting this bug and Sven Verdoolage for fixing this bug.
llvm-svn: 333118
An assertion was not prepared to be passed a nullptr because the
out-of-quota limit was exceeded. Bail-out before the assertion
since the assertion does not apply on out-of-quote.
This fixes llvm.org/PR37477.
llvm-svn: 332488
Summary: This patch aims to remove the usage of old C-styled isl functions (in this case `isl_set_n_basic_set()`) in favor of new C++ isl interface based methods in `ScopInfo.cpp`.
Patch by Sahil Yerawar
Differential Revision: https://reviews.llvm.org/D46935
llvm-svn: 332471
Summary: Creating the Scop name is expensive, because creating the
Region name it's derived from is expensive. So create the name lazily,
because getName() is actually called rarely.
This is a reiteration of r328666, which introduced a use-after-free and
got reverted in r331363.
Differential Revision: https://reviews.llvm.org/D46868
llvm-svn: 332359
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
Differential Revision: https://reviews.llvm.org/D44978
llvm-svn: 332352
nullptr is not a valid affine expression, and none of the callers check
for null, so we eventually hit an isl error and crash.
Instead, invalidate the scop and return a constant zero.
Differential Revision: https://reviews.llvm.org/D46445
llvm-svn: 332309
The condition was introduced in r267142 to mitigate a long compile-time
case. In r306087, a max-computation limit was introduced that should
handle the same case while leaving the max disjuncts heuristic it
should have replaced intact.
Today, the max disjuncts bail-out causes problems in that it prematurely
stops SCoPs from being detected, e.g. in SPEC's lbm. This would hit less
like if isl_set_coalesce would be called after isl_set_remove_divs
(which makes more basic_set likely to be coalescable) instead of before.
This patch tries to remove the premature max-disjuncts bail-out
condition by using simple_hull() to reduce the computational overhead,
instead of directly invalidating that SCoP.
Differential Revision: https://reviews.llvm.org/D45066
Contributed-by: Sahil Girish Yerawar <cs15btech11044@iith.ac.in>
llvm-svn: 331891
This reverts commit 0f9dc03765dc301fff7a52e2a0e1dd3e5f3130c5, r328666.
The change introduced a use-after-free, caused by the temporary name string
being destroyed after converting it to a StringRef.
llvm-svn: 331363
These functions have been legacy leftovers which we used before the
official C++ bindings existed. As all uses of these legacy functions
have been removed, this polly-specific extension can also be dropped.
llvm-svn: 331130
Add the options -polly-codegen-trace-stmts and
-polly-codegen-trace-scalars. When enabled, adds a call to the
beginning of every generated statement that prints the executed
statement instance. With -polly-codegen-trace-scalars, it also prints
the value of all scalars that are used in the statement, and PHIs
defined in the beginning of the statement.
Differential Revision: https://reviews.llvm.org/D45743
llvm-svn: 330864
The current statement domain derivation algorithm does not (always)
consider that different exit blocks of a loop can have different
conditions to be reached.
From the code
for (int i = n; ; i-=2) {
if (i <= 0) goto even;
if (i <= 1) goto odd;
A[i] = i;
}
even:
A[0] = 42;
return;
odd:
A[1] = 21;
return;
Polly currently derives the following domains:
Stmt_even_critedge
Domain :=
[n] -> { Stmt_even_critedge[] };
Stmt_odd
Domain :=
[n] -> { Stmt_odd[] : (1 + n) mod 2 = 0 and n > 0 };
while the domain for the odd case is correct, Stmt_even is assumed to be
executed unconditionally, which is obviously wrong. While projecting out
the loop dimension in `adjustDomainDimensions`, it does not consider
that there are other exit condition that have matched before.
I don't know a how to fix this without changing a lot of code. Therefore
This patch rejects loops with multiple exist blocks to fix the
miscompile of test-suite's uuencode.
The odd condition is transformed by LLVM to
%cmp1 = icmp eq i64 %indvars.iv, 1
such that the project_out in adjustDomainDimensions() indeed only
matches for odd n (using this condition only, we'd have an infinite loop
otherwise).
The even condition manifests as
%cmp = icmp slt i64 %indvars.iv, 3
Because buildDomainsWithBranchConstraints() does not consider other exit
conditions, it has to assume that the induction variable will eventually
be lower than 3 and taking this exit.
IMHO we need to reuse the algorithm that determines the number of
iterations (addLoopBoundsToHeaderDomain) to determine which exit
condition applies first. It has to happen in
buildDomainsWithBranchConstraints() because the result will need to
propagate to successor BBs. Currently addLoopBoundsToHeaderDomain() just
look for union of all backedge conditions (which means leaving not the
loop here). The patch in llvm.org/PR35465 changes it to look for exit
conditions instead. This is required because there might be other exit
conditions that do not alternatively go back to the loop header.
Differential Revision: https://reviews.llvm.org/D45649
llvm-svn: 330858
Before this patch, ISL_ASSERT only printed an error message to stderr.
This can be easily missed if the program continues or just fails later.
To fail-early and help error diagnostics (e.g. using bugpoint), call
abort() when an assertion does not hold.
I seem to just have forgotten to add this abort() when I originally
proposed the ISL_ASSERT macro.
Suggested-By: Eli Friedman <efriedma@codeaurora.org>
Differential Revision: https://reviews.llvm.org/D45171
llvm-svn: 330467
Add the switch -polly-debug-func to define the name of a debug
function. This function is ignored for any validity check.
Its purpose is to allow to observe a value after transformation by a
SCoP, and to follow which statements are executed in which order. For
instance, consider the following code:
static void dbg_printf(int sum, int i) {
fprintf(stderr, "The value of sum is %d, i=%d\n", sum, i);
fflush(stderr);
}
void func(int n) {
int sum = 0;
for (int i = 0; i < 16; i+=1) {
sum += i;
dbg_printf(sum, i);
}
}
Executing this after Polly's codegen with -polly-debug-func=dbg_printf
reveals the new execution order and the assumed values at that point of
execution.
Differential Revision: https://reviews.llvm.org/D45728
llvm-svn: 330466
In r330292 this assert was turned incorrectly into an unreachable, but
the correct behavior (thanks Michael) is to assert for anything that is
not 64 bit, but falltrough for 64 bit. I document this in the source
code.
llvm-svn: 330309
Summary:
As of rL329273, LLVM has a mechanism to load new-pm plugins in opt. Use
this API in Polly.
Reviewers: grosser, Meinersbur, bollu
Reviewed By: grosser, Meinersbur
Subscribers: lksbhm, bollu, pollydev, llvm-commits
Differential Revision: https://reviews.llvm.org/D45484
llvm-svn: 330181
A check in assert-builds was meant to verify that a load provides a
value in all statement instances (i.e. its domain). The domain is
commonly gist'ed within the parameter context to contain fewer
constraints. However, statement instances outside the context are
no valid executions, hence the value provided can be undefined.
Refine the check for valid loads to only needed to be defined within
the SCoP context.
In addition, the JSONImporter had to be changed to allow importing
access relations that are broader than the current access relation,
but still defined over all statement instances.
This should fix the compiler crash in test-suite's oggenc of the
-polly-process-unprofitable buildbot.
llvm-svn: 329655
Commit r329640 introduced the removal of all MemoryAccesses of a Scop.
It accidentally continued iterating over a vector whose iterators
have been invalidated by a MemoryAccess removal.
Make a copy of the MemoryAccesses to remove to iterate over while
removing them.
llvm-svn: 329653
Removing a statement left its MemoryAccesses in some lists and maps of
the SCoP. Which lists depends on at which phase of the SCoP
construction the statement is deleted. Follow-up passes could still see
the already deleted MemoryAccesses by iterating through these
lists/maps, resulting in an access violation.
When removing a ScopStmt, also remove all its MemoryAccesses by using
the same mechnism that removes a MemoryAccess.
llvm-svn: 329640
std::remove, despite its name, does not remove elements from a list, but
only moves them to the end of a list. Call erase() to shorten the
vector to the remaining elements.
Test case included in next commit.
llvm-svn: 329639
This patch removes the heuristic in
- Polly :: lib/Support/ScopHelper.cpp
The heuristic forces blocks that directly follow a loop header to not to be considered error blocks.
It was introduced in r249611 with the following commit message:
> This replaces the support for user defined error functions by a
> heuristic that tries to determine if a call to a non-pure function
> should be considered "an error". If so the block is assumed not to be
> executed at runtime. While treating all non-pure function calls as
> errors will allow a lot more regions to be analyzed, it will also
> cause us to dismiss a lot again due to an infeasible runtime context.
> This patch tries to limit that effect. A non-pure function call is
> considered an error if it is executed only in conditionally with
> regards to a cheap but simple heuristic.
In the code below `CCK_Abort2()` would be considered as an error block, but not `CCK_Abort1()` due to this heuristic.
```
for (int i = 0; i < n; i+=1) {
if (ErrorCondition1)
CCK_Abort1(); // No __attribute__((noreturn))
if (ErrorCondition2)
CCK_Abort2(); // No __attribute__((noreturn))
}
```
This does not seem useful. Checking error conditions in the beginning of some work is quite common. It causes a switch default-case to be not considered an error block in SPEC's cactuBSSN. The comment justifying the heuristic mentions a "load", which does not seem to be applicable here. It has been proposed to remove the heuristic.
In addition, the patch fixes the following test cases:
- Polly :: ScopDetect/mod_ref_read_pointer.ll
- Polly :: ScopInfo/max-loop-depth.ll
- Polly :: ScopInfo/mod_ref_access_pointee_arguments.ll
- Polly :: ScopInfo/mod_ref_read_pointee_arguments.ll
- Polly :: ScopInfo/mod_ref_read_pointer.ll
- Polly :: ScopInfo/mod_ref_read_pointers.ll
The test cases failed after removing the heuristic.
Differential Revision: https://reviews.llvm.org/D45274
Contributed-by: Lorenzo Chelini <l.chelini@icloud.com>
llvm-svn: 329548
The warning is:
isl_union_map.c(2041): warning C4221: nonstandard extension used: 'filter_user': cannot be initialized using address of automatic variable 'data'
for the following code (and others)
struct isl_un_op_drop_user_data data = { &isl_set_is_wrapping };
struct isl_un_op_control control = {
.filter = &un_op_filter_drop_user,
.filter_user = &data,
.fn_map = &isl_set_wrapped_domain_map,
};
llvm-svn: 329328
Summary:
When checking the parallelism of a scheduling dimension, we first check if excluding reduction dependences the loop is parallel or not.
If the loop is not parallel, then we need to return the minimal dependence distance of all data dependences, including the previously subtracted reduction dependences.
Reviewers: grosser, Meinersbur, efriedma, eli.friedman, jdoerfert, bollu
Reviewed By: Meinersbur
Subscribers: llvm-commits, pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D45236
llvm-svn: 329214
This gets very expensive for basic blocks which don't have a name: it
calls printAsOperand, which numbers the entire module. We don't
normally need the name anyway, though; it's only used for debug dumps,
so don't compute it by default.
Differential Revision: https://reviews.llvm.org/D44946
llvm-svn: 328666
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.
Reviewers: grosser, efriedma, jdoerfert, bollu, sebpop
Reviewed By: sebpop
Subscribers: sebpop, mehdi_amini, llvm-commits, pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D44361
llvm-svn: 327361
Piecewise affine expressions have directly corresponding mathematical
operators. Introduce these operators as overloads as this makes writing
code with isl::pw_aff expressions more directly readable.
We can now write:
A = B + C instead of A = B.add(C)
llvm-svn: 327216
isl does not guarantee that set dimension ids will be preserved, so using them
to carry information is not a good idea. Furthermore, the loop information can
be derived without problem from the statement itself. As this even requires
less code than propagating loop information on set dimension ids, starting from
this commit we just derive the loop information in collectSurroundingLoops
directly from the IR.
Interestingly this also results in a couple of isl sets to take a simpler
representation.
llvm-svn: 326664
During codegen, Polly attempts to clear all loops from ScalarEvolution
and LoopInfo, and it does so one block at a time. This causes undefined
behaviour, since this way a loop header might be removed from a loop
before the entire loop is erased, causing ScalarEvolution to run into an
error.
Instead, just delete the entire loop atomically. This fixes currently
failing testcases.
llvm-svn: 326643
Also un-revert (isl_pw_*_alloc: add missing check for compatible spaces, Wed Sep
6 12:18:04 2017 +0200).
This patch is a proposed fix to avoid asserts due to stricter space checking
within isl, which resulted in failures when converting a schedule tree to
a schedule map.
llvm-svn: 326073
As part of this cleanup a couple of unnecessary isl::manage(obj.copy()) pattern
are eliminated as well.
We checked for all potential cleanups by scanning for:
"grep -R isl::manage\( lib/ | grep copy"
llvm-svn: 325558
This update:
- Removes several deprecated functions (e.g., isl_band).
- Improves the pretty-printing of sets by detecting modulos and "false"
equalities.
- Minor improvements to coalescing and increased robustness of the isl
scheduler.
This update does not yet include isl commit isl-0.18-90-gd00cb45
(isl_pw_*_alloc: add missing check for compatible spaces, Wed Sep 6 12:18:04
2017 +0200), as this additional check is too tight and unfortunately causes
two test case failures in Polly. A patch has been submitted to isl and will be
included in the next isl update for Polly.
llvm-svn: 325557
Two or more PHIs mutually using each other directly or indirectly as
incoming value could cause that a PHI WRITE be added before the PHI READ
(i.e. it overwrites the current incoming value with the next incoming
value before it being read).
Fix by ensuring that the PHI WRITE and PHI READ are in the same statement.
This should fix the miscompile of SingleSource/Benchmark/Misc/whetstone
from the test-suite.
llvm-svn: 324934
Splitting basic blocks into multiple statements if there are now
additional scalar dependencies gives more freedom to the scheduler, but
more statements also means higher compile-time complexity. Switch to
finer statement granularity, the additional compile time should be
limited by the number of operations quota.
The regression tests are written for the -polly-stmt-granularity=bb
setting, therefore we add that flag to those tests that break with the
new default. Some of the tests only fail because the statements are
named differently due to a basic block resulting in multiple statements,
but which are removed during simplification of statements without
side-effects. Previous commits tried to reduce this effect, but it is
not completely avoidable.
Differential Revision: https://reviews.llvm.org/D42151
llvm-svn: 324169
Do not add a "_last" suffix to the statement name if there is no (other)
main statement for a basic block. In other words, it becomes the main
statement itself. This further reduces the statement naming difference
between -polly-stmt-granularity=bb and
-polly-stmt-granularity=scalar-indep.
llvm-svn: 324168
Theoretically, a PHI write can be added to any statement that represents
the incoming basic block. We previously always chose the last because
the incoming value's definition is guaranteed to be defined.
With this patch the PHI write is added to the statement that defines the
incoming value. It avoids the requirement for a scalar dependency between
the defining statement and the statement containing the write. As such the
logic for -polly-stmt-granularity=scalar-indep that ensures that there is
such scalar dependencies can be removed.
Differential Revision: https://reviews.llvm.org/D42147
llvm-svn: 323284
VirtualUse::create is only called for MemoryKind::Value, but its
consistency nonetheless checked in verifyUses(). PHI uses are always
inter-stmt dependencies, which was not considered by the constructor
method. The virtual and non-virtual execution paths were the same, such
that verifyUses did not encounter any inconsistencies.
llvm-svn: 323283
The goal is to have -polly-stmt-granularity=bb and
-polly-stmt-granularity=scalar-indep to have the same names if there is
just one statement per basic block.
This fixes a fluke when Polybench's jacobi-2d is optimized differently
depending on the -polly-stmt-granularity option, although both options
create the same SCoP, just with different statement names.
The new naming scheme is:
With -polly-use-llvm-names=0:
Stmt<BBIdx as decimal><Idx within BB as letter>
With -polly-use-llvm-names=1:
Stmt_BBName_<Idx within BB as letter>
The <Idx within BB> suffix is omitted for the main statement of a BB. The
main statement is either the one containing the first store or call
(those cannot be removed by the simplifyer), or if there is no such
instruction, the first. If after simplification there is just a single
statement left, it should be the main statement and have the same names as
with -polly-stmt-granularity=bb.
Differential Revision: https://reviews.llvm.org/D42136
llvm-svn: 322852
This will give control of the statement's name to the caller.
Required to give -polly-stmt-granularity=scalar-indep more control
over the name of the generated statement in a follow-up commit.
llvm-svn: 322851
isl_val_get_num_si crashes on overflow, so don't use it on arbitrary
integers.
Testcase only crashes on platforms where long is 32 bits because of the
signature of isl_val_get_num_si; not sure if it's possible to write a
testcase which crashes if long is 64 bits.
There are a few other places in polly which use isl_val_get_num_si;
they probably need to be fixed as well. I don't think polly uses any
of the other "long" isl APIs in an unsafe manner.
Differential Revision: https://reviews.llvm.org/D42129
llvm-svn: 322766
Print same or similar structure elements together. Previously, the
value could take more importance that the space structure if visited
first in the space nest tree.
Before:
{
Left[0] -> Right[i]: i >= 0;
Left[1] -> AnotherRight[i];
Left[2] -> Right[-1]
}
After:
{
Left[0] -> Right[i]: i >= 0;
Left[2] -> Right[-1];
Left[1] -> AnotherRight[i]
}
llvm-svn: 322581
CMake insists that for each target, one uses only the non-keyword
version of target_link_library
target_link_library(mytarget lib)
or the one with PUBLIC/PRIVATE/INTERFACE keyword:
target_link_library(mytarget PUBLIC lib)
Otherwise, CMake fails with the error message:
The keyword signature for target_link_libraries has already been used with
the target "mytarget". All uses of target_link_libraries with a target
must be either all-keyword or all-plain.
Change all occurances of target_link_library to the newer keyworded
version to avoid such errors. Some already have been changed in r319840,
but might not be sufficient for all build configurations to build
the doxygen manual.
Reported-by: Tanya Lattner <tanyalattner@llvm.org>
llvm-svn: 322376
Memory transfer instructions take two pointers. It is not defined to
which of those a noalias annotation applies. To ensure correctness,
do not add noalias annotations to memcpy/memmove instructions anymore.
The caused a miscompile with test-suite's MultiSource/Applications/obsequi.
Since r321138, the MemCpyOpt pass would remove memcpy/memmove calls if
known to copy uninitialized memory. In that case, it was initialized
by another memcpy, but the annotation for the target pointer said
it would not alias. The annotation was actually meant for the source
pointer, which was was an alloca and could not alias with the target
pointer.
llvm-svn: 321371
Summary:
This can be seen as a follow-up on my previous differential [D33411](https://reviews.llvm.org/D33411).
We received a bug report where this error was triggered. I have tried my best to recreate the issue in a minimal lit testcase which is also part of this differential.
I only handle return instructions as predecessors to a virtual TLR-exit right now. From inspecting the codebase, it seems `unreachable` instructions may also be of interest here. If requested, I can extend my patches to consider them as well. I would also apply this on `ScopHelper.cpp::isErrorBlock` (see D33411), of course.
Reviewers: philip.pfaffe, bollu
Reviewed By: bollu
Subscribers: Meinersbur, pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D40492
llvm-svn: 319431
Eli Friedman