Enabling -keep-going in ScopDetection causes expansion to an invalid
Scop candidate.
Region A <- Valid candidate
|
Region B <- Invalid candidate
If -keep-going is enabled, ScopDetection would expand A to A+B because
the RejectLog is never checked for errors during expansion.
With this patch only A becomes a valid Scop.
llvm-svn: 211875
Use a container class to store the reject logs. Delegating most calls to
the internal std::map and add a few convenient shortcuts (e.g.,
hasErrors()).
llvm-svn: 211780
Add support for generating optimization remarks after completing the
detection of Scops.
The goal is to provide end-users with useful hints about opportunities that
help to increase the size of the detected Scops in their code.
By default the remark is unspecified and the debug location is empty. Future
patches have to expand on the messages generated.
This patch brings a simple test case for ReportFuncCall to demonstrate the
feature.
Reports all missed opportunities to increase the size/number of valid
Scops:
clang <...> -Rpass-missed="polly-detect" <...>
opt <...> -pass-remarks-missed="polly-detect" <...>
Reports beginning and end of all valid Scops:
clang <...> -Rpass="polly-detect" <...>
opt <...> -pass-remarks="polly-detect" <...>
Differential Revision: http://reviews.llvm.org/D4171
llvm-svn: 211769
Fixes#19976.
The error log does not contain an error, in case we reject a candidate
without generating a diagnostic message by using invalid<>(...). This is
the case for the top-level region of a function.
The patch comes without a test-case because adding a useful one requires
additional code just for triggering it. Before the patch it would only trigger,
if we try to print the CFG with Scop error annotations.
llvm-svn: 210753
Without this patch, the testcase would fail on the delinearization of the second
array:
; void foo(long n, long m, long o, double A[n][m][o]) {
; for (long i = 0; i < n; i++)
; for (long j = 0; j < m; j++)
; for (long k = 0; k < o; k++) {
; A[i+3][j-4][k+7] = 1.0;
; A[i][0][k] = 2.0;
; }
; }
; CHECK: [n, m, o] -> { Stmt_for_body6[i0, i1, i2] -> MemRef_A[3 + i0, -4 + i1, 7 + i2] };
; CHECK: [n, m, o] -> { Stmt_for_body6[i0, i1, i2] -> MemRef_A[i0, 0, i2] };
Here is the output of FileCheck on the testcase without this patch:
; CHECK: [n, m, o] -> { Stmt_for_body6[i0, i1, i2] -> MemRef_A[i0, 0, i2] };
^
<stdin>:26:2: note: possible intended match here
[n, m, o] -> { Stmt_for_body6[i0, i1, i2] -> MemRef_A[o0] };
^
It is possible to find a good delinearization for A[i][0][k] only in the context
of the delinearization of both array accesses.
There are two ways to delinearize together all array subscripts touching the
same base address: either duplicate the code from scop detection to first gather
all array references and then run the delinearization; or as implemented in this
patch, use the same delinearization info that we computed during scop detection.
llvm-svn: 210117
Instead of relying on the delinearization to infer the size of an element,
compute the element size from the base address type. This is a much more precise
way of computing the element size than before, as we would have mixed together
the size of an element with the strides of the innermost dimension.
llvm-svn: 209695
Support a 'keep-going' mode for the ScopDetection. In this mode, we just keep
on detecting, even if we encounter an error.
This is useful for diagnosing SCoP candidates. Sometimes you want all the
errors. Invalid SCoPs will still be refused in the end, we just refuse to
abort on the first error.
llvm-svn: 209574
This stores all RejectReasons created for one region
in a RejectLog inside the DetectionContext. For now
this only keeps track of the last error.
A separate patch will enable the tracking of all errors.
This patch itself does no harm (yet).
llvm-svn: 209572
definition below all of the header #include lines, Polly edition.
If you want to know more details about this, you can see the recent
commits to Debug.h in LLVM. This is just the Polly segment of a cleanup
I'm doing globally for this macro.
llvm-svn: 206852
This replaces the ancient INVALID/INVALID_NOVERIFY macros with a real
function.
The new invalid(..) function uses small diagnostic objects that are
generated on demand. We can store arbitrary additional information per
error type and generate useful debug/error messages on the fly.
Use it as follows:
if (/* Some error condition (ReportFoo) */)
invalid<ReportFoo>(Context, /*Assert=*/true/false,
(/* List of helpful diagnostic objects */));
Where ReportFoo is a subclass of RejectReason that is able to take the
list of helpful diagnostic objects in its constructor.
The implementation of invalid will create the report and fire
an assertion, if necessary.
llvm-svn: 205414
We mostly iterate over read-only values. Following a suggestion by Duncan P.N
Exons Smith, we use the construct 'const auto &' for this.
llvm-svn: 202651
clang-format requires a space before the ":" in the foreach loop. Even though
this is surprising to me, we follow this style to make our formatting
consistent with clang-format. I found that this clang-format style is used in a
couple of C++11 examples, hence I believe the fact that clang-format adds a
colon is not a bug but just something I was not used to yet.
llvm-svn: 202648
In rare cases the modification of one scop can effect the validity of other
scops, as code generation of an earlier scop may make the scalar evolution
functions derived for later scops less precise. The example that triggered this
patch was a scop that contained an 'or' expression as follows:
%add13710 = or i32 %j.19, 1
--> {(1 + (4 * %l)),+,2}<nsw><%for.body81>
Scev could only analyze the 'or' as it knew %j.19 is a multiple of 2. This
information was not available after the first scop was code generated (or
independent-blocks was run on it) and SCEV could not derive a precise SCEV
expression any more. This means we could not any more code generate this SCoP.
My current understanding is that there is always the risk that an earlier code
generation change invalidates later scops. As the example we have seen here is
difficult to avoid, we use this occasion to guard us against all such
invalidations.
This patch "solves" this issue by verifying right before we start working on
a detected scop, if this scop is in fact still valid. This adds a certain
overhead. However the verification we run is anyways very fast and secondly
it is only run on detected scops. So the overhead should not be very large. As
a later optimization we could detect scops only on demand, such that we need
to run scop-detections always only a single time.
This should fix the single last failure in the LLVM test-suite for the new
scev-based code generation.
llvm-svn: 201593
In rare cases, a region R which is itself not valid has an indirect child region
that is valid. When R becomes part of a valid region by expansion of another
region, then all children of R have to be erased from the set of valid regions.
This patch ensures that indirect children are erased in addition to direct
children.
Contributed-by: Armin Groesslinger <armin.groesslinger@uni-passau.de>
Tobias: I added a reduced test case and adjusted the logic of the patch to
only recurse until the first child is found.
llvm-svn: 200411
Verification of base addresses is difficult as the independent blocks pass may
introduce aliasing that was not there during scop detection. As a midterm
solution -polly-codegen-scev will remove the need for the independent blocks
pass. For now, we do not verify at compile time that the independent blocks pass
does not make the base addresses loop invariant. Disabling this just removes
one of the multiple safety layers we have. We still can check for correctness
in our regression tests.
llvm-svn: 200315
Array base addresses need to be invariant in the region considered. The base
address has to be computed outside the region, or, when it is computed inside,
the value must not change with the iterations of the loops. For example, when a
two-dimensional array is represented as a pointer to pointers the base address
A[i] in an access A[i][j] changes with i; therefore, such regions have to be
rejected.
Contributed by: Armin Größlinger <armin.groesslinger@uni-passau.de>
llvm-svn: 200314
This fixes a crash that appeared when generating dotty graphs for functions
without loops (for which we do not calculate polyhedral information).
llvm-svn: 198364
We now report the following:
$ polly-clang -O3 -mllvm -polly -mllvm -polly-report test.c -c \
-gline-tables-only
note: Polly detected an optimizable loop region (scop) in function 'foo'
test.c:2: Start of scop
test.c:3: End of scop
note: Polly detected an optimizable loop region (scop) in function 'bar'
test.c:9: Start of scop
test.c:13: End of scop
llvm-svn: 197558
String operations resulted by raw_string_ostream in the INVALID macro can lead
to significant compile-time overhead when compiling large size source code.
This is because raw_string_ostream relies on TypeFinder class, whose
compile-time cost increases as the size of the module increases. This patch
targets to ensure that it only track detection failures if actually needed.
In this way, we can avoid expensive string operations in normal execution.
With this patch file, the relative compile-time cost of Polly-detect pass does
not increase even when compiling very large size source code.
Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 187102
When a region header is part of a loop, then all entering edges of this region
should not come from the loop but outside the region. Otherwise, the loop may be
only partially part of the region, which would cause troubles in handling
induction variables.
Currently, we can only model induction variables that are either fully part of
the scop (loop induction variable) or induction variables that are scop-
invariant (parameter). A loop that is only partially part of the
scop causes troubles, as there is no good way to handle the induction
variable in the independent blocks pass.
Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 183800
Use the new cl::OptionCategory support to move the Polly options into a separate
option category. The aim is to hide most options and show by default only the
options a user needs to influence '-O3 -polly'. The available options probably
need some care, but here is the current status:
Polly Options:
Configure the polly loop optimizer
-enable-polly-openmp - Generate OpenMP parallel code
-polly - Enable the polly optimizer (only at -O3)
-polly-no-tiling - Disable tiling in the scheduler
-polly-only-func=<function-name> - Only run on a single function
-polly-report - Print information about the activities
of Polly
-polly-vectorizer - Select the vectorization strategy
=none - No Vectorization
=polly - Polly internal vectorizer
=unroll-only - Only grouped unroll the vectorize
candidate loops
=bb - The Basic Block vectorizer driven by
Polly
llvm-svn: 181295
Regions that have multiple entry edges are very common. A simple if condition
yields e.g. such a region:
if
/ \
then else
\ /
for_region
This for_region contains two entry edges 'then' -> 'for_region' and 'else' -> 'for_region'.
Previously we scheduled the RegionSimplify pass to translate such regions into
simple regions. With this patch, we now support them natively when the region is
in -loop-simplify form, which means the entry block should not be a loop header.
Contributed by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 179586
Regions that have multiple exit edges are very common. A simple if condition
yields e.g. such a region:
if
/ \
then else
\ /
after
Region: if -> after
This regions contains the bbs 'if', 'then', 'else', but not 'after'. It has
two exit edges 'then' -> 'after' and 'else' -> 'after'.
Previously we scheduled the RegionSimplify pass to translate such regions into
simple regions. With this patch, we now support them natively.
Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 179159
Fix inspired from c2d4a0627e95c34a819b9d4ffb4db62daa78dade.
Given the following code
for (i = 0; i < 10; i++) {
;
}
S: A[i] = 0
When translate the data reference A[i] in statement S using scev, we need to
retrieve the scev of 'i' at the location of 'S'. If we do not do this the
scev that we obtain will be expressed as {0,+,1}_for and will reference loop
iterators that do not surround 'S'. What we really want is the scev to be
instantiated to the value of 'i' after the loop. This value is {10}.
This used to crash in:
int loopDimension = getLoopDepth(Expr->getLoop());
isl_aff *LAff = isl_aff_set_coefficient_si(
isl_aff_zero_on_domain(LocalSpace), isl_dim_in, loopDimension, 1);
(gdb) p Expr->dump()
{8,+,8}<nw><%do.body>
(gdb) p getLoopDepth(Expr->getLoop())
$5 = 0
isl_space *Space = isl_space_set_alloc(Ctx, 0, NbLoopSpaces);
isl_local_space *LocalSpace = isl_local_space_from_space(Space);
As we are trying to create a memory access in a stmt that is outside all loops,
LocalSpace has 0 dimensions:
(gdb) p NbLoopSpaces
$12 = 0
(gdb) p Statement.BB->dump()
if.then: ; preds = %do.end
%0 = load float* %add.ptr, align 4
store float %0, float* %q.1.reg2mem, align 4
br label %if.end.single_exit
and so the scev for %add.ptr should be taken at the place where it is used,
i.e., it should be the value on the last iteration of the do.body loop, and not
"{8,+,8}<nw><%do.body>".
llvm-svn: 179148
After this commit, polly is clang-format clean. This can be tested with
'ninja polly-check-format'. Updates to clang-format may change this, but the
differences will hopefully be both small and general improvements to the
formatting.
We currently have some not very nice formatting for a couple of items, DEBUG()
stmts for example. I believe the benefit of being clang-format clean outweights
the not perfect layout of this code.
llvm-svn: 177796
We now detect scops without a canonical induction variable and can generate a
polyhedral representation for them. There was no modification necessary to
code generate these scops.
llvm-svn: 177643
When using the scev based code generation, we now do not rely on the presence
of a canonical induction variable any more. This commit prepares the path to
(conditionally) disable the induction variable canonicalization pass.
llvm-svn: 177548
We now show the all members of the alias set that may couse possible aliasing.
In case a alias set member is not a named instruction (unnamed instructions or
constant expressions), we show the expression itself.
This improves our error message
from:
Possible aliasing for value: .reg2mem
to:
Possible aliasing: ".reg2mem",
"[0 x double]* inttoptr (i64 47255179264 to [0 x double]*)
llvm-svn: 174329
We fix the following formatting problems found by clang-format:
- 80 cols violations
- Obvious problems with missing or too many spaces
- multiple new lines in a row
clang-format suggests many more changes, most of them falling in the following
two categories:
1) clang-format does not at all format a piece of code nicely
2) The style that clang-format suggests does not match the style used in
Polly/LLVM
I consider differences caused by reason 1) bugs, which should be fixed by
improving clang-format. Differences due to 2) need to be investigated closer
to understand the cause of the difference and the solution that should be taken.
llvm-svn: 171241
If the flags '-polly-report -g' are given, we print file name and line numbers
for the beginning and end of all detected scops.
linear-algebra/kernels/gemm/gemm.c:23: Scop start
linear-algebra/kernels/gemm/gemm.c:42: Scop end
linear-algebra/kernels/gemm/gemm.c:77: Scop start
linear-algebra/kernels/gemm/gemm.c:82: Scop end
llvm-svn: 167235
Cast instruction do not have side effects and can consequently be part of a
scop. We special cased them earlier, as they may be problematic within array
subscripts or loop bounds. However, the scalar evolution validator already
checks for them such that there is no need to also check the instructions within
the basic blocks. Checking them is actually overly conservative as the precence
of casts may invalidate a scop, even though scalar evolution is not influenced
by it.
llvm-svn: 160261
In case we can not analyze an access function, we do not discard the SCoP, but
assume conservatively that all memory accesses that can be derived from our base
pointer may be accessed.
Patch provided by: Marcello Maggioni <hayarms@gmail.com>
llvm-svn: 146972
This does not work reliable and is probably not needed. I accidentally changed
this in this recent commit:
commit a0bcd63c6ffa81616cf8c6663a87588803f7d91c
Author: grosser <grosser@91177308-0d34-0410-b5e6-96231b3b80d8>
Date: Thu Nov 10 12:47:21 2011 +0000
ScopDetect: Use INVALID macro to fail in case of aliasing
This simplifies the code and also makes the error message available to the
graphviz scop viewer.
git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@144284
llvm-svn: 144286
address is part of the access function. Also remove unused special cases that
were necessery when the base address was still contained in the access function
llvm-svn: 144280
Previously we allowed in access functions only a single SCEVUnknown, which later
became the base address. We now use getPointerBase() to derive the base address
and all remaining unknowns are handled as parameters. This allows us to handle
cases like A[b+c];
llvm-svn: 144278
This check was necessary because of the use AffineSCEVIterator in TempScopInfo.
As we removed this use recently it is not necessary any more.
llvm-svn: 144228
Instead of using TempScop to find parameters, we detect them directly
on the SCEV. This allows us to remove the TempScop parameter detection
in a subsequent commit.
This fixes a bug reported by Marcello Maggioni <hayarms@gmail.com>
llvm-svn: 144087
We currently run the old memory access checker in parallel, as we would
otherwise fail in TempScop because of currently unsupported functions. We will
remove the old memory access checker as soon as TempScop is fixed.
llvm-svn: 143654
The SCEV Validator is used to check if the bound of a loop can be translated
into a polyhedral constraint. The new validator is more general as the check
used previously and e.g. allows bounds like 'smax 1, %a'. At the moment, we
only allow signed comparisons. Also, the new validator is only used to verify
loop bounds. Memory accesses are still handled by the old validator.
llvm-svn: 143576
Andreas Simbuerger