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
Given the following code
for (i = 0; i < 10; i++) {
;
}
S: A[i] = 0
When code generating S using scev based code generation, 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' and that we consequently do not know how to code
generate. What we really want is the scev to be instantiated to the value of 'i'
after the loop. This value is {10} and it can be code generated without
troubles.
llvm-svn: 177777
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
When doing SCEV based code generation, we ignore instructions calculating values
that are fully defined by a SCEV expression. The values that are calculated by
this instructions are recalculated on demand.
This commit improves the check to verify if certain instructions can be ignored
and recalculated on demand.
llvm-svn: 177313
In my previous commits I failed to realise that my new requires lines fully
disabled these tests. We now properly check if we are in an asserts build and
only disable the tests if assertions are not available.
Reported-by: Sean Silva <silvas@purdue.edu>
llvm-svn: 176900
This fixes issues caused by the following commit:
r176733 | jvoung | 2013-03-08 17:56:31 -0500
Disable statistics on Release builds and move tests that depend on -stats.
Reported by: Jack Howarth <howarth@bromo.med.uc.edu>
llvm-svn: 176856
We need to remove one dimension. Any is correct as long as it exists. We have
choosen for whatever reason the dimension #dims - 2. This is incorrect if
there is just one dimension. For CLooG this case did never happen. For isl
however, the case can happen and causes undefined behavior including crashes.
We choose now always the last dimension #dims - 1. We could have choosen
dimension '0' but the last dimension is what we remove conceptionally in the
algorithm, so it seems better to actually program it that way.
While at it remove another piece of undefined behavior.
llvm-svn: 174894
Similar to LLVM we now follow the policy of only having LLVM-IR level tests in
the Polly test suite. Testing for miscompilation of larger programs should be
done with the llvm test suite.
llvm-svn: 167255
Instead of calculating exact value (flow) dependences, it is also possible to
calculate memory based dependences. Sometimes memory based dependences are a lot
easier to calculate. To evaluate the benefits, we add an option to calculate
memory based dependences (use -polly-value-dependences=false).
llvm-svn: 167251
The detection of values that need to be copied in to the generated OpenMP
subfunction also detects the array base addresses needed in the SCoP. Hence, it
is not necessary to unconditionally copy all the base addresses to the generated
function.
Test cases are modified to reflect this change. Arrays which are global
variables do not occur in the struct passed to the subfunction anymore. A test
case for base address copy-in is added in copy_in_array.{c,ll}.
Committed with slight modifications
Contributed by: Armin Groesslinger <armin.groesslinger@uni-passau.de>
llvm-svn: 167215
In addition to the arrays and clast variables a SCoP statement may also refer to
values defined before the SCoP or to function arguments. Detect these values and
add them to the set of values passed to the function generated for OpenMP
parallel execution of a clast.
Committed with additional test cases and some refactoring.
Contributed by: Armin Groesslinger <armin.groesslinger@uni-passau.de>
llvm-svn: 167214
When generating OpenMP or GPGPU code the original ValueMap and ClastVars must be
kept. We already recovered the original ClastVars by reverting the changes, but
we did not keep the content of the ValueMap. This patch keeps now an explicit
copy of both maps and restores them after generating OpenMP or GPGPU code.
This is an adapted version of a patch contributed by:
Armin Groesslinger <armin.groesslinger@uni-passau.de>
llvm-svn: 167213
On Linux there is no difference between shared modules and shared libaries, both
are '.so' files. However, on darwin only shared modules are '.so' files. Shared
libraries have the '.dynlib' suffix.
Fix test cases on darwin by expecting a shared module suffix for Polly instead
of a shared library suffix.
This fixes PR14135
Reported by: Jack Howarth <howarth@bromo.med.uc.edu>
llvm-svn: 166402
The bug was within isl. To fix it, we simply update the isl version that
is used by Polly. We still have some changes within Polly to be able to
write a proper test case.
Reported-by: Sameer Sahasrabuddhe <Sameer.Sahasrabuddhe@amd.com>
llvm-svn: 166021
Previously isl always generated '<=' or '>='. However, in many cases '<' or '>'
leads to simpler code. This commit updates isl and adds the relevant code
generation support to Polly.
llvm-svn: 166020
At the moment we can handle such arrays only by conservatively assuming that
each access to such an array may touch any element in the array. It would be
great if we could improve Polly/LLVM at some point, such that we can
recover the multi-dimensionality of the accesses.
llvm-svn: 163619
This ensures that the isl sets/maps we operate on have the same parameter
dimensions. Operations on objects with different parameter dimensions are not
allow and trigger assertions.
llvm-svn: 163618
Translate the selected parallel loop body into a ptx string and run it with the
cuda driver API. We limit this preliminary implementation to target the
following special test cases:
- Support only 2-dimensional parallel loops with or without only one innermost
non-parallel loop.
- Support write memory access to only one array in a SCoP.
The patch was committed with smaller changes to the build system:
There is now a flag to enable gpu code generation explictly. This was required
as we need the llvm.codegen() patch applied on the llvm sources, to compile this
feature correctly. Also, enabling gpu code generation does not require cuda.
This requirement was removed to allow 'make polly-test' runs, even without an
installed cuda runtime.
Contributed by: Yabin Hu <yabin.hwu@gmail.com>
llvm-svn: 161239
I did not take into account, that this patch fails to compile without the
llvm.codegen patch applied. This breaks buildbots.
I revert this until we found a solution to commit this without buildbots
complaining.
This reverts commit cb43ab80e94434e780a66be3b9a6ad466822fe33.
llvm-svn: 160165
Translate the selected parallel loop body into a ptx string and run it
with cuda driver API. We limit this preliminary implementation to
target the following special test cases:
- Support only 2-dimensional parallel loops with or without only one
innermost non-parallel loop.
- Support write memory access to only one array in a SCoP.
Contributed by: Yabin Hu <yabin.hwu@gmail.com>
llvm-svn: 160164
Derive the maximal and minimal values of a parameter from the type it has. Add
this information to the scop context. This information is needed, to derive
optimal types during code generation.
llvm-svn: 157245
This is an incomplete implementation of the SCEV based code generation.
When finished it will remove the need for -indvars -enable-iv-rewrite.
For the moment it is still disabled. Even though it passes 'make polly-test',
there are still loose ends especially in respect of OpenMP code generation.
llvm-svn: 155717
This fixes two crashes that appeared in case of:
- A load of a non vectorizable type (e.g. float**)
- An instruction that is not vectorizable (e.g. call)
llvm-svn: 154586
Grouped unrolling means that we unroll a loop such that the different instances
of a certain statement are scheduled right after each other, but we do
not generate any vector code. The idea here is that we can schedule the
bb vectorizer right afterwards and use it heuristics to decide when
vectorization should be performed.
llvm-svn: 154251
To avoid overflows we still use a larger type (i64) while calculating the value
of the old ivs. However, we truncate the result to the type of the old iv when
providing it to the new code.
A corresponding test case is added to the polly test suite. Also, a failing test
case is fixed.
This fixes PR12311.
Contributed by: Tsingray Liu <tsingrayliu@gmail.com>
llvm-svn: 153952
When deriving new values for the statements of a SCoP, we assumed that parameter
values are constant within the SCoP and consquently do not need to be rewritten.
For OpenMP code generation this assumption is wrong, as such values are not
available in the OpenMP subfunction and consequently also may need to be
rewritten.
Committed with some changes.
Contributed-By: Johannes Doerfert <s9jodoer@stud.uni-saarland.de>
llvm-svn: 153838
This also adds support for modifiable write accesses (until now only read
accesses where supported). We currently do not derive an exact type for the
expression, but assume that i64 is good enough. This will be improved in future
patches.
Contributed by: Yabin Hu <yabin.hwu@gmail.com>
llvm-svn: 153319
We currently do not support pointer types in affine expressions. Hence, we
disallow in the SCoP detection. Later we may decide to add support for them.
This fixes PR12277
Reported-By: Sebastian Pop <sebpop@gmail.com>
llvm-svn: 152928
This also fixes UMax where we did not correctly keep track of the parameters.
Fixes PR12275.
Reported-By: Sebastian Pop <sebpop@gmail.com>
llvm-svn: 152913
The FinalRead statement represented a virtual read that is executed after the
SCoP. It was used when we verified the correctness of a schedule by checking if
it yields the same FLOW dependences as the original code. This is only works, if
we have a final read that reads all memory at the end of the SCoP.
We now switched to just checking if a schedule does not introduce negative
dependences and also consider WAW WAR dependences. This restricts the schedules
a little bit more, but we do not have any optimizer that would calculate a more
complex schedule. Hence, for now final reads are obsolete.
llvm-svn: 152319
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
Parameters can be complex SCEV expressions, but they can also be single scalar
values. If a parameters is such a simple scalar value and the value is named,
use this name to name the isl parameter dimensions.
llvm-svn: 144641
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
It may happen that we generate the code of a basic block from the original
scop is code generated several times. The new naming scheme reduces confusing
that earlier appeared as the version numbers of the new basic blocks could
have been interpreted as part of the name of the original basic block.
llvm-svn: 139092
Due to the recent introduction of isl_id, parameters need now always to be
aligned. This was not yet taken care of in the code path of vectorization and
dependence analysis.
llvm-svn: 138555
I am planning to eliminate the TempScopInfo pass. To simplify this I remove
some features that may later be added to the ScopInfo pass.
The interchange pass is currently strongly tested and furthermore ment to be
replaced by the general scheduling optimizer. Reductions itself can later
be added easily.
llvm-svn: 138219
Code is generated for a simple access function change imported
from JSCOP file. An access of A[i] is changed to A[0]. The code
for A[0] is generated directly without refering to isl function calls.
llvm-svn: 136789
Instead of deleting the old code, keep it on the side in an if-branch. It will
either be deleted by the dead code elimination or we can use it as fallback.
llvm-svn: 131352
Sebastian Pop