This allows us to delinerize code such as:
A[][n]
for (i
for (j
A[i][n-j-1] = ...
which would previously have been delinearize to an access A[i+1][-j-1].
To recover the correct access we apply the piecewise expression:
{ A[i][j] -> A[i-1][i+N]: i < 0; A[i][j] -> A[i][i]: i >= 0}
This approach generalizes to higher dimensions.
llvm-svn: 233566
This will strip the constant factor of a parameter befor we add it to
the SCoP. As a result the access functions are simplified, e.g., for
the attached test case.
llvm-svn: 233501
The performance test case just committed was the last open issue I was aware of.
We enable this by default to increase test coverage and to possibly trigger
reports of issues yet unknown.
llvm-svn: 231590
The new Dependences struct in the DependenceInfo holds all information
that was formerly part of the DependenceInfo. It also provides the
same interface for the user to access this information.
This is another step to a more general ScopPass interface that does
allow multiple SCoPs to be "in flight".
llvm-svn: 231327
We rename the Dependences pass to DependenceInfo as a first step to a
caching pass policy. The new DependenceInfo pass will later provide
"Dependences" for a SCoP.
To keep consistency the test folder is renamed too.
llvm-svn: 231308
If a scalar was defined and used only in a non-affine subregion we do
not need to model the accesses. However, if the scalar was defined
inside the region and escapes the region we have to model the access.
The same is true if the scalar was defined outside and used inside the
region.
llvm-svn: 230960
With the patches r230325, r230329 and r230340 we can handle non-affine
control flow in (loop-free) subregions. As all LLVM test-suite tests pass and
we get ~20% more non-trivial SCoPs, we activate it now by default.
llvm-svn: 230624
This allows us to model non-affine regions in the SCoP representation.
SCoP statements can now describe either basic blocks or non-affine
regions. In the latter case all accesses in the region are accumulated
for the statement and write accesses, except in the entry, have to be
marked as may-write.
Differential Revision: http://reviews.llvm.org/D7846
llvm-svn: 230329
With this patch we allow the SCoP detection to detect regions as SCoPs
which have non-affine control flow inside. All non-affine regions are
tracked and later accessible to the ScopInfo.
As there is no real difference, non-affine branches as well as
floating point branches are covered (and both called non-affine
control flow). However, the detection is restricted to
overapproximate only loop free regions.
llvm-svn: 230325
Scops that only read seem generally uninteresting and scops that only write are
most likely initializations where there is also little to optimize. To not
waste compile time we bail early.
Differential Revision: http://reviews.llvm.org/D7735
llvm-svn: 229820
Alias checks might become costly if there are divisions that complicate the
description of the accessed locations. By overaproximating them we get fairly
accurate results without the huge compile time cost.
llvm-svn: 229252
This allows us to skip ast and code generation if we did not optimize
a SCoP and will not generate parallel or alias annotations. The
initial heuristic to exit is simple but allows improvements later on.
All failing test cases have been modified to disable early exit, thus
to keep their coverage.
Differential Revision: http://reviews.llvm.org/D7254
llvm-svn: 228851
These write are important as they will force the scheduling and code
generation of an otherwise trivial statement and also impose an order of
execution needed to guarantee the correct final value for a scalar in a loop.
Added test case modeled after ClamAV/clamscan.
llvm-svn: 228847
This change has two main purposes:
1) We do not use a static interface to hide an object we create and
destroy for every basic block we copy.
2) We allow the BlockGenerator to store information between calls to
the copyBB method. This will ease scalar/phi code generation
later on.
While a lot of method signatures were changed this should not cause
any real behaviour change.
Differential Revision: http://reviews.llvm.org/D7467
llvm-svn: 228443
This allows us to model PHI nodes in the polyhedral description
without demoting them. The modeling however will result in the
same accesses as the demotion would have introduced.
Differential Revision: http://reviews.llvm.org/D7415
llvm-svn: 228433
Duncan P. N. Exon Smith