Commit Graph

11 Commits

Author SHA1 Message Date
Tobias Grosser 0483271662 Add support for two-level tiling
By default we only use one level of tiling for loops, but in general tiling
for multiple levels is trivial for us. Hence, we add a set of options that
allow people to play with a second level of tiling. If this is profitable for
some cases we can work on heuristics that allow us to identify these cases
and use two-level tiling for them.

llvm-svn: 245563
2015-08-20 13:45:02 +00:00
Tobias Grosser 161c9081e5 Do not use negative option name
Instead of -polly-no-tiling, we use -polly-tiling=false to disable tiling.

llvm-svn: 245423
2015-08-19 08:22:06 +00:00
Tobias Grosser 808cd69a92 Use schedule trees to represent execution order of statements
Instead of flat schedules, we now use so-called schedule trees to represent the
execution order of the statements in a SCoP. Schedule trees make it a lot easier
to analyze, understand and modify properties of a schedule, as specific nodes
in the tree can be choosen and possibly replaced.

This patch does not yet fully move our DependenceInfo pass to schedule trees,
as some additional performance analysis is needed here. (In general schedule
trees should be faster in compile-time, as the more structured representation
is generally easier to analyze and work with). We also can not yet perform the
reduction analysis on schedule trees.

For more information regarding schedule trees, please see Section 6 of
https://lirias.kuleuven.be/handle/123456789/497238

llvm-svn: 242130
2015-07-14 09:33:13 +00:00
Tobias Grosser 02cf69a6ed Make -polly-no-tiling work again
llvm-svn: 234125
2015-04-05 21:52:21 +00:00
Tobias Grosser 4f6bceface Do not scale tile loops
We now generate tile loops as:

 for (int c1 = 0; c1 <= 47; c1 += 1)
   for (int c2 = 0; c2 <= 47; c2 += 1)
     for (int c3 = 0; c3 <= 31; c3 += 1)
       for (int c4 = 0; c4 <= 31; c4 += 4)
         #pragma simd
         for (int c5 = c4; c5 <= c4 + 3; c5 += 1)
           Stmt_for_body3(32 * c1 + c3, 32 * c2 + c5);

instead of

 for (int c1 = 0; c1 <= 1535; c1 += 32)
   for (int c2 = 0; c2 <= 1535; c2 += 32)
     for (int c3 = 0; c3 <= 31; c3 += 1)
       for (int c4 = 0; c4 <= 31; c4 += 4)
         #pragma simd
         for (int c5 = c4; c5 <= c4 + 3; c5 += 1)
           Stmt_for_body3(c1 + c3, c2 + c5);

Run-time performance-wise this makes little difference, but this gives a large
reduction in compile time (10-30% on 17 LNT benchmarks). Apparently the isl
AST generator is not yet very efficient in generating the latter.

llvm-svn: 233675
2015-03-31 07:52:36 +00:00
Tobias Grosser bbb4cec2e8 Use schedule trees to perform post-scheduling transformations
Replacing the old band_tree based code with code that is based on the new
schedule tree [1] interface makes applying complex schedule transformations a lot
more straightforward. We now do not need to reason about the meaning of flat
schedules, but can use a more straightforward tree structure. We do not yet
exploit this a lot in the current code, but hopefully we will be able to do so
soon.

This change also allows us to drop some code, as isl now provides some higher
level interfaces to apply loop transformations such as tiling.

This change causes some small test case changes as isl uses a slightly different
way to perform loop tiling, but no significant functional changes are intended.

[1] http://impact.gforge.inria.fr/impact2014/papers/impact2014-verdoolaege.pdf

llvm-svn: 232911
2015-03-22 12:06:39 +00:00
Tobias Grosser 9715b7c592 Add forgotten 'FileCheck' to tiling test cases
These test cases did not verify the CHECK lines at all. We add the FileCheck
and also fix some broken CHECK lines. Being here, we extend the checks to
cover the whole loop structure.

llvm-svn: 232710
2015-03-19 07:39:34 +00:00
David Blaikie bad3ff207f Update Polly tests to handle explicitly typed gep changes in LLVM
llvm-svn: 230784
2015-02-27 19:20:19 +00:00
Tobias Grosser d1e33e7061 ScopDetection: Only detect scops that have at least one read and one write
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
2015-02-19 05:31:07 +00:00
Tobias Grosser e7e33ba13a Always pipe in test files
In Polly we used to have a mix of test cases, some that used 'opt %s' and others
that used 'opt < %s'. We now change all to use 'opt < %s'. Piping in test files
is preferable as it does prevent temporary files to be written to disk. This
brings us in line with what is usus in LLVM.

llvm-svn: 216816
2014-08-30 09:15:04 +00:00
Johannes Doerfert c3958b214c Added option for n-dimensional rectangular tiling
+ CL-option --polly-tile-sizes=<int,...,int>
  The i'th value is used as a tile size for dimension i, if
  there is no i'th value, the value of --polly-default-tile-size is
  used

+ CL-option --polly-default-tile-size=int
  Used if no tile size is given for a dimension i

+ 3 Simple testcases

llvm-svn: 209753
2014-05-28 17:21:02 +00:00