hanchenye-llvm-project/polly
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
..
autoconf Drop libpluto support 2015-03-30 17:54:01 +00:00
cmake Drop libpluto support 2015-03-30 17:54:01 +00:00
include Drop some CLooG leftovers 2015-03-30 17:56:50 +00:00
lib Do not scale tile loops 2015-03-31 07:52:36 +00:00
test Do not scale tile loops 2015-03-31 07:52:36 +00:00
tools Ensure the functions in our GPURuntime are visible 2015-03-10 20:23:14 +00:00
utils Remove isl/cloog build scripts 2015-02-15 11:19:20 +00:00
www Delete some leftovers from scoplib 2015-03-30 17:55:40 +00:00
.arcconfig Added arcanist (arc) unit test support 2014-09-08 19:30:09 +00:00
.arclint Added arcanist linters and cleaned errors and warnings 2014-08-18 00:40:13 +00:00
.gitattributes gitattributes: .png and .txt are no text files 2013-07-28 09:05:20 +00:00
.gitignore Add test/lit.site.cfg to .gitignore 2014-09-07 15:03:30 +00:00
CMakeLists.txt Drop libpluto support 2015-03-30 17:54:01 +00:00
CREDITS.txt Add myself to the credits 2014-08-10 03:37:29 +00:00
LICENSE.txt Update the copyright credits -- Happy new year 2014! 2014-01-01 08:27:31 +00:00
Makefile
Makefile.common.in
Makefile.config.in Drop libpluto support 2015-03-30 17:54:01 +00:00
README
configure Drop libpluto support 2015-03-30 17:54:01 +00:00

README

Polly - Polyhedral optimizations for LLVM
-----------------------------------------
http://polly.llvm.org/

Polly uses a mathematical representation, the polyhedral model, to represent and
transform loops and other control flow structures. Using an abstract
representation it is possible to reason about transformations in a more general
way and to use highly optimized linear programming libraries to figure out the
optimal loop structure. These transformations can be used to do constant
propagation through arrays, remove dead loop iterations, optimize loops for
cache locality, optimize arrays, apply advanced automatic parallelization, drive
vectorization, or they can be used to do software pipelining.