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
Restricting Polly to -O3 does not make a lot of sense as it is opt-in anyway
and users who specifically request it should get it. If this causes performance
problems we should rather address them by scheduling the right cleanup passes
then just prevent the user from trying.
Also restricting Polly to -O3 made bugpoint not work with the -O3 flag and polly
enabled.
llvm-svn: 200208
This is not only not necessary, but in case -03 changes this can actually
cause arbitrarily failing test cases such as, e.g., a recent change by Chandler
that caused -O3 to unroll the loop body, which made the loop we wanted to
detect disappear and consequently this test case fail.
llvm-svn: 200204
Count the number of computational steps that have been used to solve the
dependence problem and abort in case we reach the "compute-out". This ensures we
do not hang forever in cases the dependence problem is too difficult to solve.
There is just a single case in the LLVM test-suite that runs into the
compute-out. Even in this case, we can probably coalesce some of the parameters
(i32 b, i32 b zext i64, ...) to simplify the problem enough to not hit the
compute out. However, for now we set the compute out in place to address the
general issue. The compute out was choosen such that it stops on a recent laptop
after about 8 seconds.
llvm-svn: 200156
This includes the following very useful isl commit:
commit d962967ab42323ea5ca0398956fbff6a98c782fa
Author: Sven Verdoolaege <skimo@kotnet.org>
Date: Wed Dec 18 12:05:32 2013 +0100
allow the user to impose a bound on the number of low-level operations
This should allow the user to deterministically limit the effort spent on a
computation.
llvm-svn: 200155
This removes the last isl_int dependency in the default build. There are
still some in OpenScop and Scoplib. For those isl-0.12.2 still needs to be used.
llvm-svn: 199585
This brings in isl_val support from cloog and, most importantly the following
isl commit:
commit d962967ab42323ea5ca0398956fbff6a98c782fa
Author: Sven Verdoolaege <skimo@kotnet.org>
Date: Wed Dec 18 12:05:32 2013 +0100
allow the user to impose a bound on the number of low-level operations
This should allow the user to deterministically limit the effort spent on a
computation.
llvm-svn: 199582
This ModulePass schedules the set of Polly canonicalization passes. It is a
debugging tool that can be used to preoptimize .ll files for Polly processing.
llvm-svn: 198376
Also the code makes the impression this was happening, shouldEnablePolly()
always returns false for optlevel equal to zero. This was previously different,
but was accidentally changed by a commit a couple of months ago. As this
behavior was mainly a debugging tool and adding this to clang never really made
sense, we just remove the last traces.
llvm-svn: 198370
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
Further:
o ensure that the header is properly readable even on smaller screen sizes.
o Shorten the table of contents of the documentation section.
llvm-svn: 197794
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
Tobias Grosser