Commit Graph

184 Commits

Author SHA1 Message Date
Tobias Grosser 356faa8f09 Dead code elimination: Schedule another approximative step before actual DCE
In 'obsequi' we have a scop in which the current dead code elimination works,
but the generated code is way too complex. To avoid this trouble (and to not
disable the DCE entirely) we add an additional approximative step before
the actual dead code elimination. This should fix one of the two current
nightly-test issues.

Polly could be improved to handle 'obsequi' by teaching it to introduce only a
single parameter for (%1 and zext %1) which halves the number of parameters and
allows polly to derive a simpler representation for the set of live iterations.
However, this needs some time to investigate.

I will commit a test case as soon as we have a reduced one.

llvm-svn: 202010
2014-02-24 08:52:20 +00:00
Tobias Grosser 472d3b7037 codegen: Update LoopInfo correctly
Add the 'polly.start' basic block to the loop that surrounds the scop we just
codegenerate.

This fixes PR13441

llvm-svn: 202000
2014-02-24 00:50:49 +00:00
Tobias Grosser 38c36ea18e Do not fail in case we do not have valid dependences
In case we do not have valid dependences, we do not run dead code elimination or
the schedule optimizer. This fixes an infinite loop in the dead code
elimination (PR12110).

llvm-svn: 201982
2014-02-23 15:15:44 +00:00
Tobias Grosser 88640d2b47 Use -polly-codegen-isl in isl-codegen test
Reported-by: Sebastian Pop <spop@codeaurora.org>
llvm-svn: 201902
2014-02-21 23:08:54 +00:00
Tobias Grosser 817d51dd1b DCE: Switch to hybrid precise-unprecise analysis
Instead of giving a choice between a precise (but possibly very complex)
analysis and an approximative analysis we now use a hybrid approach which uses N
precise steps followed by one approximating step. The precision of the analysis
can be changed by increasing N. With a default of 'N' = 2, we get fully precise
results for our current test cases and should not run into performance problems
for more complex test cases. We can adjust this value when we got more
experience with this dead code elimination.

llvm-svn: 201888
2014-02-21 20:51:46 +00:00
Tobias Grosser 030237d0ff Codegen: Do not crash when seeing debug intrinsics
We now skip the debug intrinsics which is a lot better than crashing due to
uncopied metadata references. We should step by step investigate which debug
intrinsics we can copy without trouble.

We still keep the debug location metadata.

llvm-svn: 201860
2014-02-21 15:06:05 +00:00
Tobias Grosser 37eb422f69 Add polyhedral dead code elimination.
This pass eliminates loop iterations that compute results that are not used
later on. This can help e.g. in D, where the default zero-initialization is
often unnecessary if right after new values are assigned to an array.

Contributed-by: Peter Conn <conn.peter@gmail.com>
llvm-svn: 201817
2014-02-20 21:43:54 +00:00
Tobias Grosser d6aafa7c2e Do not track location of scalar dependences in ScopInfo
We do not have a use for this information at the moment. If we need this at some
point, the "instruction -> access" mapping needs to be enhanced as a single
instruction could then possibly perform multiple accesses.

This patch allows us to build the polyhedral information for scops with scalar
dependences.

llvm-svn: 201815
2014-02-20 21:29:09 +00:00
Tobias Grosser a1689937ba Check scops a second time before working on them
In rare cases the modification of one scop can effect the validity of other
scops, as code generation of an earlier scop may make the scalar evolution
functions derived for later scops less precise. The example that triggered this
patch was a scop that contained an 'or' expression as follows:

  %add13710 = or i32 %j.19, 1
    -->  {(1 + (4 * %l)),+,2}<nsw><%for.body81>

Scev could only analyze the 'or' as it knew %j.19 is a multiple of 2. This
information was not available after the first scop was code generated (or
independent-blocks was run on it) and SCEV could not derive a precise SCEV
expression any more. This means we could not any more code generate this SCoP.
My current understanding is that there is always the risk that an earlier code
generation change invalidates later scops.  As the example we have seen here is
difficult to avoid, we use this occasion to guard us against all such
invalidations.

This patch "solves" this issue by verifying right before we start working on
a detected scop, if this scop is in fact still valid. This adds a certain
overhead. However the verification we run is anyways very fast and secondly
it is only run on detected scops. So the overhead should not be very large. As
a later optimization we could detect scops only on demand, such that we need
to run scop-detections always only a single time.

This should fix the single last failure in the LLVM test-suite for the new
scev-based code generation.

llvm-svn: 201593
2014-02-18 18:49:49 +00:00
Tobias Grosser 933edd04af IndependentBlocks: Do not assert for PHI nodes outside of scops
There does not seem to be a reason that we can not support PHI nodes outside of
the scop that reference values within the SCoP. Or at least, the attached test
case seems to do the right thing. We remove the assert for now.

llvm-svn: 200427
2014-01-29 23:08:10 +00:00
Tobias Grosser 28a70c543d ScopDetect: Transitively remove all children after region expansion
In rare cases, a region R which is itself not valid has an indirect child region
that is valid. When R becomes part of a valid region by expansion of another
region, then all children of R have to be erased from the set of valid regions.
This patch ensures that indirect children are erased in addition to direct
children.

Contributed-by: Armin Groesslinger <armin.groesslinger@uni-passau.de>

Tobias: I added a reduced test case and adjusted the logic of the patch to
        only recurse until the first child is found.
llvm-svn: 200411
2014-01-29 19:05:30 +00:00
Tobias Grosser 458fb78cfa Check if array base addresses are invariant
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
2014-01-28 12:58:58 +00:00
Tobias Grosser 5b5daab9f1 Add more test cases to check loop invariance of the base pointer.
llvm-svn: 200305
2014-01-28 10:29:17 +00:00
Tobias Grosser 24d7e669b3 Do not test polybench with 'make check-polly'
Those test cases should be tested in the LLVM test suite. For Polly we should
extract regression tests for the individual passes.

llvm-svn: 200206
2014-01-27 10:37:33 +00:00
Tobias Grosser 54646f7fab Remove other unneccessary uses of -O3 in the test suite
The polly test suite is now -O3 clean.

llvm-svn: 200205
2014-01-27 10:37:06 +00:00
Tobias Grosser a7fea8386c Do not run -O3 to canonicalize test case
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
2014-01-27 10:23:12 +00:00
Tobias Grosser b917f47fc4 Dependences: Bound the time dependence calculation is allowed to take
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
2014-01-26 19:38:34 +00:00
Tobias Grosser 0d43646f93 Adjust test case to changed cloog output
llvm-svn: 199587
2014-01-19 11:53:51 +00:00
Tobias Grosser 8519f897e7 Report detected scops using the new diagnostics
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
2013-12-18 10:49:53 +00:00
Tobias Grosser 7b6f9ba572 ScopValidator: smax expressions are no parameters
This fixes PR18155 which is a regression introduced in 152913.

llvm-svn: 196827
2013-12-09 21:51:46 +00:00
Tobias Grosser 7d66a19fe4 test: Remove use of defaultOpts
llvm-svn: 196826
2013-12-09 21:51:31 +00:00
Tobias Grosser 54ee0ba74d IslCodegen: Support for run-time conditions
llvm-svn: 194948
2013-11-17 03:18:25 +00:00
Tobias Grosser e86109f508 ScopInfo: Add support for AssumedContext
When constructing a scop sometimes the exact representation of a statement or
condition would be very complex, but there is a common case which is a lot
simpler, but which is only valid under certain assumptions. The assumed context
records the assumptions taken during the construction of this scop and that need
to be code generated as a run-time test.

At the moment, we do not yet model any assumptions, but only added the
AssumedContext as well as the isl-ast generation support. As a next step,
this needs to be hooked up with the isl code generation.

if (1) /* run-time condition */
  {  /* optimized code */ }
else
  {  /* original code */ }

llvm-svn: 193652
2013-10-29 21:05:49 +00:00
Tobias Grosser 4f8c0877e8 This test case requires assertions
llvm-svn: 192530
2013-10-12 09:15:56 +00:00
Sebastian Pop 20594a842c use -polly-codegen-isl in tests under test/Isl
llvm-svn: 192110
2013-10-07 16:43:04 +00:00
Sebastian Pop 946070f2f0 do not use -polly-cloog in a ScopInfo testcase
llvm-svn: 192109
2013-10-07 16:43:00 +00:00
Tobias Grosser 3613fd7a35 ScopInfo: Correctly handle true/false conditions
This is a modified version of the orignally contributed patch.

Contributed-by: alexandre.isoard@gmail.com
llvm-svn: 190237
2013-09-07 01:54:13 +00:00
Tobias Grosser 815c635cec [CodeGen] Fixup assert fails caused by incorrect LoopInfo update
Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 189764
2013-09-02 16:13:00 +00:00
Daniel Dunbar 2bd59a2cc7 [tests] Update to use lit_config and lit package, as appropriate.
llvm-svn: 188114
2013-08-09 21:54:36 +00:00
Tobias Grosser 22a155a7a6 ScopInfo: add a testcase that share parameters within nested start.
Contributed-by:  Star Tan <tanmx_star@yeah.net>
llvm-svn: 187772
2013-08-06 04:36:45 +00:00
Tobias Grosser e42ddb9ad3 ScopInfo: Split start value from SCEVAddRecExpr to enable parameter sharing.
SCoP invariant parameters with the different start value would deter parameter
sharing. For example, when compiling the following C code:

  void foo(float *input) {
    for (long j = 0; j < 8; j++) {
      // SCoP begin
      for (long i = 0; i < 8; i++) {
        float x = input[j * 64 + i + 1];
        input[j * 64 + i] = x * x;
      }
    }
  }

Polly would creat two parameters for these memory accesses:

    p_0: {0,+,256}
    p_2: {4,+,256}
    [j * 64 + i + 1] => MemRef_input[o0] : 4o0 = p_1 + 4i0
    [j * 64 + i]     => MemRef_input[o0] : 4o0 = p_0 + 4i0

These parameters only differ from start value. To enable parameter sharing,
we split the start value from SCEVAddRecExpr, so they would share a single
parameter that always has zero start value:

    p0: {0,+,256}<%for.cond1.preheader>
    [j * 64 + i + 1] => MemRef_input[o0] : 4o0 = 4 + p_1 + 4i0
    [j * 64 + i]     => MemRef_input[o0] : 4o0 = p_0 + 4i0

Such translation can make the polly-dependence much faster.

Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 187728
2013-08-05 15:14:15 +00:00
Tobias Grosser 96ef078583 Remove '-debug-only' from test case
This flags was not used in the test case, but caused failures when LLVM was
built without debugging. We can savely remove it.

llvm-svn: 187343
2013-07-29 05:35:11 +00:00
Tobias Grosser 6e358c067a TempScop: Actually load Polly in this test case
llvm-svn: 187342
2013-07-29 05:18:09 +00:00
Tobias Grosser 7032ea6f5b Remove second '-analyze' from command line
llvm-svn: 187341
2013-07-29 05:15:33 +00:00
Tobias Grosser 85f7421731 JSONImporter: Free new schedule if found invalid
In case we detect that the schedule the user wants to import is invalid we
refuse it _and_ free the isl_maps containing it.

Another bug found thanks to Rafael.

llvm-svn: 187339
2013-07-29 05:12:01 +00:00
Tobias Grosser 880c52f56a CodeGeneration: Fix double free in vector for
We now use __isl_take to annotate the uses of the isl_set where we got the
memory management wrong.

Thanks to Rafael! His pipefail work hardened our test environment and exposed
this bug nicely.

llvm-svn: 187338
2013-07-29 01:58:07 +00:00
Rafael Espindola cd61afb4ee Use a slightly smaller hammer to make this pass.
When first updating this test I only noticided the first RUN line.

llvm-svn: 187328
2013-07-28 11:13:49 +00:00
Tobias Grosser 25f0342a68 Temporary disable a test until I finished the fix
llvm-svn: 187305
2013-07-27 15:19:57 +00:00
Rafael Espindola 0329bb4fce Looks like this test crashes. Add --crash to not for now.
llvm-svn: 187300
2013-07-27 11:08:44 +00:00
Rafael Espindola e559af8205 Add not to commands that fail.
Polly devs: please check if these commands really should fail.

llvm-svn: 187263
2013-07-26 22:49:25 +00:00
Tobias Grosser 6bcb34b180 ScopDetect: Add some test cases for sequential loops
llvm-svn: 187024
2013-07-24 06:10:37 +00:00
Hongbin Zheng 63cc9467af Ensure a correct order between memory accesses.
Ensure that the scalar write access corresponds to the result of a load
instruction appears after the generic read access corresponds to the load
instruction.

llvm-svn: 186419
2013-07-16 15:20:29 +00:00
Hongbin Zheng 5a772dcd84 IndependentBlock: Add option to disable scalar to array rewriting.
llvm-svn: 186418
2013-07-16 15:19:33 +00:00
Tobias Grosser 6f0d6988a5 Dependences: Add a couple of basic test cases
llvm-svn: 186254
2013-07-13 18:31:46 +00:00
Tobias Grosser 229d681675 Dependences: Clarify difference between value and memory based dependences
We make the option a clear choice between the two analysis types and add
descriptions about the difference between the two.

llvm-svn: 186251
2013-07-13 17:37:55 +00:00
Sebastian Pop 784c012982 scop detection: remove an iteration over all uses
reenabled reverted patch after checking that it passes without regressions on
the nightly test-suite.  Added testcase from Tobi.

llvm-svn: 185720
2013-07-05 20:24:47 +00:00
Hongbin Zheng 8d3a888ca3 TempScop: (Partial) Implement the printDetail function.
llvm-svn: 185254
2013-06-29 07:00:14 +00:00
Tobias Grosser 4f96749351 ScopInfo: Clarify may-write and must-write accesses
llvm-svn: 184658
2013-06-23 05:21:18 +00:00
Tobias Grosser 3e030e178a Correctly convert APInt to gmp values
Previously this happend to work for integers up to i64, but we got it wrong
for larger numbers. Fix this and add test cases to verify this keeps working.

Reported by: Sven Verdoolaege <skimo at kotnet dot org>

llvm-svn: 183986
2013-06-14 16:23:38 +00:00
Sebastian Pop 9d63234ad1 ScopDetect: check region entering edges are valid.
When a region header is part of a loop, then all entering edges of this region
should not come from the loop but outside the region. Otherwise, the loop may be
only partially part of the region, which would cause troubles in handling
induction variables.

Currently, we can only model induction variables that are either fully part of
the scop (loop induction variable) or induction variables that are scop-
invariant (parameter). A loop that is only partially part of the
scop causes troubles, as there is no good way to handle the induction
variable in the independent blocks pass.

Contributed-by:    Star Tan <tanmx_star@yeah.net>
llvm-svn: 183800
2013-06-11 22:20:40 +00:00