[polly][PATCH] Derive run-time conditions for delinearization

[Tobias Grosser]

Hi,

I would like to ask for feedback on the following patch:

[polly][PATCH] Derive run-time conditions for delinearization

As our delinearization works optimistically, we need in some cases 
run-time checks that verify our optimistic assumptions. A simple example 
is the following code:

void foo(long n, long m, long o, double A[n][m][o]) {

   for (long i = 0; i < 100; i++)
     for (long j = 0; j < 150; j++)
       for (long k = 0; k < 200; k++)
         A[i][j][k] = 1.0;
}

After clang linearized the access to A and we delinearized it again to
A[i][j][k] we need to ensure that we do not access the delinearized 
array out of bounds (this information is not available in LLVM-IR). 
Hence, we need to verify the following constraints at run-time:

CHECK:   Assumed Context:
CHECK:   [o, m] -> {  : m >= 150 and o >= 200 }
---
  include/polly/ScopInfo.h                           | 19 ++++++
  lib/Analysis/ScopInfo.cpp                          | 78 
++++++++++++++++++++++
  lib/CodeGen/IslCodeGeneration.cpp                  |  5 +-
  ...tidim_2d_parametric_array_static_loop_bounds.ll | 44 ++++++++++++
  test/ScopInfo/multidim_2d-diagonal-matrix.ll       |  4 ++
  .../ScopInfo/multidim_2d_outer_larger_than_zero.ll | 54 +++++++++++++++
  ...tidim_2d_parametric_array_static_loop_bounds.ll | 50 ++++++++++++++
  ...tidim_3d_parametric_array_static_loop_bounds.ll | 66 ++++++++++++++++++
  .../multidim_ivs_and_integer_offsets_3d.ll         |  3 +
  .../multidim_ivs_and_parameteric_offsets_3d.ll     | 11 +++
  test/ScopInfo/multidim_nested_start_integer.ll     |  2 +
  .../multidim_nested_start_share_parameter.ll       |  2 +
  test/ScopInfo/multidim_only_ivs_2d.ll              |  2 +
  test/ScopInfo/multidim_only_ivs_3d.ll              |  2 +
  test/ScopInfo/multidim_only_ivs_3d_cast.ll         | 16 +++--
  test/ScopInfo/multidim_only_ivs_3d_reverse.ll      | 46 +++++++------
  test/ScopInfo/simple_loop_1.ll                     |  3 +
  17 files changed, 380 insertions(+), 27 deletions(-)
  create mode 100644 
test/Isl/CodeGen/multidim_2d_parametric_array_static_loop_bounds.ll
  create mode 100644 test/ScopInfo/multidim_2d_outer_larger_than_zero.ll
  create mode 100644 
test/ScopInfo/multidim_2d_parametric_array_static_loop_bounds.ll
  create mode 100644 
test/ScopInfo/multidim_3d_parametric_array_static_loop_bounds.ll

Thanks,
Tobias


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