Commit Graph

53 Commits

Author SHA1 Message Date
Benjamin Kramer 71a3512d60 DependenceAnalysis: Push #includes down into the implementation.
llvm-svn: 166688
2012-10-25 16:15:22 +00:00
Sebastian Pop e9623261ad fix warning
DependenceAnalysis.cpp:1164:32: warning: implicit truncation from 'int' to bitfield changes value from -5 to 3
      [-Wconstant-conversion]
    Result.DV[Level].Direction &= ~Dependence::DVEntry::GT;
                               ^  ~~~~~~~~~~~~~~~~~~~~~~~~

Patch from Preston Briggs <preston.briggs@gmail.com>.

llvm-svn: 165784
2012-10-12 02:04:32 +00:00
Sebastian Pop 59b61b9e2c dependence analysis
Patch from Preston Briggs <preston.briggs@gmail.com>.

This is an updated version of the dependence-analysis patch, including an MIV
test based on Banerjee's inequalities.

It's a fairly complete implementation of the paper

    Practical Dependence Testing
    Gina Goff, Ken Kennedy, and Chau-Wen Tseng
    PLDI 1991

It cannot yet propagate constraints between coupled RDIV subscripts (discussed
in Section 5.3.2 of the paper).

It's organized as a FunctionPass with a single entry point that supports testing
for dependence between two instructions in a function. If there's no dependence,
it returns null. If there's a dependence, it returns a pointer to a Dependence
which can be queried about details (what kind of dependence, is it loop
independent, direction and distance vector entries, etc). I haven't included
every imaginable feature, but there's a good selection that should be adequate
for supporting many loop transformations. Of course, it can be extended as
necessary.

Included in the patch file are many test cases, commented with C code showing
the loops and array references.

llvm-svn: 165708
2012-10-11 07:32:34 +00:00