[llvm-bugs] [Bug 32532] New: Too many scalar dependencies in loops with load-hoisted bounds

[via llvm-bugs]

http://bugs.llvm.org/show_bug.cgi?id=32532

            Bug ID: 32532
           Summary: Too many scalar dependencies in loops with
                    load-hoisted bounds
           Product: Polly
           Version: unspecified
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Optimizer
          Assignee: polly-dev at googlegroups.com
          Reporter: llvm at meinersbur.de
                CC: llvm-bugs at lists.llvm.org

Created attachment 18227
  --> http://bugs.llvm.org/attachment.cgi?id=18227&action=edit
reduction_looprotate_loadhoist.ll

The attached file reduction_looprotate_loadhoist.ll has too many scalar
dependencies. In particular, it passes the loop induction variable %i as scalar
accesses even though the loop induction variable will be generated by
IslNodeBuilder and the old value is never referenced.

$ opt reduction_looprotate_loadhoist.ll -polly-process-unprofitable
-polly-invariant-load-hoisting -polly-scops -analyze

    Statements {
        Stmt_reduction_preheader
            Domain :=
                [Start] -> { Stmt_reduction_preheader[i0] : 0 <= i0 <= 1 };
            Schedule :=
                [Start] -> { Stmt_reduction_preheader[i0] -> [i0, 0, 0, 0] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_preheader[i0] -> MemRef_i__phi[] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_preheader[i0] -> MemRef_phi__phi[]
};
        Stmt_reduction_for
            Domain :=
                [Start] -> { Stmt_reduction_for[i0, i1] : 0 <= i0 <= 1 and 0 <
i1 <= 3 - Start; Stmt_reduction_for[i0, 0] : 0 <= i0 <= 1 };
            Schedule :=
                [Start] -> { Stmt_reduction_for[i0, i1] -> [i0, 1, i1, 0] : 0 <
i1 <= 3 - Start; Stmt_reduction_for[i0, 0] -> [i0, 1, 0, 0] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_for[i0, i1] -> MemRef_i__phi[] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_for[i0, i1] -> MemRef_phi__phi[] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_for[i0, i1] -> MemRef_phi[] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_for[i0, i1] -> MemRef_i[] };
        Stmt_body
            Domain :=
                [Start] -> { Stmt_body[i0, i1] : 0 <= i0 <= 1 and 0 < i1 <= 3 -
Start; Stmt_body[i0, 0] : 0 <= i0 <= 1 };
            Schedule :=
                [Start] -> { Stmt_body[i0, i1] -> [i0, 1, i1, 1] : 0 < i1 <= 3
- Start; Stmt_body[i0, 0] -> [i0, 1, 0, 1] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_body[i0, i1] -> MemRef_mul[] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_body[i0, i1] -> MemRef_phi[] };
        Stmt_reduction_inc
            Domain :=
                [Start] -> { Stmt_reduction_inc[i0, i1] : 0 <= i0 <= 1 and 0 <
i1 <= 3 - Start; Stmt_reduction_inc[i0, 0] : 0 <= i0 <= 1 };
            Schedule :=
                [Start] -> { Stmt_reduction_inc[i0, i1] -> [i0, 1, i1, 2] : 0 <
i1 <= 3 - Start; Stmt_reduction_inc[i0, 0] -> [i0, 1, 0, 2] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_inc[i0, i1] -> MemRef_i__phi[] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_inc[i0, i1] -> MemRef_mul[] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_inc[i0, i1] -> MemRef_phi__phi[] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_inc[i0, i1] -> MemRef_i[] };
        Stmt_reduction_exit
            Domain :=
                [Start] -> { Stmt_reduction_exit[i0] : 0 <= i0 <= 1 };
            Schedule :=
                [Start] -> { Stmt_reduction_exit[i0] -> [i0, 2, 0, 0] };
            MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 0]
                [Start] -> { Stmt_reduction_exit[i0] -> MemRef_A[i0] };
            ReadAccess :=       [Reduction Type: NONE] [Scalar: 1]
                [Start] -> { Stmt_reduction_exit[i0] -> MemRef_mul[] };
    }

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20170405/19e71886/attachment-0001.html>