Commit 6e530a3d authored by Jeroen Dobbelaere's avatar Jeroen Dobbelaere
Browse files

[Verifier] enable and limit llvm.experimental.noalias.scope.decl dominance checking 

Checking the llvm.experimental.noalias.scope.decl dominance can be worstcase O(N^2).
Limit the dominance check to N=32.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D95335
parent 7e506b30

llvm/lib/IR/Verifier.cpp

+12 −13
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ 
using namespace llvm;



static cl::opt<bool> VerifyNoAliasScopeDomination(

    "verify-noalias-scope-decl-dom", cl::Hidden, cl::init(false),

    "verify-noalias-scope-decl-dom", cl::Hidden, cl::init(true),

    cl::desc("Ensure that llvm.experimental.noalias.scope.decl for identical "

             "scopes are not dominating"));
@@ -5587,18 +5587,17 @@ void Verifier::verifyNoAliasScopeDecl() { 
    } while (ItNext != NoAliasScopeDecls.end() &&

             GetScope(*ItNext) == CurScope);



    // [ItCurrent, ItNext[ represents the declarations for the same scope.

    // Ensure they are not dominating each other

    for (auto *I : llvm::make_range(ItCurrent, ItNext)) {

      for (auto *J : llvm::make_range(ItCurrent, ItNext)) {

        if (I != J) {

    // [ItCurrent, ItNext) represents the declarations for the same scope.

    // Ensure they are not dominating each other.. but only if it is not too

    // expensive.

    if (ItNext - ItCurrent < 32)

      for (auto *I : llvm::make_range(ItCurrent, ItNext))

        for (auto *J : llvm::make_range(ItCurrent, ItNext))

          if (I != J)

            Assert(!DT.dominates(I, J),

                   "llvm.experimental.noalias.scope.decl dominates another one "

                   "with the same scope",

                   I);

        }

      }

    }

    ItCurrent = ItNext;

  }

}