Use parameter constraints provided via llvm.assume

  If an llvm.assume dominates the SCoP entry block and the assumed condition
  can be expressed as an affine inequality we will now add it to the context.

Differential Revision: http://reviews.llvm.org/D14413

llvm-svn: 252851

1 files changed, 38 insertions, 0 deletions

diff --git a/polly/lib/Support/SCEVValidator.cpp b/polly/lib/Support/SCEVValidator.cpp
index 9b3ce1860d5..e22d3df162e 100644
--- a/polly/lib/Support/SCEVValidator.cpp
+++ b/polly/lib/Support/SCEVValidator.cpp
@@ -587,6 +587,44 @@ bool isAffineExpr(const Region *R, const SCEV *Expr, ScalarEvolution &SE,
   return Result.isValid();
 }
 
+static bool isAffineParamExpr(Value *V, const Region *R, ScalarEvolution &SE,
+                              std::vector<const SCEV *> &Params) {
+  auto *E = SE.getSCEV(V);
+  if (isa<SCEVCouldNotCompute>(E))
+    return false;
+
+  SCEVValidator Validator(R, SE, nullptr, nullptr);
+  ValidatorResult Result = Validator.visit(E);
+  if (!Result.isConstant())
+    return false;
+
+  auto ResultParams = Result.getParameters();
+  Params.insert(Params.end(), ResultParams.begin(), ResultParams.end());
+
+  return true;
+}
+
+bool isAffineParamConstraint(Value *V, const Region *R, ScalarEvolution &SE,
+                             std::vector<const SCEV *> &Params, bool OrExpr) {
+  if (auto *ICmp = dyn_cast<ICmpInst>(V)) {
+    return isAffineParamConstraint(ICmp->getOperand(0), R, SE, Params, true) &&
+           isAffineParamConstraint(ICmp->getOperand(1), R, SE, Params, true);
+  } else if (auto *BinOp = dyn_cast<BinaryOperator>(V)) {
+    auto Opcode = BinOp->getOpcode();
+    if (Opcode == Instruction::And || Opcode == Instruction::Or)
+      return isAffineParamConstraint(BinOp->getOperand(0), R, SE, Params,
+                                     false) &&
+             isAffineParamConstraint(BinOp->getOperand(1), R, SE, Params,
+                                     false);
+    /* Fall through */
+  }
+
+  if (!OrExpr)
+    return false;
+
+  return isAffineParamExpr(V, R, SE, Params);
+}
+
 std::vector<const SCEV *> getParamsInAffineExpr(const Region *R,
                                                 const SCEV *Expr,
                                                 ScalarEvolution &SE,