/// \brief Return true for expressions that may incur non-trivial cost to
/// evaluate at runtime.
- bool isHighCostExpansion(const SCEV *Expr, Loop *L) {
+ ///
+ /// At is an optional parameter which specifies point in code where user is
+ /// going to expand this expression. Sometimes this knowledge can lead to a
+ /// more accurate cost estimation.
+ bool isHighCostExpansion(const SCEV *Expr, Loop *L,
+ const Instruction *At = nullptr) {
SmallPtrSet<const SCEV *, 8> Processed;
- return isHighCostExpansionHelper(Expr, L, Processed);
+ return isHighCostExpansionHelper(Expr, L, At, Processed);
}
/// \brief This method returns the canonical induction variable of the
/// block.
Value *expandCodeFor(const SCEV *SH, Type *Ty, Instruction *I);
+ /// \brief Generates a code sequence that evaluates this predicate.
+ /// The inserted instructions will be at position \p Loc.
+ /// The result will be of type i1 and will have a value of 0 when the
+ /// predicate is false and 1 otherwise.
+ Value *expandCodeForPredicate(const SCEVPredicate *Pred, Instruction *Loc);
+
+ /// \brief A specialized variant of expandCodeForPredicate, handling the
+ /// case when we are expanding code for a SCEVEqualPredicate.
+ Value *expandEqualPredicate(const SCEVEqualPredicate *Pred,
+ Instruction *Loc);
+
+ /// \brief A specialized variant of expandCodeForPredicate, handling the
+ /// case when we are expanding code for a SCEVUnionPredicate.
+ Value *expandUnionPredicate(const SCEVUnionPredicate *Pred,
+ Instruction *Loc);
+
/// \brief Set the current IV increment loop and position.
void setIVIncInsertPos(const Loop *L, Instruction *Pos) {
assert(!CanonicalMode &&
void setChainedPhi(PHINode *PN) { ChainedPhis.insert(PN); }
+ /// \brief Try to find LLVM IR value for S available at the point At.
+ ///
+ /// L is a hint which tells in which loop to look for the suitable value.
+ /// On success return value which is equivalent to the expanded S at point
+ /// At. Return nullptr if value was not found.
+ ///
+ /// Note that this function does not perform an exhaustive search. I.e if it
+ /// didn't find any value it does not mean that there is no such value.
+ Value *findExistingExpansion(const SCEV *S, const Instruction *At, Loop *L);
+
private:
LLVMContext &getContext() const { return SE.getContext(); }
/// \brief Recursive helper function for isHighCostExpansion.
bool isHighCostExpansionHelper(const SCEV *S, Loop *L,
+ const Instruction *At,
SmallPtrSetImpl<const SCEV *> &Processed);
/// \brief Insert the specified binary operator, doing a small amount