| //===- llvm/Transforms/Utils/BypassSlowDivision.h --------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains an optimization for div and rem on architectures that |
| // execute short instructions significantly faster than longer instructions. |
| // For example, on Intel Atom 32-bit divides are slow enough that during |
| // runtime it is profitable to check the value of the operands, and if they are |
| // positive and less than 256 use an unsigned 8-bit divide. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H |
| #define LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H |
| |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/IR/Function.h" |
| |
| namespace llvm { |
| |
| /// This optimization identifies DIV instructions in a BB that can be |
| /// profitably bypassed and carried out with a shorter, faster divide. |
| /// |
| /// This optimization may add basic blocks immediately after BB; for obvious |
| /// reasons, you shouldn't pass those blocks to bypassSlowDivision. |
| bool bypassSlowDivision( |
| BasicBlock *BB, const DenseMap<unsigned int, unsigned int> &BypassWidth); |
| |
| } // End llvm namespace |
| |
| #endif |
