diff options
Diffstat (limited to 'include/llvm/Transforms')
| -rw-r--r-- | include/llvm/Transforms/Utils/BypassSlowDivision.h | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/include/llvm/Transforms/Utils/BypassSlowDivision.h b/include/llvm/Transforms/Utils/BypassSlowDivision.h new file mode 100644 index 0000000000..4a9838aa75 --- /dev/null +++ b/include/llvm/Transforms/Utils/BypassSlowDivision.h @@ -0,0 +1,58 @@ +//===- 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 TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H +#define TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H + +#include "llvm/Function.h" + +/// This optimization identifies DIV instructions that can be +/// profitably bypassed and carried out with a shorter, faster divide. +bool bypassSlowDivision(llvm::Function &F, + llvm::Function::iterator &I, + const llvm::DenseMap<llvm::Type *, llvm::Type *> &BypassTypeMap); + +#endif +//===- 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 TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H +#define TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H + +#include "llvm/Function.h" + +/// This optimization identifies DIV instructions that can be +/// profitably bypassed and carried out with a shorter, faster divide. +bool bypassSlowDivision(llvm::Function &F, + llvm::Function::iterator &I, + const llvm::DenseMap<llvm::Type *, llvm::Type *> &BypassTypeMap); + +#endif |