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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172025 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
1.3 KiB
C++
35 lines
1.3 KiB
C++
//===- llvm/Transforms/Utils/BypassSlowDivision.h --------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains an optimization for div and rem on architectures that
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// execute short instructions significantly faster than longer instructions.
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// For example, on Intel Atom 32-bit divides are slow enough that during
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// runtime it is profitable to check the value of the operands, and if they are
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// positive and less than 256 use an unsigned 8-bit divide.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H
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#define LLVM_TRANSFORMS_UTILS_BYPASSSLOWDIVISION_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/IR/Function.h"
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namespace llvm {
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/// This optimization identifies DIV instructions that can be
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/// profitably bypassed and carried out with a shorter, faster divide.
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bool bypassSlowDivision(Function &F,
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Function::iterator &I,
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const DenseMap<unsigned int, unsigned int> &BypassWidth);
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} // End llvm namespace
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#endif
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