From dd9344f3face8f1978a7f9f393c31b628144d1f6 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Fri, 28 May 2010 16:19:17 +0000 Subject: Move FindAvailableLoadedValue isSafeToLoadUnconditionally out of lib/Transforms/Utils and into lib/Analysis so that Analysis passes can use them. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104949 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/Loads.h | 51 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 include/llvm/Analysis/Loads.h (limited to 'include/llvm/Analysis/Loads.h') diff --git a/include/llvm/Analysis/Loads.h b/include/llvm/Analysis/Loads.h new file mode 100644 index 0000000000..1574262dd6 --- /dev/null +++ b/include/llvm/Analysis/Loads.h @@ -0,0 +1,51 @@ +//===- Loads.h - Local load analysis --------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file declares simple local analyses for load instructions. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ANALYSIS_LOADS_H +#define LLVM_ANALYSIS_LOADS_H + +#include "llvm/BasicBlock.h" + +namespace llvm { + +class AliasAnalysis; +class TargetData; + +/// isSafeToLoadUnconditionally - Return true if we know that executing a load +/// from this value cannot trap. If it is not obviously safe to load from the +/// specified pointer, we do a quick local scan of the basic block containing +/// ScanFrom, to determine if the address is already accessed. +bool isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom, + unsigned Align, const TargetData *TD = 0); + +/// FindAvailableLoadedValue - Scan the ScanBB block backwards (starting at +/// the instruction before ScanFrom) checking to see if we have the value at +/// the memory address *Ptr locally available within a small number of +/// instructions. If the value is available, return it. +/// +/// If not, return the iterator for the last validated instruction that the +/// value would be live through. If we scanned the entire block and didn't +/// find something that invalidates *Ptr or provides it, ScanFrom would be +/// left at begin() and this returns null. ScanFrom could also be left +/// +/// MaxInstsToScan specifies the maximum instructions to scan in the block. +/// If it is set to 0, it will scan the whole block. You can also optionally +/// specify an alias analysis implementation, which makes this more precise. +Value *FindAvailableLoadedValue(Value *Ptr, BasicBlock *ScanBB, + BasicBlock::iterator &ScanFrom, + unsigned MaxInstsToScan = 6, + AliasAnalysis *AA = 0); + +} + +#endif -- cgit v1.2.3