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a559a2317c
Take two disjoint Loops L1 and L2. LoopSimplify fails to simplify some loops (e.g. when indirect branches are involved). In such situations, it can happen that an exit for L1 is the header of L2. Thus, when we create PHIs in one of such exits we are also inserting PHIs in L2 header. This could break LCSSA form for L2 because these inserted PHIs can also have uses in L2 exits, which are never handled in the current implementation. Provide a fix for this corner case and test that we don't assert/crash on that. Differential Revision: http://reviews.llvm.org/D6624 rdar://problem/19166231 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224740 91177308-0d34-0410-b5e6-96231b3b80d8
69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
//===- llvm/Transforms/Utils/LoopUtils.h - Loop utilities -*- 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 defines some loop transformation utilities.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_LOOPUTILS_H
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#define LLVM_TRANSFORMS_UTILS_LOOPUTILS_H
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namespace llvm {
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class AliasAnalysis;
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class AssumptionTracker;
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class BasicBlock;
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class DataLayout;
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class DominatorTree;
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class Loop;
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class LoopInfo;
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class Pass;
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class ScalarEvolution;
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BasicBlock *InsertPreheaderForLoop(Loop *L, Pass *P);
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/// \brief Simplify each loop in a loop nest recursively.
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///
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/// This takes a potentially un-simplified loop L (and its children) and turns
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/// it into a simplified loop nest with preheaders and single backedges. It
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/// will optionally update \c AliasAnalysis and \c ScalarEvolution analyses if
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/// passed into it.
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bool simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
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AliasAnalysis *AA = nullptr, ScalarEvolution *SE = nullptr,
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const DataLayout *DL = nullptr,
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AssumptionTracker *AT = nullptr);
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/// \brief Put loop into LCSSA form.
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///
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/// Looks at all instructions in the loop which have uses outside of the
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/// current loop. For each, an LCSSA PHI node is inserted and the uses outside
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/// the loop are rewritten to use this node.
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///
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/// LoopInfo and DominatorTree are required and preserved.
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///
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/// If ScalarEvolution is passed in, it will be preserved.
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///
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/// Returns true if any modifications are made to the loop.
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bool formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI,
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ScalarEvolution *SE = nullptr);
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/// \brief Put a loop nest into LCSSA form.
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///
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/// This recursively forms LCSSA for a loop nest.
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///
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/// LoopInfo and DominatorTree are required and preserved.
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///
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/// If ScalarEvolution is passed in, it will be preserved.
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///
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/// Returns true if any modifications are made to the loop.
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bool formLCSSARecursively(Loop &L, DominatorTree &DT, LoopInfo *LI,
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ScalarEvolution *SE = nullptr);
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}
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#endif
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