[llvm] r187283 - Reimplement isPotentiallyReachable to make nocapture deduction much stronger.
Nick Lewycky
nicholas at mxc.ca
Fri Jul 26 18:24:00 PDT 2013
Author: nicholas
Date: Fri Jul 26 20:24:00 2013
New Revision: 187283
URL: http://llvm.org/viewvc/llvm-project?rev=187283&view=rev
Log:
Reimplement isPotentiallyReachable to make nocapture deduction much stronger.
Adds unit tests for it too.
Split BasicBlockUtils into an analysis-half and a transforms-half, and put the
analysis bits into a new Analysis/CFG.{h,cpp}. Promote isPotentiallyReachable
into llvm::isPotentiallyReachable and move it into Analysis/CFG.
Added:
llvm/trunk/include/llvm/Analysis/CFG.h
llvm/trunk/lib/Analysis/CFG.cpp
llvm/trunk/unittests/Analysis/CFGTest.cpp
Modified:
llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h
llvm/trunk/lib/Analysis/AliasAnalysis.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
llvm/trunk/lib/Transforms/Scalar/GVN.cpp
llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
llvm/trunk/lib/Transforms/Utils/BreakCriticalEdges.cpp
llvm/trunk/lib/Transforms/Utils/DemoteRegToStack.cpp
llvm/trunk/unittests/Analysis/CMakeLists.txt
llvm/trunk/unittests/Analysis/Makefile
Added: llvm/trunk/include/llvm/Analysis/CFG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/CFG.h?rev=187283&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Analysis/CFG.h (added)
+++ llvm/trunk/include/llvm/Analysis/CFG.h Fri Jul 26 20:24:00 2013
@@ -0,0 +1,69 @@
+//===-- Analysis/CFG.h - BasicBlock Analyses --------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This family of functions performs analyses on basic blocks, and instructions
+// contained within basic blocks.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_CFG_H
+#define LLVM_ANALYSIS_CFG_H
+
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/Support/CFG.h"
+
+namespace llvm {
+
+class BasicBlock;
+class DominatorTree;
+class Function;
+class Instruction;
+class LoopInfo;
+class TerminatorInst;
+
+/// Analyze the specified function to find all of the loop backedges in the
+/// function and return them. This is a relatively cheap (compared to
+/// computing dominators and loop info) analysis.
+///
+/// The output is added to Result, as pairs of <from,to> edge info.
+void FindFunctionBackedges(
+ const Function &F,
+ SmallVectorImpl<std::pair<const BasicBlock *, const BasicBlock *> > &
+ Result);
+
+/// Search for the specified successor of basic block BB and return its position
+/// in the terminator instruction's list of successors. It is an error to call
+/// this with a block that is not a successor.
+unsigned GetSuccessorNumber(BasicBlock *BB, BasicBlock *Succ);
+
+/// Return true if the specified edge is a critical edge. Critical edges are
+/// edges from a block with multiple successors to a block with multiple
+/// predecessors.
+///
+bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
+ bool AllowIdenticalEdges = false);
+
+/// Determine whether there is a path from From to To within a single function.
+/// Returns false only if we can prove that once 'From' has been executed then
+/// 'To' can not be executed. Conservatively returns true.
+///
+/// This function is linear with respect to the number of blocks in the CFG,
+/// walking down successors from From to reach To, with a fixed threshold.
+/// Using DT or LI allows us to answer more quickly. LI reduces the cost of
+/// an entire loop of any number of blocsk to be the same as the cost of a
+/// single block. DT reduces the cost by allowing the search to terminate when
+/// we find a block that dominates the block containing 'To'. DT is most useful
+/// on branchy code but not loops, and LI is most useful on code with loops but
+/// does not help on branchy code outside loops.
+bool isPotentiallyReachable(const Instruction *From, const Instruction *To,
+ DominatorTree *DT = 0, LoopInfo *LI = 0);
+
+} // End llvm namespace
+
+#endif
Modified: llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h Fri Jul 26 20:24:00 2013
@@ -70,28 +70,6 @@ void ReplaceInstWithInst(BasicBlock::Ins
//
void ReplaceInstWithInst(Instruction *From, Instruction *To);
-/// FindFunctionBackedges - Analyze the specified function to find all of the
-/// loop backedges in the function and return them. This is a relatively cheap
-/// (compared to computing dominators and loop info) analysis.
-///
-/// The output is added to Result, as pairs of <from,to> edge info.
-void FindFunctionBackedges(const Function &F,
- SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result);
-
-
-/// GetSuccessorNumber - Search for the specified successor of basic block BB
-/// and return its position in the terminator instruction's list of
-/// successors. It is an error to call this with a block that is not a
-/// successor.
-unsigned GetSuccessorNumber(BasicBlock *BB, BasicBlock *Succ);
-
-/// isCriticalEdge - Return true if the specified edge is a critical edge.
-/// Critical edges are edges from a block with multiple successors to a block
-/// with multiple predecessors.
-///
-bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
- bool AllowIdenticalEdges = false);
-
/// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
/// split the critical edge. This will update DominatorTree and
/// DominatorFrontier information if it is available, thus calling this pass
Modified: llvm/trunk/lib/Analysis/AliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasAnalysis.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasAnalysis.cpp Fri Jul 26 20:24:00 2013
@@ -26,6 +26,7 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
@@ -361,26 +362,6 @@ AliasAnalysis::getModRefInfo(const Atomi
}
namespace {
- /// Determine whether there is a path from From to To within a single
- /// function. Returns false only if we can prove that once 'From' has been
- /// executed then 'To' can not be executed. Conservatively returns true.
- static bool isPotentiallyReachable(const BasicBlock *From,
- const BasicBlock *To) {
- const unsigned MaxCheck = 5;
- const BasicBlock *Current = From;
- for (unsigned I = 0; I < MaxCheck; I++) {
- unsigned NumSuccs = Current->getTerminator()->getNumSuccessors();
- if (NumSuccs > 1)
- return true;
- if (NumSuccs == 0)
- return false;
- Current = Current->getTerminator()->getSuccessor(0);
- if (Current == To)
- return true;
- }
- return true;
- }
-
/// Only find pointer captures which happen before the given instruction. Uses
/// the dominator tree to determine whether one instruction is before another.
/// Only support the case where the Value is defined in the same basic block
@@ -402,7 +383,7 @@ namespace {
// there is no need to explore the use if BeforeHere dominates use.
// Check whether there is a path from I to BeforeHere.
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
- !isPotentiallyReachable(BB, BeforeHere->getParent()))
+ !isPotentiallyReachable(I, BeforeHere, DT))
return false;
return true;
}
@@ -414,7 +395,7 @@ namespace {
if (BeforeHere != I && !DT->isReachableFromEntry(BB))
return false;
if (BeforeHere != I && DT->dominates(BeforeHere, I) &&
- !isPotentiallyReachable(BB, BeforeHere->getParent()))
+ !isPotentiallyReachable(I, BeforeHere, DT))
return false;
Captured = true;
return true;
Added: llvm/trunk/lib/Analysis/CFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/CFG.cpp?rev=187283&view=auto
==============================================================================
--- llvm/trunk/lib/Analysis/CFG.cpp (added)
+++ llvm/trunk/lib/Analysis/CFG.cpp Fri Jul 26 20:24:00 2013
@@ -0,0 +1,227 @@
+//===-- CFG.cpp - BasicBlock analysis --------------------------------------==//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This family of functions performs analyses on basic blocks, and instructions
+// contained within basic blocks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CFG.h"
+
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+using namespace llvm;
+
+/// FindFunctionBackedges - Analyze the specified function to find all of the
+/// loop backedges in the function and return them. This is a relatively cheap
+/// (compared to computing dominators and loop info) analysis.
+///
+/// The output is added to Result, as pairs of <from,to> edge info.
+void llvm::FindFunctionBackedges(const Function &F,
+ SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result) {
+ const BasicBlock *BB = &F.getEntryBlock();
+ if (succ_begin(BB) == succ_end(BB))
+ return;
+
+ SmallPtrSet<const BasicBlock*, 8> Visited;
+ SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;
+ SmallPtrSet<const BasicBlock*, 8> InStack;
+
+ Visited.insert(BB);
+ VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+ InStack.insert(BB);
+ do {
+ std::pair<const BasicBlock*, succ_const_iterator> &Top = VisitStack.back();
+ const BasicBlock *ParentBB = Top.first;
+ succ_const_iterator &I = Top.second;
+
+ bool FoundNew = false;
+ while (I != succ_end(ParentBB)) {
+ BB = *I++;
+ if (Visited.insert(BB)) {
+ FoundNew = true;
+ break;
+ }
+ // Successor is in VisitStack, it's a back edge.
+ if (InStack.count(BB))
+ Result.push_back(std::make_pair(ParentBB, BB));
+ }
+
+ if (FoundNew) {
+ // Go down one level if there is a unvisited successor.
+ InStack.insert(BB);
+ VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+ } else {
+ // Go up one level.
+ InStack.erase(VisitStack.pop_back_val().first);
+ }
+ } while (!VisitStack.empty());
+}
+
+/// GetSuccessorNumber - Search for the specified successor of basic block BB
+/// and return its position in the terminator instruction's list of
+/// successors. It is an error to call this with a block that is not a
+/// successor.
+unsigned llvm::GetSuccessorNumber(BasicBlock *BB, BasicBlock *Succ) {
+ TerminatorInst *Term = BB->getTerminator();
+#ifndef NDEBUG
+ unsigned e = Term->getNumSuccessors();
+#endif
+ for (unsigned i = 0; ; ++i) {
+ assert(i != e && "Didn't find edge?");
+ if (Term->getSuccessor(i) == Succ)
+ return i;
+ }
+}
+
+/// isCriticalEdge - Return true if the specified edge is a critical edge.
+/// Critical edges are edges from a block with multiple successors to a block
+/// with multiple predecessors.
+bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
+ bool AllowIdenticalEdges) {
+ assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
+ if (TI->getNumSuccessors() == 1) return false;
+
+ const BasicBlock *Dest = TI->getSuccessor(SuccNum);
+ const_pred_iterator I = pred_begin(Dest), E = pred_end(Dest);
+
+ // If there is more than one predecessor, this is a critical edge...
+ assert(I != E && "No preds, but we have an edge to the block?");
+ const BasicBlock *FirstPred = *I;
+ ++I; // Skip one edge due to the incoming arc from TI.
+ if (!AllowIdenticalEdges)
+ return I != E;
+
+ // If AllowIdenticalEdges is true, then we allow this edge to be considered
+ // non-critical iff all preds come from TI's block.
+ while (I != E) {
+ const BasicBlock *P = *I;
+ if (P != FirstPred)
+ return true;
+ // Note: leave this as is until no one ever compiles with either gcc 4.0.1
+ // or Xcode 2. This seems to work around the pred_iterator assert in PR 2207
+ E = pred_end(P);
+ ++I;
+ }
+ return false;
+}
+
+// LoopInfo contains a mapping from basic block to the innermost loop. Find
+// the outermost loop in the loop nest that contains BB.
+static const Loop *getOutermostLoop(LoopInfo *LI, const BasicBlock *BB) {
+ const Loop *L = LI->getLoopFor(BB);
+ if (L) {
+ while (const Loop *Parent = L->getParentLoop())
+ L = Parent;
+ }
+ return L;
+}
+
+// True if there is a loop which contains both BB1 and BB2.
+static bool loopContainsBoth(LoopInfo *LI,
+ const BasicBlock *BB1, const BasicBlock *BB2) {
+ const Loop *L1 = getOutermostLoop(LI, BB1);
+ const Loop *L2 = getOutermostLoop(LI, BB2);
+ return L1 != NULL && L1 == L2;
+}
+
+static bool isPotentiallyReachableSameBlock(const Instruction *A,
+ const Instruction *B,
+ LoopInfo *LI) {
+ // The same block case is special because it's the only time we're looking
+ // within a single block to see which comes first. Once we start looking at
+ // multiple blocks, the first instruction of the block is reachable, so we
+ // only need to determine reachability between whole blocks.
+
+ const BasicBlock *BB = A->getParent();
+ // If the block is in a loop then we can reach any instruction in the block
+ // from any other instruction in the block by going around the backedge.
+ // Check whether we're in a loop (or aren't sure).
+
+ // Can't be in a loop if it's the entry block -- the entry block may not
+ // have predecessors.
+ bool HasLoop = BB != &BB->getParent()->getEntryBlock();
+
+ // Can't be in a loop if LoopInfo doesn't know about it.
+ if (LI && HasLoop) {
+ HasLoop = LI->getLoopFor(BB) != 0;
+ }
+ if (HasLoop)
+ return true;
+
+ // Linear scan, start at 'A', see whether we hit 'B' or the end first.
+ for (BasicBlock::const_iterator I = A, E = BB->end(); I != E; ++I) {
+ if (&*I == B)
+ return true;
+ }
+ return false;
+}
+
+bool llvm::isPotentiallyReachable(const Instruction *A, const Instruction *B,
+ DominatorTree *DT, LoopInfo *LI) {
+ assert(A->getParent()->getParent() == B->getParent()->getParent() &&
+ "This analysis is function-local!");
+
+ const BasicBlock *StopBB = B->getParent();
+
+ if (A->getParent() == B->getParent())
+ return isPotentiallyReachableSameBlock(A, B, LI);
+
+ if (A->getParent() == &A->getParent()->getParent()->getEntryBlock())
+ return true;
+ if (B->getParent() == &A->getParent()->getParent()->getEntryBlock())
+ return false;
+
+ // When the stop block is unreachable, it's dominated from everywhere,
+ // regardless of whether there's a path between the two blocks.
+ if (DT && !DT->isReachableFromEntry(StopBB))
+ DT = 0;
+
+ // Limit the number of blocks we visit. The goal is to avoid run-away compile
+ // times on large CFGs without hampering sensible code. Arbitrarily chosen.
+ unsigned Limit = 32;
+
+ SmallSet<const BasicBlock*, 64> Visited;
+ SmallVector<BasicBlock*, 32> Worklist;
+ Worklist.push_back(const_cast<BasicBlock*>(A->getParent()));
+
+ do {
+ BasicBlock *BB = Worklist.pop_back_val();
+ if (!Visited.insert(BB))
+ continue;
+ if (BB == StopBB)
+ return true;
+ if (DT && DT->dominates(BB, StopBB))
+ return true;
+ if (LI && loopContainsBoth(LI, BB, StopBB))
+ return true;
+
+ if (!--Limit) {
+ // We haven't been able to prove it one way or the other. Conservatively
+ // answer true -- that there is potentially a path.
+ return true;
+ }
+
+ if (const Loop *Outer = LI ? getOutermostLoop(LI, BB) : 0) {
+ // All blocks in a single loop are reachable from all other blocks. From
+ // any of these blocks, we can skip directly to the exits of the loop,
+ // ignoring any other blocks inside the loop body.
+ Outer->getExitBlocks(Worklist);
+ } else {
+ for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
+ Worklist.push_back(*I);
+ }
+ } while (!Worklist.empty());
+
+ // We have exhaustived all possible paths and are certain that 'To' can not
+ // be reached from 'From'.
+ return false;
+}
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Fri Jul 26 20:24:00 2013
@@ -19,6 +19,7 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Fri Jul 26 20:24:00 2013
@@ -23,6 +23,7 @@
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
Modified: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp Fri Jul 26 20:24:00 2013
@@ -19,6 +19,7 @@
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LazyValueInfo.h"
@@ -1614,5 +1615,3 @@ bool JumpThreading::DuplicateCondBranchO
++NumDupes;
return true;
}
-
-
Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Fri Jul 26 20:24:00 2013
@@ -14,6 +14,7 @@
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
@@ -235,22 +236,6 @@ void llvm::ReplaceInstWithInst(Instructi
ReplaceInstWithInst(From->getParent()->getInstList(), BI, To);
}
-/// GetSuccessorNumber - Search for the specified successor of basic block BB
-/// and return its position in the terminator instruction's list of
-/// successors. It is an error to call this with a block that is not a
-/// successor.
-unsigned llvm::GetSuccessorNumber(BasicBlock *BB, BasicBlock *Succ) {
- TerminatorInst *Term = BB->getTerminator();
-#ifndef NDEBUG
- unsigned e = Term->getNumSuccessors();
-#endif
- for (unsigned i = 0; ; ++i) {
- assert(i != e && "Didn't find edge?");
- if (Term->getSuccessor(i) == Succ)
- return i;
- }
-}
-
/// SplitEdge - Split the edge connecting specified block. Pass P must
/// not be NULL.
BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
@@ -598,52 +583,6 @@ void llvm::SplitLandingPadPredecessors(B
}
}
-/// FindFunctionBackedges - Analyze the specified function to find all of the
-/// loop backedges in the function and return them. This is a relatively cheap
-/// (compared to computing dominators and loop info) analysis.
-///
-/// The output is added to Result, as pairs of <from,to> edge info.
-void llvm::FindFunctionBackedges(const Function &F,
- SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result) {
- const BasicBlock *BB = &F.getEntryBlock();
- if (succ_begin(BB) == succ_end(BB))
- return;
-
- SmallPtrSet<const BasicBlock*, 8> Visited;
- SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;
- SmallPtrSet<const BasicBlock*, 8> InStack;
-
- Visited.insert(BB);
- VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
- InStack.insert(BB);
- do {
- std::pair<const BasicBlock*, succ_const_iterator> &Top = VisitStack.back();
- const BasicBlock *ParentBB = Top.first;
- succ_const_iterator &I = Top.second;
-
- bool FoundNew = false;
- while (I != succ_end(ParentBB)) {
- BB = *I++;
- if (Visited.insert(BB)) {
- FoundNew = true;
- break;
- }
- // Successor is in VisitStack, it's a back edge.
- if (InStack.count(BB))
- Result.push_back(std::make_pair(ParentBB, BB));
- }
-
- if (FoundNew) {
- // Go down one level if there is a unvisited successor.
- InStack.insert(BB);
- VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
- } else {
- // Go up one level.
- InStack.erase(VisitStack.pop_back_val().first);
- }
- } while (!VisitStack.empty());
-}
-
/// FoldReturnIntoUncondBranch - This method duplicates the specified return
/// instruction into a predecessor which ends in an unconditional branch. If
/// the return instruction returns a value defined by a PHI, propagate the
Modified: llvm/trunk/lib/Transforms/Utils/BreakCriticalEdges.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BreakCriticalEdges.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BreakCriticalEdges.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BreakCriticalEdges.cpp Fri Jul 26 20:24:00 2013
@@ -19,6 +19,7 @@
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ProfileInfo.h"
@@ -84,39 +85,6 @@ bool BreakCriticalEdges::runOnFunction(F
// Implementation of the external critical edge manipulation functions
//===----------------------------------------------------------------------===//
-// isCriticalEdge - Return true if the specified edge is a critical edge.
-// Critical edges are edges from a block with multiple successors to a block
-// with multiple predecessors.
-//
-bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
- bool AllowIdenticalEdges) {
- assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
- if (TI->getNumSuccessors() == 1) return false;
-
- const BasicBlock *Dest = TI->getSuccessor(SuccNum);
- const_pred_iterator I = pred_begin(Dest), E = pred_end(Dest);
-
- // If there is more than one predecessor, this is a critical edge...
- assert(I != E && "No preds, but we have an edge to the block?");
- const BasicBlock *FirstPred = *I;
- ++I; // Skip one edge due to the incoming arc from TI.
- if (!AllowIdenticalEdges)
- return I != E;
-
- // If AllowIdenticalEdges is true, then we allow this edge to be considered
- // non-critical iff all preds come from TI's block.
- while (I != E) {
- const BasicBlock *P = *I;
- if (P != FirstPred)
- return true;
- // Note: leave this as is until no one ever compiles with either gcc 4.0.1
- // or Xcode 2. This seems to work around the pred_iterator assert in PR 2207
- E = pred_end(P);
- ++I;
- }
- return false;
-}
-
/// createPHIsForSplitLoopExit - When a loop exit edge is split, LCSSA form
/// may require new PHIs in the new exit block. This function inserts the
/// new PHIs, as needed. Preds is a list of preds inside the loop, SplitBB
Modified: llvm/trunk/lib/Transforms/Utils/DemoteRegToStack.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/DemoteRegToStack.cpp?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/DemoteRegToStack.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/DemoteRegToStack.cpp Fri Jul 26 20:24:00 2013
@@ -10,6 +10,7 @@
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Type.h"
Added: llvm/trunk/unittests/Analysis/CFGTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Analysis/CFGTest.cpp?rev=187283&view=auto
==============================================================================
--- llvm/trunk/unittests/Analysis/CFGTest.cpp (added)
+++ llvm/trunk/unittests/Analysis/CFGTest.cpp Fri Jul 26 20:24:00 2013
@@ -0,0 +1,359 @@
+//===- CFGTest.cpp - CFG tests --------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CFG.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Assembly/Parser.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Pass.h"
+#include "llvm/PassManager.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+// This fixture assists in running the isPotentiallyReachable utility four ways
+// and ensuring it produces the correct answer each time.
+class IsPotentiallyReachableTest : public testing::Test {
+protected:
+ void ParseAssembly(const char *Assembly) {
+ M.reset(new Module("Module", getGlobalContext()));
+
+ SMDiagnostic Error;
+ bool Parsed = ParseAssemblyString(Assembly, M.get(),
+ Error, M->getContext()) == M.get();
+
+ std::string errMsg;
+ raw_string_ostream os(errMsg);
+ Error.print("", os);
+
+ if (!Parsed) {
+ // A failure here means that the test itself is buggy.
+ report_fatal_error(os.str().c_str());
+ }
+
+ Function *F = M->getFunction("test");
+ if (F == NULL)
+ report_fatal_error("Test must have a function named @test");
+
+ A = B = NULL;
+ for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
+ if (I->hasName()) {
+ if (I->getName() == "A")
+ A = &*I;
+ else if (I->getName() == "B")
+ B = &*I;
+ }
+ }
+ if (A == NULL)
+ report_fatal_error("@test must have an instruction %A");
+ if (B == NULL)
+ report_fatal_error("@test must have an instruction %B");
+ }
+
+ void ExpectPath(bool ExpectedResult) {
+ static char ID;
+ class IsPotentiallyReachableTestPass : public FunctionPass {
+ public:
+ IsPotentiallyReachableTestPass(bool ExpectedResult,
+ Instruction *A, Instruction *B)
+ : FunctionPass(ID), ExpectedResult(ExpectedResult), A(A), B(B) {}
+
+ static int initialize() {
+ PassInfo *PI = new PassInfo("isPotentiallyReachable testing pass",
+ "", &ID, 0, true, true);
+ PassRegistry::getPassRegistry()->registerPass(*PI, false);
+ initializeLoopInfoPass(*PassRegistry::getPassRegistry());
+ initializeDominatorTreePass(*PassRegistry::getPassRegistry());
+ return 0;
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<LoopInfo>();
+ AU.addRequired<DominatorTree>();
+ }
+
+ bool runOnFunction(Function &F) {
+ if (!F.hasName() || F.getName() != "test")
+ return false;
+
+ LoopInfo *LI = &getAnalysis<LoopInfo>();
+ DominatorTree *DT = &getAnalysis<DominatorTree>();
+ EXPECT_EQ(isPotentiallyReachable(A, B, 0, 0), ExpectedResult);
+ EXPECT_EQ(isPotentiallyReachable(A, B, DT, 0), ExpectedResult);
+ EXPECT_EQ(isPotentiallyReachable(A, B, 0, LI), ExpectedResult);
+ EXPECT_EQ(isPotentiallyReachable(A, B, DT, LI), ExpectedResult);
+ return false;
+ }
+ bool ExpectedResult;
+ Instruction *A, *B;
+ };
+
+ static int initialize = IsPotentiallyReachableTestPass::initialize();
+ (void)initialize;
+
+ IsPotentiallyReachableTestPass *P =
+ new IsPotentiallyReachableTestPass(ExpectedResult, A, B);
+ PassManager PM;
+ PM.add(P);
+ PM.run(*M);
+ }
+private:
+ OwningPtr<Module> M;
+ Instruction *A, *B;
+};
+
+}
+
+TEST_F(IsPotentiallyReachableTest, SameBlockNoPath) {
+ ParseAssembly(
+ "define void @test() {\n"
+ "entry:\n"
+ " bitcast i8 undef to i8\n"
+ " %B = bitcast i8 undef to i8\n"
+ " bitcast i8 undef to i8\n"
+ " bitcast i8 undef to i8\n"
+ " %A = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}\n");
+ ExpectPath(false);
+}
+
+TEST_F(IsPotentiallyReachableTest, SameBlockPath) {
+ ParseAssembly(
+ "define void @test() {\n"
+ "entry:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " bitcast i8 undef to i8\n"
+ " bitcast i8 undef to i8\n"
+ " %B = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}\n");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, StraightNoPath) {
+ ParseAssembly(
+ "define void @test() {\n"
+ "entry:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " br label %exit\n"
+ "exit:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}");
+ ExpectPath(false);
+}
+
+TEST_F(IsPotentiallyReachableTest, StraightPath) {
+ ParseAssembly(
+ "define void @test() {\n"
+ "entry:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " br label %exit\n"
+ "exit:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, DestUnreachable) {
+ ParseAssembly(
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %midblock\n"
+ "midblock:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "unreachable:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " br label %midblock\n"
+ "}");
+ ExpectPath(false);
+}
+
+TEST_F(IsPotentiallyReachableTest, BranchToReturn) {
+ ParseAssembly(
+ "define void @test(i1 %x) {\n"
+ "entry:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " br i1 %x, label %block1, label %block2\n"
+ "block1:\n"
+ " ret void\n"
+ "block2:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, SimpleLoop1) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %loop\n"
+ "loop:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " %A = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %loop, label %exit\n"
+ "exit:\n"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, SimpleLoop2) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " br label %loop\n"
+ "loop:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %loop, label %exit\n"
+ "exit:\n"
+ " ret void\n"
+ "}");
+ ExpectPath(false);
+}
+
+TEST_F(IsPotentiallyReachableTest, SimpleLoop3) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %loop\n"
+ "loop:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %loop, label %exit\n"
+ "exit:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " ret void\n"
+ "}");
+ ExpectPath(false);
+}
+
+
+TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther1) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %loop1\n"
+ "loop1:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %loop1, label %loop1exit\n"
+ "loop1exit:\n"
+ " br label %loop2\n"
+ "loop2:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " %y = call i1 @switch()\n"
+ " br i1 %x, label %loop2, label %loop2exit\n"
+ "loop2exit:"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther2) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %loop1\n"
+ "loop1:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %loop1, label %loop1exit\n"
+ "loop1exit:\n"
+ " br label %loop2\n"
+ "loop2:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " %y = call i1 @switch()\n"
+ " br i1 %x, label %loop2, label %loop2exit\n"
+ "loop2exit:"
+ " ret void\n"
+ "}");
+ ExpectPath(false);
+}
+
+TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOtherInsideAThirdLoop) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %outerloop3\n"
+ "outerloop3:\n"
+ " br label %innerloop1\n"
+ "innerloop1:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %innerloop1, label %innerloop1exit\n"
+ "innerloop1exit:\n"
+ " br label %innerloop2\n"
+ "innerloop2:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " %y = call i1 @switch()\n"
+ " br i1 %x, label %innerloop2, label %innerloop2exit\n"
+ "innerloop2exit:"
+ " ;; In outer loop3 now.\n"
+ " %z = call i1 @switch()\n"
+ " br i1 %z, label %outerloop3, label %exit\n"
+ "exit:\n"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
+
+TEST_F(IsPotentiallyReachableTest, BranchInsideLoop) {
+ ParseAssembly(
+ "declare i1 @switch()\n"
+ "\n"
+ "define void @test() {\n"
+ "entry:\n"
+ " br label %loop\n"
+ "loop:\n"
+ " %x = call i1 @switch()\n"
+ " br i1 %x, label %nextloopblock, label %exit\n"
+ "nextloopblock:\n"
+ " %y = call i1 @switch()\n"
+ " br i1 %y, label %left, label %right\n"
+ "left:\n"
+ " %A = bitcast i8 undef to i8\n"
+ " br label %loop\n"
+ "right:\n"
+ " %B = bitcast i8 undef to i8\n"
+ " br label %loop\n"
+ "exit:\n"
+ " ret void\n"
+ "}");
+ ExpectPath(true);
+}
Modified: llvm/trunk/unittests/Analysis/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Analysis/CMakeLists.txt?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/unittests/Analysis/CMakeLists.txt (original)
+++ llvm/trunk/unittests/Analysis/CMakeLists.txt Fri Jul 26 20:24:00 2013
@@ -1,5 +1,6 @@
set(LLVM_LINK_COMPONENTS
Analysis
+ AsmParser
)
add_llvm_unittest(AnalysisTests
Modified: llvm/trunk/unittests/Analysis/Makefile
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Analysis/Makefile?rev=187283&r1=187282&r2=187283&view=diff
==============================================================================
--- llvm/trunk/unittests/Analysis/Makefile (original)
+++ llvm/trunk/unittests/Analysis/Makefile Fri Jul 26 20:24:00 2013
@@ -9,7 +9,7 @@
LEVEL = ../..
TESTNAME = Analysis
-LINK_COMPONENTS := analysis
+LINK_COMPONENTS := analysis asmparser
include $(LEVEL)/Makefile.config
include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest
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