From e802a023d98b06307831cd122e61da86431e8dac Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 8 Oct 2002 21:06:27 +0000 Subject: [PATCH] Expose isCriticalEdge & SplitCriticalEdge methods from crit-edges pass git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4075 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Transforms/Scalar.h | 16 ++++++++++++++++ lib/Transforms/Scalar/BreakCriticalEdges.cpp | 19 ++++++++++--------- lib/Transforms/Utils/BreakCriticalEdges.cpp | 19 ++++++++++--------- 3 files changed, 36 insertions(+), 18 deletions(-) diff --git a/include/llvm/Transforms/Scalar.h b/include/llvm/Transforms/Scalar.h index 3161d68b0a0..1ade0f4977f 100644 --- a/include/llvm/Transforms/Scalar.h +++ b/include/llvm/Transforms/Scalar.h @@ -11,6 +11,7 @@ class Pass; class GetElementPtrInst; class PassInfo; +class TerminatorInst; //===----------------------------------------------------------------------===// // @@ -188,6 +189,21 @@ Pass *createCFGSimplificationPass(); Pass *createBreakCriticalEdgesPass(); extern const PassInfo *BreakCriticalEdgesID; +// The BreakCriticalEdges pass also exposes some low-level functionality that +// may be used by other passes. + +/// 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); + +/// SplitCriticalEdge - Insert a new node node to split the critical edge. This +/// will update DominatorSet, ImmediateDominator and DominatorTree information +/// if a pass is specified, thus calling this pass will not invalidate these +/// analyses. +/// +void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0); //===----------------------------------------------------------------------===// // diff --git a/lib/Transforms/Scalar/BreakCriticalEdges.cpp b/lib/Transforms/Scalar/BreakCriticalEdges.cpp index fa33fc7397d..b73ed55b8c9 100644 --- a/lib/Transforms/Scalar/BreakCriticalEdges.cpp +++ b/lib/Transforms/Scalar/BreakCriticalEdges.cpp @@ -28,8 +28,6 @@ namespace { AU.addPreserved(); AU.addPreservedID(LoopPreheadersID); // No preheaders deleted. } - private: - void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum); }; RegisterOpt X("break-crit-edges", @@ -45,9 +43,9 @@ Pass *createBreakCriticalEdgesPass() { return new BreakCriticalEdges(); } // Critical edges are edges from a block with multiple successors to a block // with multiple predecessors. // -static bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { +bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!"); - assert (TI->getNumSuccessors() > 1); + if (TI->getNumSuccessors() == 1) return false; const BasicBlock *Dest = TI->getSuccessor(SuccNum); pred_const_iterator I = pred_begin(Dest), E = pred_end(Dest); @@ -62,7 +60,7 @@ static bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { // will update DominatorSet, ImmediateDominator and DominatorTree information if // it is available, thus calling this pass will not invalidate either of them. // -void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ +void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P) { assert(isCriticalEdge(TI, SuccNum) && "Cannot break a critical edge, if it isn't a critical edge"); BasicBlock *TIBB = TI->getParent(); @@ -90,12 +88,15 @@ void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ PN->replaceUsesOfWith(TIBB, NewBB); } + // If we don't have a pass object, we can't update anything... + if (P == 0) return; + // Now update analysis information. These are the analyses that we are // currently capable of updating... // // Should we update DominatorSet information? - if (DominatorSet *DS = getAnalysisToUpdate()) { + if (DominatorSet *DS = P->getAnalysisToUpdate()) { // The blocks that dominate the new one are the blocks that dominate TIBB // plus the new block itself. DominatorSet::DomSetType DomSet = DS->getDominators(TIBB); @@ -104,14 +105,14 @@ void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ } // Should we update ImmdediateDominator information? - if (ImmediateDominators *ID = getAnalysisToUpdate()) { + if (ImmediateDominators *ID = P->getAnalysisToUpdate()) { // TIBB is the new immediate dominator for NewBB. NewBB doesn't dominate // anything. ID->addNewBlock(NewBB, TIBB); } // Should we update DominatorTree information? - if (DominatorTree *DT = getAnalysisToUpdate()) { + if (DominatorTree *DT = P->getAnalysisToUpdate()) { DominatorTree::Node *TINode = DT->getNode(TIBB); // The new block is not the immediate dominator for any other nodes, but @@ -131,7 +132,7 @@ bool BreakCriticalEdges::runOnFunction(Function &F) { if (TI->getNumSuccessors() > 1) for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) if (isCriticalEdge(TI, i)) { - SplitCriticalEdge(TI, i); + SplitCriticalEdge(TI, i, this); ++NumBroken; Changed = true; } diff --git a/lib/Transforms/Utils/BreakCriticalEdges.cpp b/lib/Transforms/Utils/BreakCriticalEdges.cpp index fa33fc7397d..b73ed55b8c9 100644 --- a/lib/Transforms/Utils/BreakCriticalEdges.cpp +++ b/lib/Transforms/Utils/BreakCriticalEdges.cpp @@ -28,8 +28,6 @@ namespace { AU.addPreserved(); AU.addPreservedID(LoopPreheadersID); // No preheaders deleted. } - private: - void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum); }; RegisterOpt X("break-crit-edges", @@ -45,9 +43,9 @@ Pass *createBreakCriticalEdgesPass() { return new BreakCriticalEdges(); } // Critical edges are edges from a block with multiple successors to a block // with multiple predecessors. // -static bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { +bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!"); - assert (TI->getNumSuccessors() > 1); + if (TI->getNumSuccessors() == 1) return false; const BasicBlock *Dest = TI->getSuccessor(SuccNum); pred_const_iterator I = pred_begin(Dest), E = pred_end(Dest); @@ -62,7 +60,7 @@ static bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) { // will update DominatorSet, ImmediateDominator and DominatorTree information if // it is available, thus calling this pass will not invalidate either of them. // -void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ +void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P) { assert(isCriticalEdge(TI, SuccNum) && "Cannot break a critical edge, if it isn't a critical edge"); BasicBlock *TIBB = TI->getParent(); @@ -90,12 +88,15 @@ void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ PN->replaceUsesOfWith(TIBB, NewBB); } + // If we don't have a pass object, we can't update anything... + if (P == 0) return; + // Now update analysis information. These are the analyses that we are // currently capable of updating... // // Should we update DominatorSet information? - if (DominatorSet *DS = getAnalysisToUpdate()) { + if (DominatorSet *DS = P->getAnalysisToUpdate()) { // The blocks that dominate the new one are the blocks that dominate TIBB // plus the new block itself. DominatorSet::DomSetType DomSet = DS->getDominators(TIBB); @@ -104,14 +105,14 @@ void BreakCriticalEdges::SplitCriticalEdge(TerminatorInst *TI,unsigned SuccNum){ } // Should we update ImmdediateDominator information? - if (ImmediateDominators *ID = getAnalysisToUpdate()) { + if (ImmediateDominators *ID = P->getAnalysisToUpdate()) { // TIBB is the new immediate dominator for NewBB. NewBB doesn't dominate // anything. ID->addNewBlock(NewBB, TIBB); } // Should we update DominatorTree information? - if (DominatorTree *DT = getAnalysisToUpdate()) { + if (DominatorTree *DT = P->getAnalysisToUpdate()) { DominatorTree::Node *TINode = DT->getNode(TIBB); // The new block is not the immediate dominator for any other nodes, but @@ -131,7 +132,7 @@ bool BreakCriticalEdges::runOnFunction(Function &F) { if (TI->getNumSuccessors() > 1) for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) if (isCriticalEdge(TI, i)) { - SplitCriticalEdge(TI, i); + SplitCriticalEdge(TI, i, this); ++NumBroken; Changed = true; }