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| author | Rafael Espindola <rafael.espindola@gmail.com> | 2012-03-30 16:46:21 +0000 |
|---|---|---|
| committer | Rafael Espindola <rafael.espindola@gmail.com> | 2012-03-30 16:46:21 +0000 |
| commit | 092c5ccf5bdcaa53151645e5628cec77fcf4062b (patch) | |
| tree | 8d189635dc35b19fea16c151d3b4b61bb1ec2764 /include | |
| parent | 0e4fa5ff365fccff46870b7d5d8d4d1d46e77986 (diff) | |
| download | external_llvm-092c5ccf5bdcaa53151645e5628cec77fcf4062b.zip external_llvm-092c5ccf5bdcaa53151645e5628cec77fcf4062b.tar.gz external_llvm-092c5ccf5bdcaa53151645e5628cec77fcf4062b.tar.bz2 | |
Handle unreachable code in the dominates functions. This changes users when
needed for correctness, but still doesn't clean up code that now unnecessary
checks for reachability.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153755 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include')
| -rw-r--r-- | include/llvm/Analysis/Dominators.h | 31 | ||||
| -rw-r--r-- | include/llvm/Analysis/LoopInfo.h | 3 |
2 files changed, 28 insertions, 6 deletions
diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h index 0d2222d..f2ccb6e 100644 --- a/include/llvm/Analysis/Dominators.h +++ b/include/llvm/Analysis/Dominators.h @@ -359,8 +359,19 @@ public: bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A, const DomTreeNodeBase<NodeT> *B) const { + // A node trivially dominates itself. + if (B == A) + return true; + + // An unreachable node is dominated by anything. + if (!isReachableFromEntry(B)) + return true; + + // And dominates nothing. + if (!isReachableFromEntry(A)) + return false; + const DomTreeNodeBase<NodeT> *IDom; - if (A == 0 || B == 0) return false; while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B) B = IDom; // Walk up the tree return IDom != 0; @@ -369,10 +380,14 @@ public: /// isReachableFromEntry - Return true if A is dominated by the entry /// block of the function containing it. - bool isReachableFromEntry(const NodeT* A) { + bool isReachableFromEntry(const NodeT* A) const { assert(!this->isPostDominator() && "This is not implemented for post dominators"); - return dominates(&A->getParent()->front(), A); + return isReachableFromEntry(getNode(const_cast<NodeT *>(A))); + } + + inline bool isReachableFromEntry(const DomTreeNodeBase<NodeT> *A) const { + return A; } /// dominates - Returns true iff A dominates B. Note that this is not a @@ -380,10 +395,16 @@ public: /// inline bool dominates(const DomTreeNodeBase<NodeT> *A, const DomTreeNodeBase<NodeT> *B) { + // A node trivially dominates itself. if (B == A) - return true; // A node trivially dominates itself. + return true; - if (A == 0 || B == 0) + // An unreachable node is dominated by anything. + if (!isReachableFromEntry(B)) + return true; + + // And dominates nothing. + if (!isReachableFromEntry(A)) return false; // Compare the result of the tree walk and the dfs numbers, if expensive diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h index 8f44bed94..4921629 100644 --- a/include/llvm/Analysis/LoopInfo.h +++ b/include/llvm/Analysis/LoopInfo.h @@ -762,7 +762,8 @@ public: InvBlockTraits::child_begin(BB), E = InvBlockTraits::child_end(BB); I != E; ++I) { typename InvBlockTraits::NodeType *N = *I; - if (DT.dominates(BB, N)) // If BB dominates its predecessor... + // If BB dominates its predecessor... + if (DT.dominates(BB, N) && DT.isReachableFromEntry(N)) TodoStack.push_back(N); } |