[llvm] r340250 - [NFC] Factor out predecessors collection into a separate method
Max Kazantsev via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 21 00:15:06 PDT 2018
Author: mkazantsev
Date: Tue Aug 21 00:15:06 2018
New Revision: 340250
URL: http://llvm.org/viewvc/llvm-project?rev=340250&view=rev
Log:
[NFC] Factor out predecessors collection into a separate method
It may be reused in a different piece of logic.
Differential Revision: https://reviews.llvm.org/D50890
Reviewed By: reames
Modified:
llvm/trunk/include/llvm/Analysis/MustExecute.h
llvm/trunk/lib/Analysis/MustExecute.cpp
Modified: llvm/trunk/include/llvm/Analysis/MustExecute.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/MustExecute.h?rev=340250&r1=340249&r2=340250&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/MustExecute.h (original)
+++ llvm/trunk/include/llvm/Analysis/MustExecute.h Tue Aug 21 00:15:06 2018
@@ -49,6 +49,13 @@ class LoopSafetyInfo {
// may throw.
bool HeaderMayThrow = false; // Same as previous, but specific to loop header
+ /// Collect all blocks from \p CurLoop which lie on all possible paths from
+ /// the header of \p CurLoop (inclusive) to BB (exclusive) into the set
+ /// \p Predecessors. If \p BB is the header, \p Predecessors will be empty.
+ void collectTransitivePredecessors(
+ const Loop *CurLoop, const BasicBlock *BB,
+ SmallPtrSetImpl<const BasicBlock *> &Predecessors) const;
+
public:
// Used to update funclet bundle operands.
DenseMap<BasicBlock *, ColorVector> BlockColors;
Modified: llvm/trunk/lib/Analysis/MustExecute.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MustExecute.cpp?rev=340250&r1=340249&r2=340250&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MustExecute.cpp (original)
+++ llvm/trunk/lib/Analysis/MustExecute.cpp Tue Aug 21 00:15:06 2018
@@ -98,19 +98,13 @@ static bool CanProveNotTakenFirstIterati
return SimpleCst->isAllOnesValue();
}
-
-bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop,
- const BasicBlock *BB,
- const DominatorTree *DT) const {
+void LoopSafetyInfo::collectTransitivePredecessors(
+ const Loop *CurLoop, const BasicBlock *BB,
+ SmallPtrSetImpl<const BasicBlock *> &Predecessors) const {
+ assert(Predecessors.empty() && "Garbage in predecessors set?");
assert(CurLoop->contains(BB) && "Should only be called for loop blocks!");
-
- // Fast path: header is always reached once the loop is entered.
if (BB == CurLoop->getHeader())
- return true;
-
- // Collect all transitive predecessors of BB in the same loop. This set will
- // be a subset of the blocks within the loop.
- SmallPtrSet<const BasicBlock *, 4> Predecessors;
+ return;
SmallVector<const BasicBlock *, 4> WorkList;
for (auto *Pred : predecessors(BB)) {
Predecessors.insert(Pred);
@@ -132,6 +126,21 @@ bool LoopSafetyInfo::allLoopPathsLeadToB
if (Predecessors.insert(PredPred).second)
WorkList.push_back(PredPred);
}
+}
+
+bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop,
+ const BasicBlock *BB,
+ const DominatorTree *DT) const {
+ assert(CurLoop->contains(BB) && "Should only be called for loop blocks!");
+
+ // Fast path: header is always reached once the loop is entered.
+ if (BB == CurLoop->getHeader())
+ return true;
+
+ // Collect all transitive predecessors of BB in the same loop. This set will
+ // be a subset of the blocks within the loop.
+ SmallPtrSet<const BasicBlock *, 4> Predecessors;
+ collectTransitivePredecessors(CurLoop, BB, Predecessors);
// Make sure that all successors of all predecessors of BB are either:
// 1) BB,
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