namespace llvm {
+class BasicBlock;
class DependenceInfo;
class DominatorTree;
class Instruction;
const DominatorTree &DT,
const PostDominatorTree &PDT);
+/// Return true if \p BB0 and \p BB1 are control flow equivalent.
+/// Two basic blocks are control flow equivalent if when one executes, the other
+/// is guaranteed to execute. This is determined using dominators and
+/// post-dominators: if A dominates B and B post-dominates A then A and B are
+/// control-flow equivalent.
+bool isControlFlowEquivalent(const BasicBlock &BB0, const BasicBlock &BB1,
+ const DominatorTree &DT,
+ const PostDominatorTree &PDT);
+
/// Return true if \p I can be safely moved before \p InsertPoint.
bool isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
const DominatorTree &DT, const PostDominatorTree &PDT,
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/CodeMoverUtils.h"
using namespace llvm;
const FusionCandidate &FC1) const {
assert(FC0.Preheader && FC1.Preheader && "Expecting valid preheaders");
- BasicBlock *FC0EntryBlock = FC0.getEntryBlock();
- BasicBlock *FC1EntryBlock = FC1.getEntryBlock();
-
- if (DT.dominates(FC0EntryBlock, FC1EntryBlock))
- return PDT.dominates(FC1EntryBlock, FC0EntryBlock);
-
- if (DT.dominates(FC1EntryBlock, FC0EntryBlock))
- return PDT.dominates(FC0EntryBlock, FC1EntryBlock);
-
- return false;
+ return ::isControlFlowEquivalent(*FC0.getEntryBlock(), *FC1.getEntryBlock(),
+ DT, PDT);
}
/// Iterate over all loops in the given loop set and identify the loops that
bool llvm::isControlFlowEquivalent(const Instruction &I0, const Instruction &I1,
const DominatorTree &DT,
const PostDominatorTree &PDT) {
- const BasicBlock *BB0 = I0.getParent();
- const BasicBlock *BB1 = I1.getParent();
- return ((DT.dominates(BB0, BB1) && PDT.dominates(BB1, BB0)) ||
- (PDT.dominates(BB0, BB1) && DT.dominates(BB1, BB0)));
+ return isControlFlowEquivalent(*I0.getParent(), *I1.getParent(), DT, PDT);
+}
+
+bool llvm::isControlFlowEquivalent(const BasicBlock &BB0, const BasicBlock &BB1,
+ const DominatorTree &DT,
+ const PostDominatorTree &PDT) {
+ if (&BB0 == &BB1)
+ return true;
+
+ return ((DT.dominates(&BB0, &BB1) && PDT.dominates(&BB1, &BB0)) ||
+ (PDT.dominates(&BB0, &BB1) && DT.dominates(&BB1, &BB0)));
}
static bool reportInvalidCandidate(const Instruction &I,